Compositions and methods for treating lupus nephritis

Abstract

The present disclosure relates generally to methods of treating lupus nephritis in a subject in need thereof. The method includes determining that the subject has at least one of the following characteristics: an elevated C4x level; an increased C4x / C4 ratio, a reduced C4 level; an elevated level of the C1sC1 inhibitor; an elevated C1sC1 inhibitor / C1s ratio; a reduced C1s level; an elevated C2b level; an increased C2b / C2 ratio; a reduced C2 level; or an elevated level of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); wherein C4x is selected from the group consisting of C4a, C4b, and C4d, and administering to the subject an inhibitor of the classical complement pathway.

Description

[0001] Related Applications

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 341,835, filed on May 13, 2022, which is hereby incorporated by reference in its entirety. Background Art

[0003] Systemic lupus erythematosus (SLE) is a biologically and clinically heterogeneous autoimmune disease characterized by a wide variety of clinical involvement, particularly of the kidneys. SLE is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary from person to person and can range from mild to severe. Common symptoms include joint pain and swelling, fever, chest pain, hair loss, mouth ulcers, swollen lymph nodes, feeling tired, and a rash that most commonly occurs on the face. There are usually periods of illness called "febrile periods," as well as periods of remission, during which there are few symptoms.

[0004] The cause of SLE is still unclear. It is thought to involve genetics and environmental factors. There are many other types of lupus erythematosus, including discoid lupus erythematosus, neonatal lupus and subacute cutaneous lupus erythematosus. The kidney involvement of SLE is called lupus nephritis (LN). Up to 50% to 60% of SLE patients develop LN within the first 10 years of illness, and it is the main cause of morbidity and mortality in these patients. To date, lupus nephritis remains incurable. The only option is to help control symptoms, prevent flare-ups and reduce organ damage. Therefore, there is a need in the art for new therapies to prevent and treat lupus nephritis. Summary of the invention

[0005] The present disclosure is generally directed to methods of treating lupus nephritis in a subject in need thereof. The methods include determining that the subject has at least one of the following characteristics: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. C4x can be selected from the group consisting of C4a and C4d. The method also includes administering to the subject an inhibitor of the classical complement pathway, e.g., if the subject has elevated C4x levels, elevated C4x / C4 ratio, decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated PACA1 and / or PACA3 levels. A therapeutically effective amount of the inhibitor can be administered.

[0006] In some embodiments, the subject has at least two of the characteristics. For example, the characteristics can be selected from elevated C4x levels, elevated C4x / C4 ratios, and decreased C4 levels, and / or the characteristics can be selected from the group consisting of elevated C1sC1 inhibitor levels, elevated C1sC1 inhibitor / C1s ratios, and decreased C1s levels. In some embodiments, the subject also has elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. In some embodiments, the subject has at least one of the following additional characteristics: elevated C3a levels; elevated C3a / C3 ratios; or decreased C3 levels.

[0007] In some embodiments, the subject has an elevated C4x level. In some embodiments, the subject also has at least one of the following additional features: elevated C4x / C4 ratio; decreased C4 level; elevated C1sC1 inhibitor level; elevated C1sC1 inhibitor / C1s ratio; decreased C1s level; elevated C2b level; elevated C2b / C2 ratio; decreased C2 level; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a level; elevated C3a / C3 ratio; or decreased C3 level.

[0008] In some embodiments, the elevated C4x level is greater than the C4x level of a normal or healthy subject, greater than the C4x level of a normal or healthy subject of similar age, or greater than a reference C4x level. The reference C4x level may be a value equal to or greater than the mean or median of the C4x levels in samples from subjects with lupus nephritis, or a value equal to or greater than the mean or median of the C4x levels in samples from subjects with lupus nephritis of similar age. The reference C4x level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples from age-matched lupus nephritis subjects. The reference C4x level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples from normal or healthy subjects. The reference C4x level can be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C4x levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C4x level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% greater than the reference C4x level. or 500%, or the elevated C4x level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C4x level.

[0009] In some embodiments, the subject has an elevated C4x / C4 ratio. In some embodiments, the subject also has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C4x / C4 ratio is greater than the C4x / C4 ratio of a normal or healthy subject, greater than the C4x / C4 ratio of a normal or healthy subject of comparable age, or greater than a reference C4x / C4 ratio. The reference C4x / C4 ratio may be a value equal to or greater than the mean or median of C4x / C4 ratios in samples from subjects with lupus nephritis, or may be equal to or greater than the mean or median of C4x / C4 ratios in samples from subjects with lupus nephritis of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C4x / C4 ratios in samples from subjects with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in samples from age-matched lupus nephritis subjects. The reference C4x / C4 ratio may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in samples from normal or healthy subjects. The reference C4x / C4 ratio can be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the elevated C4x / C4 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, 4500%, 5000%, 6500%, 7000%, 75000%, 80000%, 85000%, 90000%, 850000%, 900000%, 8500000%, 8500000% or 9 ... %, 400% or 500% higher than the reference C4x / C4 ratio, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference C4x / C4 ratio.

[0010] In some embodiments, the subject has decreased C4 levels. In some embodiments, the subject also has at least one of the following additional features: increased C4x levels; increased C4x / C4 ratio; increased C1sC1 inhibitor levels; increased C1sC1 inhibitor / C1s ratio; decreased C1s levels; increased C2b levels; increased C2b / C2 ratio;

[0011] Decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the reduced C4 level is less than the C4 level of a normal or healthy subject. The reduced C4 level may be less than the C4 level of a normal or healthy subject of similar age, may be less than a reference C4 level, or may be a value equal to or less than the mean or median of C4 levels in samples derived from lupus nephritis subjects. In some embodiments, the reference C4 level is a value equal to or less than the mean or median of C4 levels in samples derived from lupus nephritis subjects of similar age. The reference C4 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in samples from subjects with lupus nephritis. The reference C4 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in samples from subjects with lupus nephritis of similar age. The reference C4 level may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C4 levels in samples from normal or healthy subjects. The reference C4 level may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C4 levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis.In some embodiments, the decreased C4 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3 ... %-200%, 200%-300%, 300%-400%, 400%-500% below the reference C4 level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% below the reference C4 level.

[0012] In some embodiments, the subject has an elevated C1sC1 inhibitor level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C1sC1 inhibitor level is greater than the C1sC1 inhibitor level of a normal or healthy subject, greater than the C1sC1 inhibitor level of a normal or healthy subject of similar age, or greater than a reference C1sC1 inhibitor level. The reference C1sC1 inhibitor level may be a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples from subjects with lupus nephritis, or may be a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples from subjects with lupus nephritis of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C1sC1 inhibitor levels in samples from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples from age-matched lupus nephritis subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level can be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the elevated C1sC1 inhibitor level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3 ... 0%, 400% or 500% above the reference C1sC1 inhibitor level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% above the reference C1sC1 inhibitor level.

[0013] In some embodiments, the subject has an elevated C1sC1 inhibitor / C1s ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C4x / C4 ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject of comparable age. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than a reference C1sC1 inhibitor / C1s ratio. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject.In some embodiments, the reference C1sC1 inhibitor / C1s ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in a sample from an age-matched normal or healthy subject. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C1sC1 inhibitor / C1s ratio. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C1sC1 inhibitor / C1s ratio.

[0014] In some embodiments, the subject has a decreased C1s level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the decreased C1s level is less than the C1s level of a normal or healthy subject. In some embodiments, the decreased C1s level is less than the C1s level of a normal or healthy subject of similar age. In some embodiments, the decreased C1s level is less than a reference C1s level. In some embodiments, the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from normal or healthy subjects.In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the reduced C1s level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% lower than the reference C4 level. In some embodiments, the reduced C1s level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

[0015] In some embodiments, the subject has an elevated C2b level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C2b level is greater than the C2b level of a normal or healthy subject, the elevated C2b level is greater than the C2b level of a normal or healthy subject of similar age, or is greater than a reference C2b level. The reference C2b level may be a value equal to or greater than the mean or median of C2b levels in samples from subjects with lupus nephritis, or a value equal to or greater than the mean or median of C2b levels in samples from subjects with lupus nephritis of similar age. The reference C2b level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples from age-matched lupus nephritis subjects. The reference C2b level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples from normal or healthy subjects. The reference C2b level can be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C2b levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the elevated C2b level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300% greater than the reference C2b level. , 400% or 500% higher than the reference C2b level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference C2b level.

[0016] In some embodiments, the subject has an elevated C2b / C2 ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; decreased C2 levels; elevated C2b levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject. In some embodiments, the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject of similar age. In some embodiments, the elevated C2b / C2 ratio is greater than a reference C2b / C2 ratio. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the mean or median of the C2b / C2 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the mean or median of the C2b / C2 ratio in samples derived from lupus nephritis subjects of similar age. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C2b / C2 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples from normal or healthy subjects.In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in a sample from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C2b / C2 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C2b / C2 ratio. In some embodiments, the elevated C2b / C2 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C2b / C2 ratio.

[0017] In some embodiments, the subject has a decreased C2 level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the decreased C2 level is less than the C2 level of a normal or healthy subject, less than the C2 level of a normal or healthy subject of similar age, or less than a reference C2 level. The reference C2 level may be a value equal to or less than the mean or median of C2 levels in samples derived from subjects with lupus nephritis, or may be a value equal to or less than the mean or median of C2 levels in samples derived from subjects with lupus nephritis of similar age. The reference C2 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile of C2 levels in samples derived from subjects with lupus nephritis. The reference C2 level can be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C2 levels in samples from age-matched lupus nephritis subjects. The reference C2 level may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from normal or healthy subjects, or may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis.In some embodiments, the decreased C2 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 75000%, 80000%, 85000%, 90000%, 850000%, 90 ... %-200%, 200%-300%, 300%-400%, 400%-500% below the reference C2 level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% below the reference C2 level.

[0018] In some embodiments, the subject has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3). In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels.

[0019] In some embodiments, the elevated PACA1 and / or PACA3 levels are greater than the PACA1 and / or PACA3 levels of normal or healthy subjects, greater than the PACA1 and / or PACA3 levels of normal or healthy subjects of similar age, or greater than a reference PACA1 and / or PACA3 level. The reference PACA1 and / or PACA3 level can be a value equal to or greater than the mean or median of the PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis, or can be a value equal to or greater than the mean or median of the PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis of similar age. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis of similar age. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in a sample derived from a normal or healthy subject, or may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in a sample derived from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis.In some embodiments, the elevated PACA1 and / or PACA3 levels are at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200% higher than the reference PACA1 and / or PACA3 levels. , 300%, 400% or 500% higher than the reference PACA1 and / or PACA3 levels, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference PACA1 and / or PACA3 levels.

[0020] In some embodiments, the subject has an elevated C3a level. In some embodiments, the subject has at least one of the following additional features: elevated C4x / C4 ratio; decreased C4 level; elevated C1sC1 inhibitor level; elevated C1sC1 inhibitor / C1s ratio; decreased C1s level; elevated C2b level; elevated C2b / C2 ratio; decreased C2 level; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C4x level; elevated C3a / C3 ratio; or decreased C3 level. In some embodiments, the elevated C3a level is greater than the C3a level of a normal or healthy subject. In some embodiments, the elevated C3a level is greater than the C3a level of a normal or healthy subject of similar age. In some embodiments, the elevated C3a level is greater than a reference C3a level. In some embodiments, the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C3a level is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C3a levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C3a level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C3a level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples from normal or healthy subjects. In some embodiments, the reference C3a level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples derived from normal or healthy subjects of similar age.In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the elevated C3a level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C3a level. In some embodiments, the elevated C3a level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C3a level.

[0021] In some embodiments, the subject has an elevated C3a / C3 ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C4x / C4 ratio; or decreased C3 levels. In some embodiments, the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject. In some embodiments, the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject of similar age. In some embodiments, the elevated C3a / C3 ratio is greater than the reference C3a / C3 ratio. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the mean or median of the C3a / C3 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the mean or median of the C3a / C3 ratio in samples derived from lupus nephritis subjects of similar age. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C3a / C3 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C3a / C3 ratio is equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C3a / C3 ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in samples from normal or healthy subjects.In some embodiments, the reference C3a / C3 ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in a sample from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C3a / C3 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C3a / C3 ratio. In some embodiments, the elevated C3a / C3 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C3a / C3 ratio.

[0022] In some embodiments, the subject has a reduced C3 level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; reduced C1s levels; elevated C2b levels; elevated C2b / C2 ratio; reduced C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or reduced C4 levels. In some embodiments, the reduced C3 level is less than the C3 level of a normal or healthy subject. In some embodiments, the reduced C3 level is less than the C3 level of a normal or healthy subject of similar age. In some embodiments, the reduced C3 level is less than a reference C3 level. In some embodiments, the reference C3 level is equal to or less than the mean or median value of the C3 level in the sample derived from a subject with lupus nephritis. In some embodiments, the reference C3 level is equal to or less than the mean or median value of the C3 level in the sample derived from a subject with lupus nephritis of similar age. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile value of the C3 level in the sample derived from a subject with lupus nephritis. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples from normal or healthy subjects. In some embodiments, the reference C3 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples derived from normal or healthy subjects of similar age.In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the reduced C3 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% lower than the reference C4 level. In some embodiments, the reduced C3 level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

[0023] In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured in a biological sample. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured in plasma or urine. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 12 months prior to administration of a therapeutically effective amount of an inhibitor of the classical complement pathway. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 6 months prior to administration of an inhibitor. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 3 months prior to administration of an inhibitor.In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 1 month prior to administration of an inhibitor.

[0024] In some embodiments, the subject has an elevated urine protein / creatinine ratio (UPCR) level. In some embodiments, the elevated UPCR level is greater than the UPCR level of a normal or healthy subject, greater than the UPCR level of a normal or healthy subject of similar age, or greater than a reference UPCR level. The reference UPCR level may be equal to or greater than about 0.5 g / g, 1.0 g / g, 1.5 g / g, 2.0 g / g, 2.5 g / g, 3.0 g / g, 3.5 g / g, 4.0 g / g, 4.5 g / g, or 5.0. The elevated UPCR level may be at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, or 5000% higher than the UPCR level in a normal or healthy subject or the reference UPCR level. The elevated UPCR level may be at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, 400%-500%, 500%-600%, 600%-700%, 700%-800%, 800%-900%, 900%-1000%, 1000%-2000%, 2000%-3000%, 3000%-4000%, or 4000-5000% higher than the UPCR level in a normal or healthy subject or the reference UPCR level. In some embodiments, the UPCR levels are measured in urine.

[0025] In some embodiments, the classical complement inhibitor is a C1 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent. In some embodiments, the antibody is a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a humanized antibody, a chimeric antibody, a multispecific antibody or an antibody derivative thereof.

[0026] In some embodiments, the inhibitor of the classical complement pathway is a C1q inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent. In some embodiments, the antibody is a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a humanized antibody, a chimeric antibody, a multispecific antibody or an antibody derivative thereof. The antibody may be an anti-C1q antibody. In some embodiments, the antibody derivative thereof is a one-armed antibody.

[0027] In some embodiments, the antibody is administered at a dose of at least 50 mg / kg, or at a dose between 50 mg / kg and 200 mg / kg. The antibody can be administered in an amount of 50 mg / kg, 55 mg / kg, 60 mg / kg, 65 mg / kg, 70 mg / kg, 75 mg / kg, 80 mg / kg, 85 mg / kg, 90 mg / kg, 95 mg / kg, 100 mg / kg, 105 mg / kg, 110 mg / kg, 115 mg / kg, 120 mg / kg, 125 mg / kg, 130 mg / kg, 135 mg / kg, 140 mg / kg, 145 mg / kg, 150 mg / kg, 155 mg / kg, 160 mg / kg, 165 mg / kg, 170 mg / kg, 175 mg / kg, 180 mg / kg, 185 mg / kg, 190 mg / kg, 195 mg / kg or 200 mg / kg. In some embodiments, the antibody is administered in an amount of at least 50 mg. The antibody can be administered at a total dose of 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 105 mg, 110 mg, 115 mg, 120 mg, 125 mg, 130 mg, 135 mg, 140 mg, 145 mg, 150 mg, 155 mg, 160 mg, 165 mg, 170 mg, 175 mg, 180 mg, 185 mg, 190 mg, 195 mg or 200 mg. In some embodiments, the antibody is administered daily, weekly, every other week, monthly, every six weeks, or every other month. In some embodiments, the antibody is administered for at least 3 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months, preferably at least 6 months. The antibody can be administered throughout the patient's life, or intermittently throughout the patient's life, for example in response to fever. In some embodiments, the antibody is administered at a dose of 75 mg / kg on day 1 and on day 5 or day 6. In some embodiments, the antibody is further administered at a dose of 100 mg / kg every two weeks. In some embodiments, the antibody is administered intravenously.

[0028] In some embodiments, the antibody is an antibody fragment, such as a Fab fragment, a Fab' fragment, a F(ab')2 fragment, a Fv fragment, a diabody or a single-chain antibody molecule. In some embodiments, the antibody fragment is administered at a total dose of at least 250 mg or at a total dose between 250 mg and 1000 mg. In some embodiments, the antibody fragment is administered at a total dose of 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, 500 mg, 525 mg, 550 mg, 575 mg, 600 mg, 625 mg, 650 mg, 675 mg, 700 mg, 725 mg, 750 mg, 775 mg, 800 mg, 825 mg, 850mg, 875mg, 900mg, 925mg, 950mg, 975mg, 1000mg, 1250mg, 1275mg, 1300mg, 1325mg, 1350mg, 13 75mg, 1400mg, 1425mg, 1450mg, 1475mg, 1500mg, 1525mg, 1550mg, 1575mg, 1600mg, 1625mg, 1650mg , 1675mg, 1700mg, 1725mg, 1750mg, 1775mg, 1800mg, 1825mg, 1850mg, 1875mg, 1900mg, 1925mg, 19 50mg, 1975mg, 2000mg, 2250mg, 2275mg, 2300mg, 2325mg, 2350mg, 2375mg, 2400mg, 2425mg, 2450mg , 2475mg, 2500mg, 2525mg, 2550mg, 2575mg, 2600mg, 2625mg, 2650mg, 2675mg, 2700mg, 2725mg, 2750mg, 2775mg, 2800mg, 2825mg, 2850mg, 2875mg, 2900mg, 2925mg, 2950mg, 2975mg or 3000mg total dose is administered. In some embodiments, the antibody fragment is administered with a total dose of about 750mg. In some embodiments, the antibody fragment is administered daily, once every other day, once every three days, once every four days, once every five days or once every six days, once a week, once every two weeks or once a month. In some embodiments, the antibody fragment is administered three times a week. In some embodiments, the antibody fragment is administered for at least 3 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months. The antibody fragment can be administered throughout the patient's life, or intermittently throughout the patient's life, for example in response to fever.In some embodiments, the antibody fragment is administered subcutaneously.

[0029] In some embodiments, the anti-C1q antibody inhibits the interaction between C1q and autoantibodies, or between C1q and C1r, or between C1q and C1s, and / or promotes the clearance of C1q from the circulation or tissues. In some embodiments, the antibody comprises: a light chain variable domain comprising HVR-L1 having an amino acid sequence of SEQ ID NO:5, HVR-L2 having amino acids of SEQ ID NO:6, and HVR-L3 having amino acids of SEQ ID NO:7; and / or a heavy chain variable domain comprising HVR-H1 having an amino acid sequence of SEQ ID NO:9, HVR-H2 having amino acids of SEQ ID NO:10, and HVR-H3 having amino acids of SEQ ID NO:11. In some embodiments, the antibody comprises a light chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NOs:4 and 35-38, and wherein the light chain variable domain comprises HVR-L1 having an amino acid sequence of SEQ ID NO:5, HVR-L2 having amino acids of SEQ ID NO:6, and HVR-L3 having amino acids of SEQ ID NO:7, preferably the light chain variable domain comprises an amino acid sequence selected from SEQ ID NOs:4 and 35-38. In some embodiments, the antibody comprises a heavy chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NOs: 8 and 31-34, and wherein the heavy chain variable domain comprises HVR-H1 having an amino acid sequence of SEQ ID NO: 9, HVR-H2 having amino acids of SEQ ID NO: 10, and HVR-H3 having amino acids of SEQ ID NO: 11, preferably the heavy chain variable domain comprises an amino acid sequence selected from SEQ ID NOs: 8 and 31-34. In some embodiments, the antibody fragment comprises a heavy chain Fab fragment of SEQ ID NO: 39 and a light chain Fab fragment of SEQ ID NO: 40.

[0030] In some embodiments, the inhibitor of the classical complement pathway is a C1r inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent, preferably an anti-C1r antibody. In some embodiments, the anti-C1r antibody inhibits the interaction between C1r and C1q or between C1r and C1s, or wherein the anti-C1r antibody inhibits the catalytic activity of C1r, or it inhibits the processing of C1r into an active protease.

[0031] In some embodiments, the inhibitor of the classical complement pathway is a C1s inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent, preferably an anti-C1s antibody. In some embodiments, the anti-C1s antibody inhibits the interaction between C1s and C1q, or between C1s and C1r, or between C1s and C2 or C4, or wherein the anti-C1s antibody inhibits the catalytic activity of C1s, or it inhibits the processing of pro-C1s into an active protease, or it binds to an activated form of C1s. In some embodiments, the antibody is sutimlimab.

[0032] In some embodiments, the inhibitor of the classical complement pathway is an anti-C1 complex antibody, optionally wherein the anti-C1 complex antibody inhibits C1r or C1s activation or blocks their ability to act on C2 or C4. The anti-C1 complex antibody binds to a combinatorial epitope within the C1 complex, wherein the combinatorial epitope comprises amino acids of both C1q and C1s; amino acids of both C1q and C1r; amino acids of both C1r and C1s; or amino acids of each of C1q, C1r, and C1s.

[0033] In some embodiments, the inhibitor of the classical complement pathway is a C2 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent. The C2 inhibitor can be ARGX-117 (Argenx).

[0034] In some embodiments, the inhibitor of the classical complement pathway is a C3 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent. The C3 inhibitor can be APL-9 (Apellis) or AMY-101 (Amyndas).

[0035] In some embodiments, the inhibitor of the classical complement pathway is a C4 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It has been shown that systemic lupus erythematosus (SLE) is driven by autoantibodies against many self-antigens, including DNA.

[0037] Figure 2 Excessive immune complex (IC) and C1q glomerular deposition induces local complement-mediated inflammation, destroying glomerular basement membrane (GBM) structure and function. PACA is a pathogenic anti-C1q antibody.

[0038] Figure 3 Patient demographics are shown.

[0039] Figure 4showed that higher circulating C4d / C4 ratios in patients with active lupus nephritis (LN) suggest that complement may drive disease progression and severity.

[0040] Figure 5 showed that LN patients with a high C4d / C4 ratio exhibited coordinated classical complement activation.

[0041] Figure 6 showed that the high correlation between complement factors in LN patients indicated coordinated pathway activity.

[0042] Figure 7 It is shown that no correlation was observed in the healthy control group.

[0043] Figure 8A-B It was shown that active LN patients with high C4d / C4 ratios may have higher PACA1.

[0044] Fig. 9 showed that, following standard of care, C4d / C4 was reduced after a febrile event, but the effect was not sustained.

[0045] Fig.10 Shown are changes in urine protein / creatinine ratio (UPCR) and C4 in response to standard of care treatment.

[0046] Fig.11 showed that clinical C4 measurements tracked the UPCR trajectory.

[0047] Fig.12 It was shown that an increase in C4 and a decrease in C4d / C4 were associated with improved disease activity. The SLEDAI (Systemic Lupus Erythematosus Disease Activity Index) is an objective measure of overall disease activity consistent with a list of organ manifestations over the last 10 days.

[0048] Fig.13 It was shown that PACA of the IgG1 and IgG3 isotypes provided the strongest correlation with UPCR, whereas there was no significant correlation with the levels of IgG2 and IgG4 antibodies to C1q.

[0049] Fig.14 It was shown that PACA1 and PACA3 levels were correlated with C4d and the C4d / C4 ratio.

[0050] Fig.15 showed that the deposition of C4d in renal biopsies indicated the involvement of the classical complement pathway in LN.

[0051] Fig.16 The results showed that this biomarker identified SLE patients with LN with high accuracy.

[0052] Fig.17It was shown that early studies in animal models of lupus nephritis reported a causal relationship between anti-C1q antibodies and kidney damage.

[0053] Fig.18 The results showed that the administration of PACA significantly aggravated the disease and significantly increased the complement deposition in the subendothelial space of the glomeruli.

[0054] Fig.19 These results suggest that the binding of PACA to substrate-bound C1q is not affected by soluble C1q.

[0055] Fig. 20 showed that anti-C1q IgG1 and IgG3, but not IgG4 levels, correlated with serum C4d / C4.

[0056] Figure 21A-Figure 21P is a box plot showing complement factors in healthy controls (HC) and patients with active lupus nephritis. The boxes in the figure represent the 25th, 50th, and 75th percentiles of the subject levels.

[0057] Fig. 22 Is a correlation matrix showing anti-correlation or positive correlation between complement factors in patients with lupus nephritis, and indicates synergistic pathway activity. The circle size indicates the correlation distance between features (row x column). The circle shading indicates the Spearman correlation distance, which ranges from anti-correlation (e.g., "-1") to positive correlation (e.g., "+1" shown on the Y axis). The importance of the correlation is indicated by the asterisk in the circle. The asterisk indicates the p value of each correlation; that is, P value <0.001 (***), P value <0.01 (**); and P value <0.05 (*).

[0058] Figure 23A-23F is a graph showing the therapeutic effect of FabA on complement factors in patients with lupus nephritis. DETAILED DESCRIPTION

[0059] This detailed description should not be considered limiting, but is merely for illustrating the general principles of the invention. The section headings and overall structure of this detailed description are for convenience only and are not intended to limit the invention.

[0060] In lupus nephritis (LN), inhibition of C1q (assessed by free C1q in serum or plasma) with anti-C1q inhibitors (including but not limited to anti-C1q Fab fragments) reduces downstream complement activation (e.g., complement factors C4 and its activation products, C2 and its activation products, C3 and its activation products, C5 and its activation products, etc.) and complement-mediated renal inflammation.

[0061] Lupus nephritis may be an autoantibody-mediated disease with a unique involvement of the C1q / classical complement cascade. Systemic lupus erythematosus (SLE) is driven by autoantibodies against many self-antigens, including DNA ( Figure 1 ). Normal clearance of immune complexes (IC) is overwhelmed. Excessive IC and C1q glomerular deposition induces local complement-mediated inflammation, destroying the glomerular basement membrane (GBM) structure and function ( Figure 2 ). The data disclosed herein indicate that high plasma C4d / C4 identifies lupus nephritis patients with disease mediated by activation of the classical complement pathway. PACA (pathogenic anti-C1q antibodies) amplify complement activation, perpetuating tissue damage. Complement activation via the classical pathway can be measured by the C4d / C4 ratio with high specificity.

[0062] A unique precision medicine strategy for lupus nephritis

[0063] The data from Example 1 demonstrate that patients identified using a model that assesses elevated C4d levels and / or elevated C4d / C4 ratios exhibit clinical improvement with anti-C1q antibody treatment. The data from Example 1 also demonstrates a strong association between high C4d / C4 ratios and the presence of PACA, as well as strong associations between other complement factors in LN patients, e.g., C4d / C4 and C4d have a strong positive correlation, and C2b and C2b / C2 have a strong inverse correlation ( Fig. 22 ). This correlation is used to select patients most likely to respond to therapy with the classical complement pathway, more specifically anti-C1q therapy. Similarly, Fig. 22 Inverse or positive correlations between other complement factors (such as C4x levels; C4x / C4 ratio; C4 levels; C1sC1 inhibitor levels; C1sC1 inhibitor / C1s ratio; C1s levels; C2b levels; C2b / C2 ratio; C2 levels; pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels) in patients with lupus nephritis were shown, indicating synergistic pathway activity.

[0064] The present disclosure is generally directed to methods of treating lupus nephritis in a subject in need thereof. The methods include determining that the subject has at least one of the following characteristics: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. C4x can be selected from the group consisting of C4a and C4d. The method further includes administering to the subject an inhibitor of the classical complement pathway, e.g., if the subject has elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. A therapeutically effective amount of the inhibitor can be administered.

[0065] All sequences mentioned in the present disclosure are incorporated by reference from U.S. Patent No. 10,316,081, U.S. Patent Application No. 14 / 890,811, U.S. Patent No. 8,877,197, U.S. Patent No. 9,708,394, U.S. Patent Application No. 15 / 360,549, U.S. Patent No. 9,562,106, U.S. Patent No. 10,450,382, U.S. Patent No. 10,457,745, International Patent Application No. PCT / US2018 / 022462, each of which is hereby incorporated by reference for the disclosed antibodies and related compositions.

[0066] definition

[0067] As used herein in the specification, "a" or "an" may mean one or more. As used herein in one or more claims, when used in conjunction with the word "comprising", the word "a" or "an" may mean one or more than one. For example, a reference to an "antibody" is a reference to one to more than one antibodies. As used herein, "another" may mean at least a second or more than one.

[0068] As used herein, "reference level" refers to a predetermined standard used as a reference for evaluating the value or data obtained from a sample obtained from an individual. The reference level can be an absolute value; a relative value; a value with an upper or lower limit; a range of values; an average value; a median value; an average value; or a value compared to a specific control or baseline value. The reference level can be based on a single sample value, for example, a value obtained from a sample of a tested subject, but at an earlier time point. The reference level can be based on a large number of samples, such as from a subject population with a similar actual age, gender, disease state or other matching group, or based on a sample pool including or excluding the sample being tested. The reference level can also be determined based on a representative number of samples (e.g., plasma) from different individuals with lupus nephritis. The reference level can also be determined from biological samples of individuals who have never had lupus nephritis (i.e., normal or healthy subjects of similar age). These biological samples from individuals with lupus nephritis or who do not have lupus nephritis can include, for example, tissue biopsy samples, blood, plasma, serum, fecal samples, urine, cerebrospinal fluid, Pap smears or semen. A representative sample can include measurements from at least 10, 20, 30, 40, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, or more individuals.

[0069] The term "immunoglobulin" (Ig) is used interchangeably with "antibody" herein. The term "antibody" is used in the broadest sense herein, and specifically includes monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies) formed from at least two complete antibodies, antibody fragments (as long as they exhibit the desired biological activity) and antibody derivatives.

[0070] The basic 4-chain antibody unit is a heterotetrameric glycoprotein composed of two % identical light chains (L) and two % identical heavy chains (H). H and V L Paired together to form a single antigen binding site. For the structure and properties of different classes of antibodies, see, e.g., Basic and Clinical Immunology, 8th edition, Daniel P. Stites, Abba I. Terr and Tristram G. Parslow (eds.), Appleton & Lange, Norwalk, CT, 1994, p. 71 and Chapter 6.

[0071] The L chains from any vertebrate species can be divided into two clearly distinct types, called kappa ("κ") and lambda ("λ"), based on the amino acid sequence of their constant domains. Immunoglobulins can be divided into different classes or isotypes, depending on the amino acid sequence of the constant domain of their heavy chains (CH). There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, whose heavy chains are named alpha ("α"), delta ("δ"), epsilon ("ε"), gamma ("γ"), and muon ("μ"), respectively. Based on relatively minor differences in CH sequence and function, the gamma and alpha classes are further divided into subclasses (isotypes), for example, humans express the following subclasses: IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known and generally described, for example, in Abbas et al., Cellular and Molecular Immunology, 4th ed. (WB Saunders Co., 2000).

[0072] As used herein, the term "agent" describes any molecule (e.g., protein or drug) that has the ability to modulate synaptic loss, particularly through the complement pathway. Candidate agents also include genetic elements (e.g., antisense and RNAi molecules that inhibit C1q expression) and constructs encoding complement inhibitors (e.g., CD 59), etc. Candidate agents cover many chemical categories, although they are generally organic molecules including small organic compounds with a molecular weight greater than 50 and less than about 2,500 Daltons. Candidate agents contain functional groups necessary for structural interactions (especially hydrogen bonds) with proteins, and generally include at least one amine, carbonyl, hydroxyl or carboxyl group, preferably at least two functional chemical groups. Candidate agents generally include cyclic carbon or heterocyclic structures and / or aromatic or polyaromatic structures substituted by one or more of the above functional groups. Candidate agents are also found in biomolecules, including peptides, sugars, fatty acids, steroids, purines, pyrimidines, derivatives, structural analogs, or combinations thereof. Typically, multiple assay mixtures are run in parallel with different agent concentrations to obtain different responses to different concentrations. Typically, one of these concentrations is used as a negative control, i.e., the concentration is zero or below the detection level.

[0073] The "variable region" or "variable domain" of an antibody refers to the amino terminal domain of the heavy chain or light chain of an antibody. The variable domains of the heavy chain and light chain can be referred to as "V H ” and “V L These domains are usually the most variable parts of the antibody (relative to other antibodies of the same class) and contain the antigen binding site.

[0074] The term "variable" refers to certain segments of the variable domain in an antibody that differ greatly in sequence. The V domain mediates antigen binding and defines the specificity of a particular antibody to its specific antigen. However, variability is not evenly distributed over the entire span of the variable domain. In contrast, it is concentrated in three segments called hypervariable regions (HVRs) in the light and heavy chain variable domains. The more highly conserved parts of the variable domains are called framework regions (FRs). The variable domains of native heavy and light chains each contain four FR regions, which mostly adopt a β-folded configuration, connected by three HVRs, which form a loop connecting the β-sheet structure, and sometimes form a part of the β-sheet structure. The HVRs in each chain are tightly bound together by the FR region, and together with the HVRs from the other chain, contribute to the formation of the antigen binding site of the antibody (see Kabat et al., Sequences of Immunological Interest, Fifth Edition, National Institute of Health, Bethesda, MD (1991)). The constant domains are not directly involved in the binding of antibodies to antigens, but exhibit various effector functions, such as antibody involvement in antibody-dependent cellular toxicity.

[0075] As used herein, the term "CDR" or "complementarity determining region" refers to the non-contiguous antigen binding sites found within the variable regions of heavy and light chain polypeptides. Kabat et al., J. Biol. Chem. 252: 6609-6616 (1977); Kabat et al., USDept. of Health and Human Services, "Sequences of proteins of immunological interest" (1991) (also referred to herein as Kabat 1991); Chothia et al., J. Mol. Biol. 196: 901-917 (1987) (also referred to herein as Chothia 1987); and MacCallum et al., J. Mol. Biol. 262: 732-745 (1996) describe CDRs, where the definitions include overlaps or subsets of amino acid residues when compared to each other. However, the application of any definition to refer to the CDRs of an antibody or a grafted antibody or variants thereof is intended to be within the scope of the term as defined and used herein.

[0076] As used herein, the terms "CDR-L1", "CDR-L2" and "CDR-L3" refer to the first, second and third CDRs in the light chain variable region, respectively. As used herein, the terms "CDR-H1", "CDR-H2" and "CDR-H3" refer to the first, second and third CDRs in the heavy chain variable region, respectively. As used herein, the terms "CDR-1", "CDR-2" and "CDR-3" refer to the first, second and third CDRs in either chain variable region, respectively.

[0077] The term "monoclonal antibody" as used herein refers to an antibody obtained from a substantially homogeneous antibody population, i.e., the individual antibodies in the population are identical, except for possible naturally occurring mutations and / or post-translational modifications (e.g., isomerization, amidation) that may be present in small amounts. Monoclonal antibodies have a high degree of specificity (for a single antigenic site). In contrast to polyclonal antibody preparations that typically include different antibodies for different determinants (epitopes), each monoclonal antibody is directed to a single determinant on the antigen. In addition to its specificity, monoclonal antibodies are advantageous because they are typically synthesized by hybridoma cultures and are not contaminated by other immunoglobulins. The modifier "monoclonal" indicates the characteristics of an antibody obtained as a substantially homogeneous antibody population and should not be construed as requiring the antibody to be produced by any ad hoc method. For example, monoclonal antibodies used in accordance with the present disclosure can be prepared by a variety of techniques, including, for example, the hybridoma method (e.g., Kohler and Milstein., Nature, 256:495-97 (1975); Hongo et al., Hybridoma, 14(3):253-260 (1995); Harlow et al., Antibodies: A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988); Hammerling et al., Monoclonal Antibodies and T-Cell Immunofluorescence ... Hybridomas 563-681 (Elsevier, NY, 1981)), recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567), phage display technology (see, e.g., Clackson et al., Nature, 352:624-628 (1991); Marks et al., J. Mol. Biol. 222:581-597 (1992); Sidhu et al., J. Mol. Biol. 338(2):299-310 (2004); Lee et al., J. Mol. Biol. 340(5):1073-1093 (2004); Fellouse, Proc. Nat'l Acad. Sci. USA 101(34):12467-472 (2004); and Lee et al., J. Immunol. Methods 284(1-2):119-132 (2004) and techniques for producing human or human-like antibodies in animals having partial or complete human immunoglobulin loci or genes encoding human immunoglobulin sequences (see, e.g., WO 1998 / 24893; WO 1996 / 34096; WO 1996 / 33735; WO 1991 / 10741; Jakobovits et al., Proc. Nat'l Acad. Sci.USA 90:2551 (1993); Jakobovits et al., Nature 362:255-258 (1993); Bruggemann et al., Year in Immunol. 7:33 (1993); U.S. Pat. Nos. 5,545,807; 5,545,806; 5,569,825; 5,625,126; 5,633,425; and 5,661,016; Marks et al., Bio / Technology 10:779-783 (1992); Lonberg et al., Nature 368:856-859 (1994); Morrison, Nature 368:812-813 (1994); Fishwild et al., Nature Biotechnol. 14:845-851 (1996); Neuberger, Nature Biotechnol. 14:826 (1996); and Lonberg and Huszar, Intern. Rev. Immunol. 13:65-93 (1995). .

[0078] "Full-length antibodies" are usually heterotetrameric glycoproteins of about 150,000 daltons, which consist of two % identical light (L) chains and two % identical heavy (H) chains. Each light chain is linked to a heavy chain by a covalent disulfide bond, while the number of disulfide bonds between the heavy chains of different immunoglobulin isotypes varies. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has a variable domain (V) at one end. H ), followed by a number of constant domains. Each light chain has a variable domain at one end (V L ), and at the other end there is a constant domain; the constant domain of the light chain is aligned with the first constant domain of the heavy chain, and the light chain variable domain is aligned with the heavy chain variable domain. It is believed that specific amino acid residues form the interface between the light chain variable domain and the heavy chain variable domain.

[0079] The terms "full-length antibody," "intact antibody," and "whole antibody" are used interchangeably to refer to an antibody in substantially intact form, as opposed to an antibody fragment or antibody derivative. Specifically, whole antibodies include those having heavy and light chains that include an Fc region. The constant region may be a native sequence constant domain (e.g., a human native sequence constant domain) or an amino acid sequence variant thereof. In some cases, an intact antibody may have one or more effector functions.

[0080] An "antibody fragment" or "functional fragment" of an antibody comprises a portion of an intact antibody, preferably the antigen binding and / or variable region of an intact antibody, or the F region of an antibody that retains or has modified FcR binding ability. Examples of antibody fragments include Fab, Fab', F(ab')2, and Fv fragments; diabodies; and linear antibodies (see U.S. Pat. No. 5,641,870, Example 2; Zapata et al., Protein Eng. 8(10): 1057-1062 (1995)). Other examples of antibody fragments include antibody derivatives, such as single-chain antibody molecules, one-armed antibodies, antibodies with a single antigen binding arm, monovalent antibodies, and multispecific antibodies formed from antibody fragments.

[0081] The term "single-armed antibody" herein is used to encompass antibodies comprising a single antigen-binding arm. A single-armed antibody may comprise an antigen-binding arm and an Fc region, wherein the single antigen-binding arm comprises a light chain variable domain and a heavy chain variable domain; and the Fc region comprises a complex of a first Fc polypeptide and a second Fc polypeptide. In some embodiments, one (but not both) of the Fc polypeptides is an N-terminally truncated heavy chain. In some embodiments, the antibody may be a bivalent antibody—one arm binds C1q and the other arm binds another antigen. Depending on the other antigen, such an antibody will not cross-link and activate C1q.

[0082] As used herein, "an antibody having a single antigen binding arm" means an antibody comprising a single antigen binding arm and an Fc region, wherein the antigen binding arm comprises a light chain variable domain and a heavy chain variable domain. In some embodiments, the antibody further comprises an inactive antigen binding arm that cannot bind to an antigen, or the antibody comprises an arm that binds to a different antigen. In some embodiments, the Fc region comprises a complex of a first Fc polypeptide and a second Fc polypeptide.

[0083] An "antibody derivative" is any construct comprising the antigen-binding region of an antibody. Examples of antibody derivatives include single-chain antibody molecules, one-armed antibodies, antibodies with a single antigen-binding arm, monovalent antibodies, and multispecific antibodies formed from antibody fragments.

[0084] Papain digestion of antibodies produces two % identical antigen-binding fragments, called "Fab" fragments, and a residual "Fc" fragment, a name that reflects the ability to crystallize readily. The Fab fragment consists of an intact L chain and the variable region domain (V H ) and the first constant domain of a heavy chain (C H1) Composition. Each Fab fragment is monovalent in terms of antigen binding, i.e., it has a single antigen binding site. Pepsin treatment of an antibody produces a single large F(ab')2 fragment that is roughly equivalent to two disulfide-linked Fab fragments with different antigen binding activities and is still able to cross-link antigen. The Fab' fragment differs from the Fab fragment in that the C H The carboxyl terminus of the constant domain has several additional residues, including one or more cysteines from the antibody hinge region. Fab' in which the cysteine ​​residues of the constant domains have free thiol groups is referred to herein as Fab'-SH. F(ab')2 antibody fragments were initially produced in the form of Fab' fragment pairs that had hinge cysteines between the Fab' fragments. Other chemical couplings of antibody fragments are also known.

[0085] The Fc fragment comprises the carboxyl terminal portions of two H chains held together by disulfides. The effector functions of an antibody are determined by the sequence of the Fc region, which is also recognized by Fc receptors (FcR) found on certain types of cells.

[0086] The term "Fc region" is used herein to define the C-terminal region of an immunoglobulin heavy chain, including a native sequence Fc region and a variant Fc region. Although the boundaries of the Fc region of an immunoglobulin heavy chain may be different, the human IgG heavy chain Fc region is generally defined as extending from the amino acid residue at position Cys226 or from Pro230 to its carboxyl terminus. The C-terminal lysine (according to the EU numbering system, residue 447) in the Fc region can be removed, for example, during production or purification of antibodies or by recombinant engineering of the nucleic acid encoding the heavy chain of an antibody. Therefore, the composition of a complete antibody can include an antibody population in which all K447 residues are removed, an antibody population in which no K447 residue is removed, and an antibody population with and without an antibody mixture containing K447 residues. The native sequence Fc region suitable for antibodies of the present disclosure includes human IgG1, IgG2, IgG3, and IgG4.

[0087] A "native sequence Fc region" comprises an amino acid sequence that is % identical to the amino acid sequence of an Fc region found in nature. Native sequence human Fc regions include native sequence human IgG1 Fc regions (non-A and A allotypes); native sequence human IgG2 Fc regions; native sequence human IgG3 Fc regions; and native sequence human IgG4 Fc regions, as well as naturally occurring variants thereof.

[0088] A "variant Fc region" comprises an amino acid sequence that is distinguished from a native sequence Fc region amino acid sequence by at least one amino acid modification (preferably one or more amino acid substitutions). Preferably, the variant Fc region has at least one amino acid substitution compared to the native sequence Fc region or the Fc region of a parent polypeptide, for example, there are about one to about ten amino acid substitutions in the native sequence Fc region or the Fc region of a parent polypeptide, preferably about one to about five amino acid substitutions. The variant Fc region herein will preferably have at least about 80% homology with the native sequence Fc region and / or with the Fc region of a parent polypeptide, most preferably at least about 90% homology therewith, and more preferably at least about 95% homology therewith.

[0089] "Fc receptor" or "FcR" describes a receptor that binds to the Fc region of an antibody. A preferred FcR is a native sequence human FcR. In addition, a preferred FcR is an FcR that binds to IgG antibodies (gamma receptors) and includes receptors of the FcγRI, FcγRII and FcγRIII subclasses, including allelic variants and alternative splice forms of these receptors, FcγRII receptors including FcγRIIA ("activating receptor") and FcγRIIB ("inhibiting receptor"), which have similar amino acid sequences that differ primarily in their cytoplasmic domains. The activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif ("ITAM") in its cytoplasmic domain. The inhibitory receptor FcγRIIB contains an immunoreceptor tyrosine-based inhibition motif ("ITIM") in its cytoplasmic domain. (See, e.g., M. Annu. Rev. Immunol. 15: 203-234 (1997). FcRs are reviewed in Ravetch and Kinet, Annu. Rev. Immunol. 9: 457-92 (1991); Capel et al., Immunomethods 4: 25-34 (1994); and deHaas et al., J. Lab. Clin. Med. 126: 330-41 (1995). Other FcRs (including those to be identified in the future) are encompassed by the term "FcR". FcRs can also increase the serum half-life of antibodies.

[0090] The binding and serum half-life of a human FcRn high affinity binding polypeptide in vivo to FcRn can be determined, for example, in transgenic mice expressing human FcRn or transfected human cell lines or in primates to which polypeptides having variant Fc regions are administered. WO 2004 / 42072 (Presta) describes antibody variants with enhanced or reduced binding to FcRs. See also, for example, Shields et al., J. Biol. Chem. 9 (2): 6591-6604 (2001).

[0091] "Fv" is the smallest antibody fragment that contains a complete antigen recognition and antigen binding site. This fragment consists of a dimer of a heavy chain variable region domain and a light chain variable region domain in tight non-covalent association. From the folding of these two domains, six hypervariable loops (3 loops each in the H chain and L chain) are derived, which provide amino acid residues for antigen binding and give the antibody antigen binding specificity. However, even a single variable domain (or half of an Fv containing only three HVRs specific for an antigen) has the ability to recognize and bind to an antigen, although its affinity is lower than that of the complete binding site.

[0092] "Single-chain Fv", also abbreviated as "sFv" or "scFv", is an antibody fragment comprising the VH and VL antibody domains linked into a single polypeptide chain. Preferably, the sFv polypeptide also comprises a V H With V L A polypeptide linker between domains that enables sFv to form the structure required for antigen binding. For a review of sFv, see Plückthun, The Pharmacology of Monoclonal Antibodies, Vol. 113, Rosenburg and Moore, eds., Springer-Verlag, New York, pp. 269-315 (1994).

[0093] The term "diabody" refers to a H With V L Small antibody fragments prepared by constructing sFv fragments (see previous paragraph) with short linkers (about 5-10 residues) between the domains, so that interchain pairing of the V domains is achieved rather than intrachain pairing, thereby generating bivalent fragments, i.e., fragments with two antigen-binding sites. Bispecific diabodies are heterodimers of two "crossover" sFv fragments, in which the V domains of the two antibodies are H and V L The domains are present on different polypeptide chains. Diabodies are described in detail in, for example, EP 404,097; WO 1993 / 011161; WO / 2009 / 121948; WO / 2014 / 191493; Hollinger et al., Proc. Nat'l Acad. Sci. USA 90:6444-48 (1993).

[0094] As used herein, "chimeric antibody" refers to an antibody (immunoglobulin) in which a portion of the heavy chain and / or light chain is identical or homologous to the corresponding sequence in an antibody derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain is identical or homologous to the corresponding sequence in an antibody derived from another species or belonging to another antibody class or subclass, as long as it exhibits the desired biological activity (U.S. Pat. No. 4,816,567; and Morrison et al., Proc. Nat'l Acad. Sci. USA, 81:6851-55 (1984)). The chimeric antibodies of interest herein include Antibodies wherein the antigen binding region of the antibody is derived from an antibody produced by, for example, immunizing a macaque with an antigen of interest. As used herein, "humanized antibodies" are a subset of "chimeric antibodies"

[0095] The "humanized" form of a non-human (e.g., mouse) antibody is a chimeric antibody containing minimal sequences derived from non-human immunoglobulins. In some embodiments, a humanized antibody is a human immunoglobulin (receptor antibody), wherein the residues from the HVR of the receptor are replaced by residues from the HVR of a non-human species (donor antibody) (e.g., mouse, rat, rabbit, or non-human primate) with the desired specificity, affinity, and / or ability. In some cases, the FR residues of a human immunoglobulin are replaced by corresponding non-human residues. In addition, a humanized antibody may be included in a receptor antibody or in a residue not found in a donor antibody. These modifications may be performed to further improve the performance of the antibody, such as binding affinity. In general, a humanized antibody will include substantially all of at least one, usually two variable domains, wherein all or substantially all of the hypervariable loops correspond to the hypervariable loops of a non-human immunoglobulin sequence, and all or substantially all of the FR regions are those of a human immunoglobulin sequence, but the FR region may include one or more individual FR residue substitutions, which may improve antibody performance, such as binding affinity, isomerization, immunogenicity, etc. The number of these amino acid substitutions in the FR is usually no more than 6 in the H chain and no more than 3 in the L chain. The humanized antibody optionally also comprises at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For additional details, see, e.g., Jones et al., Nature 321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992). See also, e.g., Vaswani and Hamilton, Ann. Allergy, Asthma & Immunol. 1: 105-115 (1998); Harris, Biochem. Soc. Transactions 23: 1035-1038 (1995); Hurle and Gross, Curr. Op. Biotech. 5: 428-433 (1994); and U.S. Pat. Nos. 6,982,321 and 7,087,409.

[0096] A "human antibody" is an antibody having an amino acid sequence corresponding to the amino acid sequence of an antibody produced by a human, and / or an antibody prepared using any of the techniques disclosed herein for preparing human antibodies. This definition of a human antibody specifically excludes humanized antibodies comprising non-human antigen binding residues. Human antibodies can be produced using various techniques known in the art, including phage display libraries. Hoogenboom and Winter, J. Mol. Biol., 227: 381 (1991); Marks et al., J. Mol. Biol., 222: 581 (1991). Also useful for preparing human monoclonal antibodies are methods described in Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1985); Boerner et al., J. Immunol., 147 (1): 86-95 (1991). See also van Dijk and van de Winkel, Curr. Opin. Pharmacol. 5: 368-74 (2001). Human antibodies can be prepared by administering an antigen to a transgenic animal that has been modified to produce such antibodies in response to antigenic challenge but whose endogenous loci have been disabled, such as an immunized xenogeneic mouse (refer to XENOMOUSE TM For human antibodies generated by human B cell hybridoma technology, see, e.g., U.S. Patent Nos. 6,075,181 and 6,150,584). For human antibodies generated by human B cell hybridoma technology, see, e.g., Li et al., Proc. Nat'l Acad. Sci. USA, 103:3557-3562 (2006).

[0097] The term "hypervariable region", "HVR" or "HV" as used herein refers to the region of the antibody variable domain whose sequence is highly variable and / or forms a structurally defined loop. Typically, an antibody comprises six HVRs, three in VH (H1, H2, H3) and three in VL (L1, L2, L3). In natural antibodies, H3 and L3 show the greatest diversity among the six HVRs, and H3 in particular is considered to play a unique role in conferring good specificity to antibodies. See, for example, Xu et al., Immunity 13:37-45 (2000); Johnson and Wu, Methods in Molecular Biology 248:1-25 (Lo ed., Human Press, Totowa, NJ, 2003)). In fact, naturally occurring camelid antibodies consisting only of heavy chains are functional and stable in the absence of light chains. See, eg, Hamers-Casterman et al., Nature 363:446-448 (1993) and Sheriff et al., Nature Struct. Biol. 3:733-736 (1996).

[0098] Many HVR descriptions are in use and are included in this article. HVRs as Kabat complementary determining regions (CDRs) are based on the variability of sequences and are the most commonly used (Kabat et al., supra). Chothia refers to the position of the structural loop (Chothia and Lesk J.Mol.Biol.196:901-917 (1987)). AbM HVRs represent a compromise between Kabat CDRs and Chothia structural loops and are used by Oxford Molecular's AbM antibody modeling software. "Contact" HVRs are based on the analysis of available complex crystal structures.

[0099] The residues from each of these HVRs are shown below.

[0100]

[0101] HVRs may include the following "extended HVRs": 24-36 or 24-34 (L1), 46-56 or 50-56 (L2), and 89-97 or 89-96 (L3) in VL, 26-35 (H1), 50-65 or 49-65 (preferred embodiments) (H2), and 93-102, 94-102, or 95-102 (H3) in VH. For each of these extended HVR definitions, the variable domain residues are numbered according to Kabat et al., supra.

[0102] "Framework" or "FR" residues are those variable domain residues other than the HVR residues as herein defined.

[0103] The phrase "variable domain residue numbering as in Kabat" or "amino acid position numbering as in Kabat" and variants thereof refer to the numbering system used for the heavy chain variable domain or light chain variable domain of the antibody compilation in Kabat et al., supra. Using this numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids, corresponding to a shortening or insertion of a FR or HVR of the variable domain. For example, a heavy chain variable domain may include a single amino acid insertion after residue 52 of H2 (residue 52a according to Kabat) and an inserted residue after heavy chain FR residue 82 (e.g., residues 82a, 82b, and 82c, etc. according to Kabat). For a given antibody, the Kabat numbering of the residues can be determined by aligning the homologous region of the antibody sequence with the "standard" Kabat numbering sequence.

[0104] When referring to residues in the variable domain (approximately residues 1-107 of the light chain and residues 1-113 of the heavy chain), the Kabat numbering system is generally used (e.g., Kabat et al., Sequences of Immunological Interest. 5th Edition Public Health Service, National Institutes of Health, Bethesda, Md. (1991)). When referring to residues in the constant region of the immunoglobulin heavy chain, the "EU numbering system" or "EU index" is generally used (e.g., Kabat et al., EU index reported in supra). "EU index as in Kabat" refers to the residue numbering of human IgG1 EU antibodies. Unless otherwise specified herein, reference to residue numbering in antibody variable domains refers to residue numbering by the Kabat numbering system. Unless otherwise specified herein, reference to residue numbering in antibody constant domains refers to residue numbering by the EU numbering system (see, e.g., U.S. Patent Publication No. 2010-280227).

[0105] As used herein, "acceptor human framework" is a framework comprising an amino acid sequence of a VL or VH framework derived from a human immunoglobulin framework or a human consensus framework. An acceptor human framework "derived from" a human immunoglobulin framework or a human consensus framework may comprise an amino acid sequence that is % identical to it, or it may contain pre-existing amino acid sequence changes. In some embodiments, the number of pre-existing amino acid changes is 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. When pre-existing amino acid changes are present in VH, it is preferred that these changes occur only at three, two or one positions in positions 71H, 73H and 78H; for example, the amino acid residues at those positions may be 71A, 73T and / or 78A. In some embodiments, the VL acceptor human framework sequence is % identical to the VL human immunoglobulin framework sequence or the human consensus framework sequence.

[0106] "Human consensus framework" is a framework that represents the amino acid residues that are most commonly present in a selection of human immunoglobulin VL or VH framework sequences. Typically, the selection of human immunoglobulin VL or VH sequences is from a subgroup of variable domain sequences. Typically, the subgroup of sequences is a subgroup such as Kabat et al., Sequences of Proteins of Immunological Interest, 5th Edition Public Health Service, National Institutes of Health, Bethesda, MD (1991). Examples include that for VL, the subgroup may be a subgroup κI, κII, κIII or κIV such as Kabat et al., supra. In addition, for VH, the subgroup may be a subgroup I, subgroup II or subgroup III such as Kabat et al., supra.

[0107] "Amino acid modification" at a specific position refers to the substitution or deletion of a specific residue, or the insertion of at least one amino acid residue near a specific residue. Insertion "adjacent" a specific residue refers to insertion within one to two residues thereof. Insertion can be at the N-terminus or C-terminus of a specific residue. The preferred amino acid modification herein is substitution.

[0108] An "affinity matured" antibody refers to an antibody that has one or more changes in one or more of its HVRs that result in an improved affinity of the antibody for the antigen compared to a parent antibody that does not have those changes. In some embodiments, affinity matured antibodies have nanomolar or even picomolar affinities for the target antigen. Affinity matured antibodies are produced by methods known in the art. For example, Marks et al., Bio / Technology 10:779-783 (1992) describe affinity maturation by VH and VL domain shuffling. Random mutagenesis of HVR and / or framework residues is described, e.g., in Barbas et al. Proc Nat. Acad. Sci. USA 91:3809-3813 (1994); Schier et al. Gene 169:147-155 (1995); Yelton et al. J. Immunol. 155:1994-2004 (1995); Jackson et al., J. Immunol. 154(7):3310-9 (1995); and Hawkins et al., J. Mol. Biol. 226:889-896 (1992).

[0109] As used herein, the term "specific recognition" or "specific binding" refers to a measurable and repeatable interaction, such as attraction or binding between a target and an antibody, which determines the presence of a target in the presence of a heterogeneous population of molecules, including biomolecules. For example, an antibody that specifically or preferentially binds to a target or epitope is an antibody that binds to a target or epitope with greater affinity, avidity, greater ease, and / or greater duration than it binds to other targets or other epitopes of a target. It is also understood that, for example, an antibody (or portion) that specifically or preferentially binds to a first target may or may not specifically or preferentially bind to a second target. Thus, "specific binding" or "preferential binding" does not necessarily require (but it may include) exclusive binding. An antibody that specifically binds to a target may have at least about 10 3 M- 1 or 10 4 M- 1 , sometimes about 10 5 M- 1 or 10 6 M- 1 , in other cases about 10 6 M- 1 or 10 7 M- 1 , about 10 8 M- 1 Up to 10 9 M- 1 or about 10 10 M- 1 Up to 10 11 M-1 or higher association constant. A variety of immunoassay formats can be used to select antibodies that specifically immunoreact with a particular protein. For example, solid phase ELISA immunoassays are routinely used to select monoclonal antibodies that specifically immunoreact with a protein. For a description of immunoassay formats and conditions that can be used to determine specific immunoreactions, see, for example, Harlow and Lane (1988) Antibodies, A Laboratory Manual, Cold Spring Harbor Publications, New York.

[0110] As used herein, "identity" means that at any particular position of the aligned sequences, the amino acid residues between the sequences are % identical. As used herein, "similarity" indicates that at any particular position of the aligned sequences, the amino acid residues between the sequences are of similar type. For example, leucine can replace isoleucine or valine. Other amino acids that can often be substituted for each other include, but are not limited to:

[0111] - Phenylalanine, tyrosine and tryptophan (amino acids with aromatic side chains);

[0112] - lysine, arginine and histidine (amino acids with basic side chains);

[0113] - Aspartic acid and glutamic acid (amino acids with acidic side chains);

[0114] - Asparagine and glutamine (amino acids with amide side chains); and

[0115] - Cysteine ​​and methionine (amino acids with sulfur-containing side chains).

[0116] The degree of identity and similarity can be readily calculated (see, e.g., Computational Molecular Biology, Lesk, AM, ed., Oxford University Press, New York, 1988; Biocomputing. Informatics and Genome Projects, Smith, DW, ed., Academic Press, New York, 1993; Computer Analysis of Sequence Data, Part 1, Griffin, AM and Griffin, HG, eds., Humana Press, New Jersey, 1994; Sequence Analysis in Molecular Biology, von Heinje, G., Academic Press, 1987; and Sequence Analysis Primer, Gribskov, M. and Devereux, J., eds., M Stockton Press, New York, 1991).

[0117] As used herein, an "interaction" between a complement protein and a second protein encompasses, but is not limited to, protein-protein interactions, physical interactions, chemical interactions, binding, covalent binding, and ionic binding. As used herein, an antibody "inhibits" an interaction between two proteins when the antibody disrupts, reduces, or completely eliminates the interaction between the two proteins. When an antibody or fragment thereof of the present disclosure binds to one of the two proteins, the antibody or fragment thereof "inhibits" an interaction between the two proteins.

[0118] A "blocking" antibody, "antagonist" antibody, "inhibitory" antibody, or "neutralizing" antibody is an antibody that inhibits or reduces one or more biological activities of the antigen to which it binds, such as interaction with one or more proteins. In some embodiments, a blocking antibody, antagonist antibody, inhibitory antibody, or "neutralizing" antibody substantially or completely inhibits one or more biological activities or interactions of the antigen.

[0119] The term "inhibitor" refers to a compound that is able to inhibit the biological function of a target biomolecule (e.g., mRNA or protein) by reducing the activity or expression of the target biomolecule. An inhibitor can be an antibody, a small molecule, or a nucleic acid molecule. The term "antagonist" refers to a compound that binds to a receptor and blocks or inhibits the biological response of the receptor. The term "inhibitor" may also refer to an "antagonist"

[0120] Antibody "effector functions" refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary with the antibody isotype.

[0121] As used herein, the term "affinity" refers to the equilibrium constant that two reagents (e.g., antibody and antigen) are reversibly combined, and is expressed as a dissociation constant (KD). Affinity can be at least 1 times, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 20 times, at least 30 times, at least 40 times, at least 50 times, at least 60 times, at least 70 times, at least 80 times, at least 90 times, at least 100 times, or at least 1,000 times or more than the affinity of the antibody to an unrelated amino acid sequence. The affinity of the antibody to a target protein can be, for example, about 100 nanomoles (nM) to about 0.1 nM, about 100 nM to about 1 picomoles (pM) or about 100 nM to about 1 femtomoles (fM) or higher. As used herein, the term "affinity" refers to the resistance of a complex of two or more agents to dissociate upon dilution. With respect to antibodies and / or antigen-binding fragments, the terms "immunoreactivity" and "preferential binding" are used interchangeably herein.

[0122] The term "binding" refers to a direct association between two molecules due to, for example, covalent, electrostatic, hydrophobic, and ionic and / or hydrogen bonding interactions, including interactions such as salt bridges and water bridges. For example, a subject anti-C1s antibody specifically binds to an epitope within the complement C1s protein. "Specific binding" refers to an affinity of at least about 10 -7 M or larger, such as 5×10 -7 M, 10 -8 M, 5×10 -8 M and greater. "Non-specific binding" refers to an affinity less than about 10 -7 M, for example, 10 -6 M, 10 -5 M, 10 -4 M etc. affinity binding.

[0123] The term "k on ” refers to the rate constant for the association of antibody with antigen.

[0124] The term "k off ” refers to the rate constant for the dissociation of an antibody from the antibody / antigen complex.

[0125] The term "K D ” refers to the equilibrium dissociation constant of the antibody-antigen interaction.

[0126] As used herein, "percentage (%) of amino acid sequence identity" and "homology" with respect to peptide, polypeptide or antibody sequences refers to the percentage of amino acid residues in a candidate sequence that are identical to the amino acid residues in a particular peptide or polypeptide sequence, after alignment of the sequences and introduction of gaps (if necessary) to achieve the maximum percentage of sequence identity, and does not take into account any conservative substitutions as part of the sequence identity. Alignment for determination of percentage of amino acid sequence identity can be achieved in a variety of ways within the skill of the art, for example, using publicly available computer software such as BLAST, BLAST-2, ALIGN or MEGALIGN TM (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms known in the art needed to achieve maximal alignment over the full length of the sequences being compared.

[0127] "Biological sample" covers a variety of sample types obtained from an individual, and can be used for diagnosis or monitoring determination. The definition covers liquid samples of blood and other biological sources, solid tissue samples (such as biopsy specimens or tissue cultures or cells derived therefrom) and their offspring. The definition also includes samples processed in any way after acquisition, such as by treating with reagents, dissolving or enriching certain components, such as polynucleotides. The term "biological sample" covers clinical samples, and also includes cultured cells, cell supernatants, cell lysates, serum, plasma, biological fluids and tissue samples. The term "biological sample" includes urine, saliva, cerebrospinal fluid, interstitial fluid, eye fluid, synovial fluid, blood components (such as plasma and serum), etc. The term "biological sample" also includes solid tissue samples, tissue culture samples and cell samples.

[0128] "Host cell" includes a single cell or cell culture that can be or has been a recipient of a vector for incorporating a polynucleotide insert. Host cells include the progeny of a single host cell, and the progeny are not necessarily completely identical (in morphology or genomic DNA complement) to the original parent cell due to natural, accidental, or intentional mutation. Host cells include cells transfected in vivo with a polynucleotide of the disclosure.

[0129] As used herein, "carrier" includes a pharmaceutically acceptable carrier, excipient, or stabilizer that is nontoxic to cells or mammals exposed thereto at the dosages and concentrations used. Typically, a physiologically acceptable carrier is a pH buffered aqueous solution. Examples of physiologically acceptable carriers include buffers such as phosphates, citrates, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptides; proteins such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and / or nonionic surfactants such as TWEEN TM , polyethylene glycol (PEG) and PLURONICS TM .

[0130] As used herein, the term "pathogenic anti-C1q antibody" or "pathogenic anti-C1q antibody" or "PACA" or "PACAs" refers to an endogenous autoantibody to C1q that selectively recognizes a neo-epitope in the collagen tail of C1q when it is bound to a substrate, thereby recruiting additional C1q. PACAs are composed of four IgG subclasses, IgG1, IgG2, IgG3, and IgG4, referred to as PACA1, PACA2, PACA3, and PACA4, respectively. PACAs recognize the collagen tail of C1q when it is bound to a substrate and recruit additional C1q through their Fc region, thereby enhancing C1q activity. Without wishing to be bound by theory, when PACAs bind within the glomerulus to C1q that has been brought to the site by other types of glomerular reactive autoantibodies, they can amplify glomerular damage.

[0131] The term "subject" as used herein refers to a living mammal and can be used interchangeably with the term "patient". Examples of mammals include, but are not limited to, any member of the class of mammals: humans; non-human primates, such as chimpanzees and other apes and monkey species; livestock, such as cattle, horses, sheep, goats, pigs; domestic animals, such as rabbits, dogs and cats; laboratory animals, including rodents, such as rats, mice and guinea pigs, etc. The terms do not denote a particular age or sex.

[0132] As used herein, the terms "treating" or "treatment" include alleviating a disorder, arresting a disorder, or reversing the symptoms, clinical signs, or underlying pathology of a disorder, to stabilize or improve a subject's disorder, or to reduce the likelihood that a subject's disorder will worsen, as if the subject were not receiving treatment.

[0133] The term "therapeutically effective amount" of a compound with respect to the subject treatment methods refers to an amount of the compound in a formulation that, when administered as part of a desired dosing regimen (to a mammal, preferably a human), alleviates symptoms, ameliorates symptoms, or slows the onset of a disease condition, according to clinically acceptable standards for the condition or disorder to be treated or for cosmetic purposes, e.g., at a reasonable benefit / risk ratio applicable to any drug treatment. A therapeutically effective amount herein may vary according to factors such as the disease state, age, sex, and weight of the patient, and the ability of the antibody to elicit a desired response in the individual.

[0134] As used herein, an individual who is "at risk" of developing a particular disease, disorder, or condition may or may not have detectable disease or disease symptoms, and may or may not have detectable disease or disease symptoms prior to the methods of treatment described herein. "At risk" means that the individual has one or more risk factors, which are measurable parameters associated with the development of a particular disease, disorder, or condition, as known in the art. An individual who has one or more of these risk factors has a higher likelihood of developing a particular disease, disorder, or condition than an individual who does not have one or more of these risk factors.

[0135] "Chronic" administration refers to administration in a continuous rather than acute manner, thereby maintaining the initial therapeutic effect (activity) over an extended period of time. "Intermittent" administration refers to treatment that is not continuously administered without interruption, but is cyclical / periodic in nature.

[0136] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar to or equivalent to those described herein may also be used in the practice or testing of the present invention, preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials associated with the cited publications. For example, Sambrook et al., Molecular Cloning: A Laboratory Manual 3rd Edition (2001) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY; Current Protocols in Molecular Biology (ed. FMAusubel et al. (2003)); the series Methods in Enzymology (Academic Press, Inc.): PCR 2: A Practical Approach (edited by MJMacPherson, BD Hames and GRTaylor (1995)), Harlow and Lane (edited (1988)) Antibodies, A Laboratory Manual, and Animal Cell Culture (edited by RI Freshney, (1987)); Oligonucleotide Synthesis (edited by MJGait, 1984); Methods in Molecular Biology, Humana Press; CellBiology: A Laboratory Notebook (edited by JECellis, 1998) Academic Press; Animal CellCulture (RI Freshney), ed., 1987); Introduction to Cell and Tissue Culture (JPMather and PE Roberts, 1998) Plenum Press; Cell and Tissue Culture: Laboratory Procedures (A. Doyle, JBGffiths and DG Newell, ed., 1993-8) J. Wiley and Sons; Handbook of Experimental Immunology (DMWeir and CCBlackwell (ed.); Gene TransferVectors for Mammalian Cells (JMMiller and MPCalos, 1987); PCR: The PolymeraseChain Reaction, (Mullis et al., 1994); Current Protocols in Immunology (JEColigan et al., 1991); Short Protocols in Molecular Biology (Wiley and Sons, 1999); Immunobiology (CA Janeway and P. Travers, 1997); Antibodies (P. Finch, 1997); Antibodies: A Practical Approach (edited by D. Catty, IRL Press, 1988-1989); Monoclonal Antibodies: A Practical Approach (edited by P. Shepherd and C. Dean, Oxford University Press, 2000); Using Antibodies: A Laboratory Manual (E. Harlow and D. Lane (Cold Spring Harbor Laboratory The widely used methods described in The Antibodies (M. Zanetti and JD Capra, eds., Harwood Academic Publishers, 1995); and Cancer: Principles and Practice of Oncology (VT DeVita et al., eds., JB Lippincott Company, 1993).

[0137] C1q inhibitors

[0138] The inhibitor of the classical complement pathway may be a C1q inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0139] The anti-C1q antibodies disclosed herein are potent inhibitors of C1q.

[0140] C1q is a 460 kDa polymeric protein consisting of 18 polypeptide chains (6 C1q A chains, 6 C1q B chains, and 6 C1q C chains). The C1r and C1s complement proteins bind to the C1q tail region to form the C1 complex (C1qr2s2).

[0141] Suitable inhibitors include antibodies that bind to complement factor C1q and / or C1q in the C1 complex of the classical complement activation pathway. The binding complement factor can be derived from, without limitation, any organism with a complement system, including any mammalian organism, such as humans, mice, rats, rabbits, monkeys, dogs, cats, cows, horses, camels, sheep, goats or pigs.

[0142] As used herein, "C1 complex" refers to a protein complex that may include, but is not limited to, one C1q protein, two C1r proteins, and two C1s proteins (e.g., 2 s 2 ).

[0143] As used herein, "complement factor C1q" refers to both the wild-type sequence and naturally occurring variant sequences.

[0144] A non-limiting example of a complement factor C1q recognized by the antibodies of the present disclosure is human C1q, comprising three polypeptide chains A, B and C:

[0145] C1q, chain A (homo sapiens), accession number protein

[0146] Database: NP_057075.1; GenBank ID: NM_015991:

[0147] >gi|7705753|ref|NP_057075.1|Component C1q

[0148] Subunit A precursor [Homo sapiens]

[0149] (SEQ ID NO:1)

[0150] MEGPRGWLVLCVLAISLASMVTEDLCCRAPDGKKGEAGRPGRRGRPGLKGEQGEPGAPGIRTGIQGLKGDQGEPGPSGNPGKVGYPGPSGPLGARGIPGIKGTKGSPGNIKDQPRPAFSAIRRN PPMGGNVVIFDTVITNQEEPYQNHSGRFVCTVPGYYYFTFQVLSQWEICLSIVSSSSRGQVRRSLGFCDTTNKGLFQVVSGGMVLQLQQGDQVWVEKDPKKGHIYQGSEADSVFSGFLIFPSA.

[0151] C1q, chain B (Homo sapiens), accession number protein

[0152] Database: NP_000482.3; GenBank ID: NM_000491.3:

[0153] >gi|87298828|ref|NP_000482.3|Component Clq

[0154] Subunit B precursor [Homo sapiens]

[0155] (SEQ ID NO:52)

[0156] MMMKIPWGSIPVLMLLLLGLIDISQAQLSCTGPPAIPGIPGIPGTPGPDGQPGTPGIKGEKGLPGLAGDHGEFGEKGDPGIPGNPGKVGPKGPMGPKGGPGAPGAPGPKGESGDYKATQKIAFSAT RTINVPLRRDQTIRFDHVITNMNNNYEPRSGKFTCKVPGLYYFTYHASSRGNLCVNLMRGRERAQKVVTFCDYAYNTFQVTTGGMVLKLEQGENVFLQATDKNSLLGMEGANSIFSGFLLFPDMEA.

[0157] C1q, chain C (Homo sapiens), accession number protein

[0158] Database: NP_001107573.1; GenBank ID:

[0159] NM_001114101.1:

[0160] >gi|166235903|ref|NP_001107573.1|Component C1q

[0161] Subunit C precursor [Homo sapiens]

[0162] (SEQ ID NO:53)

[0163] MDVGPPSSLPHLGLKLLLLLLPLRGQANTGCYGIPGMPGLPGAPGKDGYDGLPPGPKGEPGIPAIPGIRGPKGQKGEPGLPGHPGKNGPMGPPGMPGVPGPMGIPGEPGEEGRYKQKFQSVFT VTRQTHQPPAPNSLIRFNAVLTNPQGDYDTSTGKFTCKVPGLYYFVYHASHTANLCVLLYRSGVKVVTFCGHTSKTNQVNSGGVLLRLQVGEEVWLAVNDYYDMVGIQGSDSVFSGFLLFPD.

[0164] Thus, the anti-C1q antibodies of the present disclosure can bind to polypeptide chain A, polypeptide chain B, and / or polypeptide chain C of the C1q protein. In some embodiments, the anti-C1q antibodies of the present disclosure bind to polypeptide chain A, polypeptide chain B, and / or polypeptide chain C of human C1q or a homolog thereof, such as mouse, rat, rabbit, monkey, dog, cat, cow, horse, camel, sheep, goat, or pig C1q. In some embodiments, the anti-C1q antibody is a human antibody, a humanized antibody, or a chimeric antibody.

[0165] Other anti-C1q antibodies suitable for binding to C1q proteins are well known in the art and include, for example, antibodies Cat#: AF2379, AF1696, MAB1696, and MAB23791 (R&D System); NBP1-87492, NB100-64420, H00000712-B01P, H00000712-D01P, and H00000712-D01 (Novus Biologicals); MA1-83963, MA1-40311, PA5-14208, PA5-29586, and PA1-36177 (ThermoFisher Scientific); ab71940, ab11861, ab4223, ab72355, ab182451, ab46191, ab227072, ab182940, ab216979, and ab235454 (abcam), etc. In addition, a variety of siRNA, shRNA, CRI for reducing C1q expression SPR constructs can be found in the commercial product lists of the above-mentioned companies, such as SiRNA product #sc-43651, sc-44962, sc-105153, sc-141842; ShRNA product #sc-43651-SH, sc-43651-V, sc-44962-SH, sc-44962-V, sc-105153-SH, sc-105153-V, sc-141842-SH, sc-141842-V; CRISPR product #sc -419385, sc-419385-HDR, sc-419385-NIC, sc-419385-NIC-2, sc-402156, sc-402156-KO-2, sc-404309, sc-40430 9-HDR, sc-404309-NIC, sc-404309-NIC-2, sc-419386, sc-419386-HDR, sc-419386-NIC, sc-419386-NIC-2 (Santa Cruz Biotechnology et al.).

[0166] The light chain and heavy chain hypervariable region sequences and variable domain sequences of antibody M1 (Mab1) (from U.S. Pat. No. 9,708, No. 394 is incorporated by reference)

[0167] Using standard techniques, the nucleic acid and amino acid sequences encoding the light chain variable domain and heavy chain variable domain of antibody M1 were determined. The amino acid sequence of the light chain variable domain of antibody M1 is:

[0168]

[0169] The hypervariable region (HVR) of the light chain variable domain is marked in bold and underlined. In some embodiments, the HVR-L1 of the M1 light chain variable domain has the sequence RASKSINKYLA (SEQ ID NO: 5), the HVR-L2 of the M1 light chain variable domain has the sequence SGSTLQS (SEQ ID NO: 6), and the HVR-L3 of the M1 light chain variable domain has the sequence QQHNEYPLT (SEQ ID NO: 7).

[0170] The amino acid sequence of the heavy chain variable domain of antibody M1 is:

[0171]

[0172] The hypervariable region (HVR) of the heavy chain variable domain is marked in bold and underlined. In some embodiments, the HVR-H1 of the M1 heavy chain variable domain has the sequence GYHFTSYWMH (SEQ ID NO: 9), the HVR-H2 of the M1 heavy chain variable domain has the sequence VIHPNSGSINYNEKFES (SEQ ID NO: 10), and the HVR-H3 of the M1 heavy chain variable domain has the sequence ERDSTEVLP MDY (SEQ ID NO: 11).

[0173] The nucleic acid sequence encoding the light chain variable domain was determined to be:

[0174] GATGTCCAGATAACCCAGTCTCCATCTTATCTTGCTGCATCTCCTGGAGAAACCATTACTATTAATTGCAGGGCAAGTAAGAGCATTAACAAATATT TAGCCTGTGTCAAGAGAAACCTGGGAAAACTAATAAGCTTCTTATCTACTCTGGATCCACTTTGCAATCTGGAATTCCATCAAGGTTCAGTGGCAGTGGATCTGGTACAGATTTCACTCTCACCATCAGTAGCCTGGAGCCTGAAGATTTTGCAATGTATTACTGTCAACAACATAATGAATACCCGCTCACGTTCGGTGCTGGGACCAAGCTGGAGCTGAAA (SEQ ID NO: 12).

[0175] The nucleic acid sequence encoding the heavy chain variable domain was determined to be:

[0176] CAGGTCCAACTGCAGCAGCCTGGGGCTGAGCTGGTAAAGCCTGGGGCTTCAGTGAAGTTGTCCTGCAAGTCTTCTGGCTACCATTTCACCAGCTACTGGATGCACTGGGTGAAGCAGAGGCCTGGACAAGGCCTTGAGTGGATTGGAGTGATTCATCCTAATAGTGGTAGTATTAACTACAAT GAGAAGTTCGAGAGCAAGGCCACACTGACTGTAGACAAATCCTCCAGCACAGCCTACATGCAACTCAGCAGCCTGACATCTGAGGACTCGGCGGTCTATTATTGTGCAGGAGAGAGAGATTCTACGGAGGTTCTCCCTATGGACTACTGGGGTCAAGGAACCTCAGTCACCGTCTCCTCA(SEQ IDNO:13).

[0177] Mab1-Fab is the Fab of the Mab1 (M1) antibody.

[0178] Mab3 is a mouse anti-C1q antibody derived from Mab 1 and optimized for mouse experiments.

[0179] Material preservation

[0180] The following materials have been deposited under the Budapest Treaty with the American Type Culture Collection, ATCC Patent Depository, 10801 University Blvd., Manassas, Va. 20110-2209, USA (ATCC):

[0181]

[0182] The hybridoma cell line producing the M1 antibody (Mouse Hybridoma C1qM1 7788-1(M)051613) has been deposited with the ATCC under conditions that ensure availability of culture during the pendency of a patent application for a period of 30 years, or 5 years after the most recent request, or the effective life of the patent, whichever is longer. If the deposit becomes unavailable during that period, the deposit will be replaced. The deposit is available as required by foreign patent laws in countries in which the counterpart or progeny of the subject application is filed. It should be understood, however, that the availability of the deposit does not constitute a license to practice the subject invention in derogation of patent rights granted by governmental action.

[0183] Disclosed herein are methods of administering an anti-C1q antibody comprising a light chain variable domain and a heavy chain variable domain. The antibody may bind at least to human C1q, mouse C1q, or rat C1q. The antibody may be a humanized antibody, a chimeric antibody, or a human antibody. The antibody may be a monoclonal antibody, an antibody fragment thereof, and / or an antibody derivative thereof. The light chain variable domain comprises HVR-L1, HVR-L2, and HVR-L3 of the monoclonal antibody M1 produced by the hybridoma cell line deposited with accession number PTA-120399. The heavy chain variable domain comprises HVR-H1, HVR-H2, and HVR-H3 of the monoclonal antibody M1 produced by the hybridoma cell line deposited with ATCC accession number PTA-120399.

[0184] In some embodiments, the amino acid sequences of the light chain variable domain and the heavy chain variable domain comprise one or more of SEQ ID NO: 5 of HVR-L1, SEQ ID NO: 6 of HVR-L2, SEQ ID NO: 7 of HVR-L3, SEQ ID NO: 9 of HVR-H1, SEQ ID NO: 10 of HVR-H2, and SEQ ID NO: 11 of HVR-H3.

[0185] The antibody may comprise a light chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NO: 4, preferably while retaining HVR-L1 RASKSINKYLA (SEQ ID NO: 5), HVR-L2 SGSTLQS (SEQ ID NO: 6) and HVR-L3 QQHNEYPLT (SEQ ID NO: 7). The antibody may comprise a heavy chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NO: 8, preferably while retaining HVR-H1 GYHFTSYWMH (SEQ ID NO: 9), HVR-H2 VIHPNSGSINYNEKFES (SEQ ID NO: 10) and HVR-H3 ERDSTEVL PMDY (SEQ ID NO: 11).

[0186] Disclosed herein are methods of administering anti-Clq antibodies that inhibit the interaction between Clq and autoantibodies. In preferred embodiments, the anti-Clq antibodies promote clearance of Clq from circulation or tissues.

[0187] In some embodiments, the anti-C1q antibodies of the present disclosure inhibit the interaction between C1q and C1s. In some embodiments, the anti-C1q antibodies inhibit the interaction between C1q and C1r. In some embodiments, the anti-C1q antibodies inhibit the interaction between C1q and C1s and between C1q and C1r. In some embodiments, the anti-C1q antibodies inhibit the interaction between C1q and another antibody (e.g., an autoantibody). In preferred embodiments, the anti-C1q antibodies promote the clearance of C1q from the circulation or tissues. In some embodiments, the anti-C1q antibodies inhibit the respective interactions at a stoichiometry of less than 2.5:1, 2.0:1, 1.5:1, or 1.0:1. In some embodiments, the C1q antibodies inhibit interactions, such as C1q-C1s interactions, at approximately equimolar concentrations of C1q and anti-C1q antibodies. In other embodiments, the anti-C1q antibody is present in an amount of less than 20:1, less than 19.5:1; less than 19:1, less than 18.5:1, less than 18:1, less than 17.5:1, less than 17:1, less than 16.5:1, less than 16:1, less than 15.5:1, less than 15:1, less than 14.5:1, less than 14:1, less than 13.5:1, less than 13:1, less than 12.5:1, less than 12:1, less than 11.5:1, less than 1 In some embodiments, the anti-C1q antibody binds to C1q at a stoichiometry of 11:1, less than 10.5:1, less than 10:1, less than 9.5:1, less than 9:1, less than 8.5:1, less than 8:1, less than 7.5:1, less than 7:1, less than 6.5:1, less than 6:1, less than 5.5:1, less than 5:1, less than 4.5:1, less than 4:1, less than 3.5:1, less than 3:1, less than 2.5:1, less than 2.0:1, less than 1.5:1, or less than 1.0: 1. In some embodiments, the anti-C1q antibody binds to C1q at a stoichiometry of 20:1 to 1.0:1 or less than 1.0: 1. In some embodiments, the anti-C1q antibody binds to C1q at a stoichiometry of 6:1 to 1.0:1 or less than 1.0:1. In certain embodiments, the anti-C1q antibody binds to C1q with a binding stoichiometry of 2.5:1 to 1.0:1 or less than 1.0:1. In some embodiments, the anti-C1q antibody inhibits the interaction between C1q and C1r, or between C1q and C1s, or between C1q and both C1r and C1s. In some embodiments, the anti-C1q antibody inhibits the interaction between C1q and C1r, between C1q and C1s, and / or between C1q and both C1r and C1s. In some embodiments, the anti-C1q antibody binds to C1q A chain. In other embodiments, the anti-C1q antibody binds to C1q B chain. In other embodiments, the anti-C1q antibody binds to C1q C chain. In some embodiments, the anti-C1q antibody binds to C1q A chain, C1q B chain, and / or C1q C chain.In some embodiments, the anti-C1q antibody binds to the globular domain of the C1q A chain, B chain, and / or C chain. In other embodiments, the anti-C1q antibody binds to the collagen-like domain of the C1q A chain, C1q B chain, and / or C1q C chain.

[0188] When an antibody of the present disclosure inhibits an interaction between two or more complement factors, such as an interaction between C1q and C1s or an interaction between C1q and C1r, the interaction that occurs in the presence of the antibody can be reduced by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99% relative to a control in which the antibody of the present disclosure is not present. In certain embodiments, the interaction that occurs in the presence of the antibody is reduced by an amount ranging from at least 30% to at least 99% relative to a control in which the antibody of the present disclosure is not present.

[0189] In some embodiments, the antibodies of the present disclosure inhibit C2 or C4 cleavage by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99%, or an amount ranging from at least 30% to at least 99%, relative to a control in which the antibodies of the present disclosure are not present. Methods for measuring C2 or C4 cleavage are well known in the art. The EC values ​​of the antibodies of the present disclosure for C2 or C4 cleavage are as follows: 50 Values ​​may be less than 3 μg / ml; 2.5 μg / ml; 2.0 μg / ml; 1.5 μg / ml; 1.0 μg / ml; 0.5 μg / ml; 0.25 μg / ml; 0.1 μg / ml; 0.05 μg / ml. In some embodiments, antibodies of the present disclosure inhibit C2 or C4 cleavage at approximately equimolar concentrations of CIq and corresponding anti-CIq antibodies.

[0190] In some embodiments, the antibodies of the present disclosure inhibit autoantibody-dependent and complement-dependent cytotoxicity (CDC) by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99%, or an amount ranging from at least 30% to at least 99%, relative to a control in which the antibodies of the present disclosure are not present. 50 Values ​​can be less than 3 μg / ml; 2.5 μg / ml; 2.0 μg / ml; 1.5 μg / ml; 1.0 μg / ml; 0.5 μg / ml; 0.25 μg / ml; 0.1 μg / ml; 0.05 μg / ml.

[0191] In some embodiments, the antibodies of the present disclosure inhibit complement dependent cell-mediated cytotoxicity (CDCC) by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99%, or an amount ranging from at least 30% to at least 99%, relative to a control in which the antibodies of the present disclosure are not present. Methods for measuring CDCC are well known in the art. EC values ​​for CDCC inhibition by the antibodies of the present disclosure are as follows: 50 Values ​​may be less than 3 μg / ml; 2.5 μg / ml; 2.0 μg / ml; 1.5 μg / ml; 1.0 μg / ml; 0.5 μg / ml; 0.25 μg / ml; 0.1 μg / ml; 0.05 μg / ml. In some embodiments, the antibodies of the present disclosure inhibit CDCC but not antibody-dependent cellular cytotoxicity (ADCC).

[0192] Humanized anti-complement C1q antibody (incorporated by reference from U.S. Pat. No. 10,316,081)

[0193] The humanized antibodies disclosed herein specifically bind to complement factor C1q and / or C1q protein in the C1 complex of the classical complement pathway. Humanized anti-C1q antibodies may specifically bind to human C1q, human and mouse C1q, rat C1q, or human C1q, mouse C1q and rat C1q.

[0194] In some embodiments, the human heavy chain constant region is a human IgG4 heavy chain constant region, which comprises the amino acid sequence of SEQ ID NO: 47, or has at least 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90% homology with SEQ ID NO: 47. According to Kabat numbering, the human IgG4 heavy chain constant region may include an Fc region with one or more modifications and / or amino acid substitutions. In this case, the Fc region comprises an amino acid substitution of leucine to glutamic acid at position 248 (corresponding to the L115E mutation in IgG4), wherein this substitution inhibits the Fc region from interacting with an Fc receptor. In some embodiments, the Fc region comprises an amino acid substitution of serine to proline at position 241 (corresponding to the S108P mutation in IgG4), wherein this substitution prevents arm conversion in the antibody.

[0195] The amino acid sequence of the heavy chain constant domain of human IgG4 (S241P L248E; corresponding to S108P and L115E in SEQ ID NO: 47) is:

[0196] ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVESKYGPPCPPCPAPEFEGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVH NAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGK(SEQ ID NO:47).

[0197] The antibody may comprise a heavy chain variable domain and a light chain variable domain, wherein the heavy chain variable domain comprises an amino acid sequence selected from any one of SEQ ID NOs: 31-34, or an amino acid sequence having at least about 90% homology to an amino acid sequence selected from any one of SEQ ID NOs: 31-34. In certain such embodiments, the light chain variable domain comprises an amino acid sequence selected from any one of SEQ ID NOs: 35-38, or an amino acid sequence having at least about 90% homology to an amino acid sequence selected from any one of SEQ ID NOs: 35-38.

[0198] The amino acid sequence of heavy chain variable domain variant 1 (VH1) is:

[0199] The hypervariable region (HV R) of VH1 is in bold and underlined.

[0200] The amino acid sequence of heavy chain variable domain variant 2 (VH2) is:

[0201] The hypervariable region (H VR) of VH2 is in bold and underlined.

[0202] The amino acid sequence of heavy chain variable domain variant 3 (VH3) is:

[0203] The hypervariable region (H VR) of VH3 is in bold and underlined.

[0204] The amino acid sequence of heavy chain variable domain variant 4 (VH4) is:

[0205] The hypervariable region (H VR) of VH4 is in bold and underlined.

[0206] The amino acid sequence of kappa light chain variable domain variant 1 (Vκ1) is:

[0207] The hypervariable region (HVR) of Vκ1 is in bold and underlined.

[0208] The amino acid sequence of kappa light chain variable domain variant 2 (Vκ2) is:

[0209] The hypervariable region (HVR) of Vκ2 is in bold and underlined.

[0210] The amino acid sequence of kappa light chain variable domain variant 3 (Vκ3) is:

[0211] The hypervariable region (HVR) of Vκ3 is in bold and underlined.

[0212] The amino acid sequence of kappa light chain variable domain variant 4 (Vκ4) is:

[0213] The hypervariable region (HVR) of Vκ4 is in bold and underlined.

[0214] The antibody may comprise a light chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NOs: 35-38, while retaining HVR-L1 RASKSINKYLA (SEQ ID NO: 5), HVR-L2 SGSTLQS (SEQ ID NO: 6) and HVR-L3 QQHNEYPLT (SEQ ID NO: 7). The antibody may comprise a heavy chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NOs: 31-34, while retaining HVR-H1 GYHFTSYWMH (SEQ ID NO: 9), HVR-H2 VIHPNSGSINYNEKFES (SEQ ID NO: 10) and HVR-H3 ERDSTEVL PMDY (SEQ ID NO: 11).

[0215] In some embodiments, the antibody comprises a light chain variable domain amino acid sequence of SEQ ID NO: 35 and a heavy chain variable domain amino acid sequence of SEQ ID NO: 31. In some embodiments, the antibody comprises a light chain variable domain amino acid sequence of SEQ ID NO: 36 and a heavy chain variable domain amino acid sequence of SEQ ID NO: 32. In some embodiments, the antibody comprises a light chain variable domain amino acid sequence of SEQ ID NO: 37 and a heavy chain variable domain amino acid sequence of SEQ ID NO: 33. In some embodiments, the antibody comprises a light chain variable domain amino acid sequence of SEQ ID NO: 38 and a heavy chain variable domain amino acid sequence of SEQ ID NO: 34.

[0216] The full-length antibody Mab2 comprises heavy chain variable domain variant 3 (VH3) (SEQ ID NO: 33) and kappa light chain variable domain variant 3 (Vκ3) (SEQ Id NO: 37). Mab2-Fab is the Fab of the Mab2 antibody.

[0217] The antibody may comprise a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO: 14; and the light chain comprises the amino acid sequence of SEQ ID NO: 40.

[0218] The amino acid sequence of the heavy chain is:

[0219] The hypervariable region (HVR) of VH3 is in bold and underlined.

[0220] The amino acid sequence of the light chain is:

[0221]

[0222] The complementarity determining regions (CDRs) of SEQ ID NO: 40 are indicated in bold and underlined text.

[0223] In some embodiments, the humanized anti-C1q antibodies of the present disclosure include a heavy chain variable region containing a Fab region and a heavy chain constant region containing an Fc region, wherein the Fab region specifically binds to the C1q protein of the present disclosure, but the Fc region cannot bind to the C1q protein. In some embodiments, the Fc region is from a human IgG1, IgG2, IgG3 or IgG4 isotype. In some embodiments, the Fc region cannot induce complement activity and / or cannot induce antibody-dependent cellular cytotoxicity (ADCC). In some embodiments, the Fc region comprises one or more modifications, including but not limited to amino acid substitutions. In certain embodiments, the Fc region of the humanized anti-C1q antibodies of the present disclosure comprises an amino acid substitution at position 248 according to the Kabat numbering convention or a position corresponding to position 248 according to the Kabat numbering convention and / or at position 241 according to the Kabat numbering convention or a position corresponding to position 241 according to the Kabat numbering convention. In some embodiments, the amino acid substitution at position 248 or a position corresponding to position 248 inhibits the interaction of the Fc region with an Fc receptor. In some embodiments, the amino acid substitution at position 248 or a position corresponding to position 248 is an amino acid substitution of leucine to glutamic acid. In some embodiments, the amino acid substitution at position 241 or a position corresponding to position 241 prevents arm switching in the antibody. In some embodiments, the amino acid substitution at position 241 or a position corresponding to position 241 is an amino acid substitution of serine to proline. In certain embodiments, the Fc region of a humanized anti-C1q antibody of the present disclosure comprises the amino acid sequence of SEQ ID NO: 47, or an amino acid sequence having at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, or at least about 95% homology to the amino acid sequence of SEQ ID NO: 47.

[0224] Anti-C1q Fab fragment (e.g., FabA)

[0225] All anti-Clq antibody Fab fragment sequences are incorporated by reference from US Patent No. 10,723,788, the antibodies and related compositions disclosed in which are hereby incorporated by reference.

[0226] In certain embodiments, the present disclosure provides binding sites comprising a heavy chain (V H / C H 1) and light chain (V L / C L), wherein the anti-C1q antibody Fab fragment has six complementary determining regions (CDRs), V L and V H Three each (HCDR1, HCDR2, HCDR3 and LCDR1, LCDR2, LCDR3). The heavy chain of the antibody Fab fragment is truncated after the first heavy chain domain of IgG1 (SEQ ID NO: 39) and comprises the following amino acid sequence:

[0227]

[0228] The complementarity determining regions (CDRs) of SEQ ID NO: 39 are in bold and underlined.

[0229] The light chain domain of the antibody Fab fragment comprises the following amino acid sequence (SEQ ID NO: 40):

[0230]

[0231] The complementarity determining regions (CDRs) of SEQ ID NO: 40 are indicated in bold and underlined text.

[0232] FabA is an anti-C1q antibody Fab fragment comprising a heavy chain domain comprising SEQ ID NO:39 and a light chain domain comprising SEQ ID NO:40.

[0233] Mab1-Fab is the Fab of the Mab1 (M1) antibody.

[0234] Mab2-Fab is the Fab of the Mab2 antibody.

[0235] Mab3-Fab is the Fab of the Mab3 antibody.

[0236] Anti-C1q one-armed antibody

[0237] All anti-Clq one-armed antibody sequences are disclosed in US Patent Application No. 63 / 288,883 and US Patent Application No. 63 / 288,885, the antibodies and related compositions disclosed therein are hereby incorporated by reference.

[0238] In certain aspects, the present disclosure provides antibodies that bind to proteins in the complement cascade, such as C1q proteins. The antibody that binds to C1q comprises a single C1q antigen binding arm and an Fc region. The single C1q antigen binding arm may comprise a light chain variable domain and a heavy chain variable domain. The Fc region may comprise a complex of a first Fc polypeptide and a second Fc polypeptide. The Fc region may comprise an Fcγ receptor binding site mutation. The antibody may belong to the IgG4 category. In some embodiments, one but not both of the Fc polypeptides is an N-terminally truncated heavy chain. In some embodiments, the Fcγ receptor is FcγRI, FcγRII or FcγRIII, preferably FcγRI. The Fcγ receptor binding site mutation may comprise an IgG4 L115E mutation.

[0239]

[0240]

[0241] The complementarity determining regions (CDRs) of SEQ ID NO: 40 are marked in bold and underlined text. In some embodiments, HVR-L1 of the light chain variable domain has the sequence RASKSINKYLA (SEQ ID NO: 5), HVR-L2 of the light chain variable domain has the sequence SGSTLQS (SEQ ID NO: 6), and HVR-L3 of the light chain variable domain has the sequence QQHNEYPLT (SEQ ID NO: 7).

[0242] The light chain of the one-armed antibody may comprise the following light chain variable domain amino acid sequence:

[0243]

[0244] The one-armed antibody may comprise a light chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NO: 10, preferably while retaining HVR-L1 RASKSINKYLA (SEQ ID NO: 5), HVR-L2 SGSTLQS (SEQ ID NO: 6) and HVR-L3 QQHNEYPLT (SEQ ID NO: 7).

[0245] The one-armed antibody may comprise the following amino acid sequence of kappa light chain variable domain variant 1 (Vκ1):

[0246] The hypervariable region (HVR) of Vκ1 is in bold and underlined.

[0247] The one-armed antibody may comprise the following amino acid sequence of kappa light chain variable domain variant 2 (Vκ2):

[0248] The hypervariable region (HVR) of Vκ2 is in bold and underlined.

[0249] The one-armed antibody may comprise the following amino acid sequence of kappa light chain variable domain variant 3 (Vκ3):

[0250] The hypervariable region (HVR) of Vκ3 is in bold and underlined.

[0251] The one-armed antibody may comprise the following amino acid sequence of kappa light chain variable domain variant 4 (Vκ4):

[0252] The hypervariable region (HVR) of Vκ4 is in bold and underlined.

[0253] The one-armed antibody may comprise a light chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NOs: 11-14, while retaining HVR-L1 RASKSINKYLA (SEQ ID NO: 5), HVR-L2 SGSTLQS (SEQ ID NO: 6) and HVR-L3 QQHNEYPLT (SEQ ID NO: 7).

[0254] The antibody may belong to the IgG4 class. The sequence of the IgG4 heavy chain is

[0255]

[0256] The domains of IgG4 are as follows: CH1: 1-98, hinge: 99-110, CH2: 111-220 and CH3: 221-327. IgG4 may comprise mutations. For example, S108P mutation (for IgG4 arm exchange), L115E mutation (for FcR binding), T246W mutation (for knob-into-hole mutation), T246S mutation (for knob-into-hole mutation), L248A mutation (for knob-into-hole mutation), Y187V mutation (for knob-into-hole mutation), and / or N187A (deglycosylated for FcR binding), N187Q (deglycosylated for FcR binding) or N187G (deglycosylated for FcR binding).

[0257] One heavy chain of the one-armed antibody (heavy chain 1 domain) of the one-armed antibody may comprise the following amino acid sequence (SEQ ID NO: 2):

[0258]

[0259] The complementarity determining regions (CDRs) of SEQ ID NO:2 are indicated in bold and underlined text. The knob-in-hole T366W mutation (corresponding to the IgG4 T246W mutation) in SEQ ID NO:2 is indicated in underlined text. The S241P (for IgG4 arm switch, corresponding to S108P) and L248E (for FCR, corresponding to the L115E mutation) mutations are indicated in bold text. In some embodiments, the HVR-H1 of the heavy chain variable domain has the sequence GYHFTSYWMH (SEQ ID NO:9), the HVR-H2 of the heavy chain variable domain has the sequence VIHPNSGSINYNEKFES (SEQ ID NO:10), and the HVR-H3 of the heavy chain variable domain has the sequence ERDSTEVLPMDY (SEQ ID NO:11).

[0260] One heavy chain of the one-armed antibody (heavy chain 1 domain) of the one-armed antibody may comprise the following amino acid sequence (SEQ ID NO: 20):

[0261]

[0262] The complementarity determining regions (CDRs) of SEQ ID NO: 20 are marked in bold and underlined text. The knob-in-hole T366W mutation (corresponding to the IgG4 T246W mutation) in SEQ ID NO: 20 is marked in underlined text. The S241P (corresponding to S108P for IgG4 arm swap) mutation and L248 (corresponding to the L115E mutation) are marked in bold text.

[0263] The antibody may belong to the IgG1 class. The sequence of the IgG1 heavy chain is

[0264]

[0265] The domains of IgG1 are as follows: CH1: 1-98, hinge: 99-110, CH2: 111-223 and CH3: 224-330. IgG1 may include mutations. For example, L117A mutation (for FcR binding), L118A mutation (for FcR binding), T249W mutation (for knob-into-hole mutation), T249S mutation (for knob-into-hole mutation), L251A mutation (for knob-into-hole mutation) and / or Y290V mutation (for knob-into-hole mutation).

[0266] One heavy chain of the one-armed antibody (heavy chain 1 domain) of the one-armed antibody may comprise the following amino acid sequence (SEQ ID NO: 21):

[0267]

[0268] The complementarity determining regions (CDRs) of SEQ ID NO:21 are marked in bold and underlined text. The knob-in-hole T366W mutation (corresponding to the IgG1 T249W mutation) in SEQ ID NO:21 is marked in underlined text. The L234A (corresponding to the IgG1 L117A mutation) and L235A (corresponding to the IgG1 L1178 mutation) mutations are marked in bold text.

[0269] The heavy chain 1 of the one-armed antibody may comprise the following heavy chain variable domain amino acid sequence:

[0270]

[0271] The one-armed antibody may comprise a heavy chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NO: 15, preferably while retaining HVR-H1 GYHFTSYWMH (SEQ ID NO: 9), HVR-H2VIHPNSGSINYNEKFES (SEQ ID NO: 10) and HVR-H3ERDSTEVLPMDY (SEQ ID NO: 11).

[0272] The one-armed antibody may comprise the following amino acid sequence of heavy chain variable domain variant 1 (VH1):

[0273] The hypervariable region (HV R) of VH1 is in bold and underlined.

[0274] The one-armed antibody may comprise the following amino acid sequence of heavy chain variable domain variant 2 (VH2):

[0275] The hypervariable region (H VR) of VH2 is in bold and underlined.

[0276] The one-armed antibody may comprise the following amino acid sequence of heavy chain variable domain variant 3 (VH3):

[0277] The hypervariable region (H VR) of VH3 is in bold and underlined.

[0278] The one-armed antibody may comprise the following amino acid sequence of heavy chain variable domain variant 4 (VH4):

[0279] The hypervariable region (H VR) of VH4 is in bold and underlined.

[0280] The one-armed antibody may comprise a heavy chain variable domain amino acid sequence that is at least 85%, 90% or 95% identical to SEQ ID NOs: 16-19, while retaining HVR-H1 GYHFTSYWMH (SEQ ID NO: 9), HVR-H2 VIHPNSGSINYNEKFES (SEQ ID NO: 10) and HVR-H3 ERDSTEVLPMDY (SEQ ID NO: 11).

[0281] The second heavy chain of the one-armed antibody (heavy chain 2 domain) of the one-armed antibody is N-terminally truncated and may comprise the following amino acid sequence (SEQ ID NO: 3):

[0282]

[0283] There is no heavy chain variable domain and no CDRs in SEQ ID NO: 3. The knob-in-hole T366S / L368A / Y407V mutations in SEQ ID NO: 3 are marked with underlined text. The S241P and L248E mutations are marked with bold text.

[0284] The second heavy chain of the one-armed antibody (heavy chain 2 domain) of the one-armed antibody is N-terminally truncated and may comprise the following amino acid sequence (SEQ ID NO: 42):

[0285]

[0286] The second heavy chain of the one-armed antibody (heavy chain 2 domain) of the one-armed antibody is N-terminally truncated and may comprise the following amino acid sequence (SEQ ID NO: 43):

[0287]

[0288] The heavy chain variable domain and CDRs are absent in SEQ ID NO: 43. The knob-in-hole T366S / L368A / Y407V mutations in SEQ ID NO: 43 are indicated in underlined text. The L234A and L235A mutations are indicated in bold text.

[0289] The second heavy chain (heavy chain 2 domain) of the antibody may comprise any one of the following amino acid sequences (SEQ ID NOs: 44-49, 65):

[0290]

[0291]

[0292] The second heavy chain (heavy chain 2 domain) of the antibody may comprise any one of the following amino acid sequences (SEQ ID NOs: 48-51):

[0293]

[0294]

[0295] The CDRs in the second heavy chain variable domain were mutated to prevent binding to CIq in SEQ ID NOs:44-51. The CDR mutations are indicated in bold and underlined text. The knob-in-hole T366S / L368A / Y407V mutations in SEQ ID NOs:44-51 are indicated in underlined text.

[0296] In some embodiments, the antibody that binds to CIq comprises:

[0297] a light chain domain, the light chain domain comprising the amino acid sequence of SEQ ID NO: 40;

[0298] A first heavy chain domain, the first heavy chain domain comprising the amino acid sequence of SEQ ID NO: 2; and

[0299] The second heavy chain domain comprises the amino acid sequence of SEQ ID NO: 3; the second heavy chain domain is an N-terminally truncated heavy chain.

[0300] C1s inhibitors

[0301] The inhibitor of the classical complement pathway may be a C1s inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0302] Exemplary small molecule inhibitors of C1s are described in US Patent Application No. 17 / 379,334 and US Patent Application No. 18 / 097,811, the contents of which are incorporated herein by reference.

[0303] Anti-complement C1s antibody

[0304] Suitable inhibitors include antibodies that bind to complement C1s protein (i.e., anti-complement C1s antibodies, also referred to herein as anti-C1s antibodies and C1s antibodies) and nucleic acid molecules encoding such antibodies. Complement C1s is an attractive target because it is located upstream of the complement cascade and has a narrow range of substrate specificity. In addition, it is possible to obtain antibodies (such as, but not limited to, monoclonal antibodies) that specifically bind to the activated form of C1s.

[0305] All sequences mentioned in the following two paragraphs are incorporated by reference from US Patent Application No. 14 / 890,811, the antibodies and related compositions disclosed therein are incorporated herein by reference.

[0306] In certain aspects, methods of administering an anti-C1s antibody are disclosed herein. The antibody can be a murine antibody, a humanized antibody, or a chimeric antibody. In some embodiments, the light chain variable domain comprises HVR-L1, HVR-L2, and HVR-L3 of the murine anti-human C1s monoclonal antibody 5A1, and the heavy chain comprises HVR-H1, HVR-H2, and HVR-H3 of the murine anti-human C1s monoclonal antibody 5A1, produced by a hybridoma cell line deposited with ATCC on May 15, 2013, or a progeny thereof (ATCC Accession No. PTA-120351). In other embodiments, the light chain variable domain comprises HVR-L1, HVR-L2 and HVR-L3 of mouse anti-human C1s monoclonal antibody 5C12, and the heavy chain variable domain comprises HVR-H1, HVR-H2 and HVR-H3 of mouse anti-human C1s monoclonal antibody 5C12, which is produced by a hybridoma cell line deposited with ATCC on May 15, 2013, or a progeny thereof (ATCC Accession No. PTA-120352).

[0307] In some embodiments, the antibody specifically binds to C1s or C1s proenzyme and inhibits the biological activity of C1s or C1s proenzyme, such as the binding of C1s to C1q, the binding of C1s to C1r, or the binding of C1s to C2 or C4. The biological activity can be the proteolytic activity of C1s, the conversion of C1s proenzyme to an active protease, or the proteolytic cleavage of C2 or C4. In certain embodiments, the biological activity is the activation of the classical complement activation pathway, the activation of antibodies and complement dependent cytotoxicity, or C1F hemolysis.

[0308] All anti-C1s antibody sequences are incorporated by reference from US Patent No. 8,877,197, the antibodies and related compositions disclosed in which are hereby incorporated by reference.

[0309] In some embodiments, an anti-C1s antibody of the present disclosure (e.g., a subject antibody that specifically binds to an epitope in a complement C1s protein) comprises: a) a light chain region comprising a CDR selected from the group consisting of SEQ ID NO: 54, SEQ ID NO: 55, and SEQ ID NO: 56; and b) a heavy chain region comprising a CDR selected from the group consisting of SEQ ID NO: 57, SEQ ID NO: 58, and SEQ ID NO: 59. In some embodiments, the anti-C1s antibody comprises a humanized VH and / or VL framework region.

[0310] SEQ ID NO:54:SSVSSSYLHWYQ;

[0311] SEQ ID NO:55:STSNLASGVP;

[0312] SEQ ID NO:56:HQYYRLPPIT;

[0313] SEQ ID NO:57:GFTFSNYAMSWV;

[0314] SEQ ID NO:58:ISSGGSHTYY;

[0315] SEQ ID NO:59:ARLFTGYAMDY.

[0316] In some embodiments, an anti-C1s antibody of the present disclosure comprises a light chain variable region comprising the amino acid sequence of SEQ ID NO:21.

[0317] In some embodiments, an anti-C1s antibody of the present disclosure comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:22.

[0318] DIVMTQTTAIMSASLGERVTMTCTAS SSVSSSYLHWYQ QKPGSSPKLWIY STSNLASGVP ARFSGSGSGTFYSLTISSMEAEDDATYYC HQYYRLPPIT FGAGTKLELK (SEQ ID NO:60)

[0319] QVKLEESGGALVKPGGSLKLSCAAS GFTFSNYAMSWV RQIPEKRLEWVAT ISSGGSHTYY LDSVKGRFTISRDNARDTLYLQMSSLRSEDTALYYC ARLFTGYAMDY WGQGTSVT (SEQ ID NO: 22)

[0320] In some embodiments, an anti-C1s antibody of the present disclosure comprises a light chain variable region comprising the amino acid sequence of SEQ ID NO:23.

[0321] In some embodiments, an anti-C1s antibody of the present disclosure comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:24.

[0322] QIVLTQSPATLSLSPGERATMSCTAS SSVSSSYLHWYQ QKPGKAPKLWIY STSNLASGVP SRFSGSGSGTDYTLTISSLQPEDFATYYC HQYYRLPPIT FGQGTKLEIK (SEQ ID NO: 23)

[0323] EVQLVESGGGLVKPGGSLRLSCAAS GFTFSNYAMSWV RQAPGKGLEWVAT ISSGGSHTYY LDSVKGRFTISRDNSKNTLYLQMNSLRAEDTALYYC ARLFTGYAMDY WGQGTLVTVSS (SEQ ID NO: 24)

[0324] In some embodiments, an anti-C1s antibody of the present disclosure comprises a light chain comprising the amino acid sequence of SEQ ID NO:25.

[0325] In some embodiments, an anti-C1s antibody of the present disclosure comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:26.

[0326] The sultilimab antibody comprises a light chain comprising the amino acid sequence of SEQ ID NO:25 and a heavy chain comprising the amino acid sequence of SEQ ID NO:26.

[0327] QIVLTQSPATLSLSPGERATMSCTAS SSVSSSYLHWYQ QKPGKAPKLWIY STSNLASGVP SRFSGSGSGTDYTLTISSLQPEDFATYYC HQYYRLPPIT FGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQID NO:25)

[0328] EVQLVESGGGLVKPGGSLRLSCAAS GFTFSNYAMSWV RQAPGKGLEWVAT ISSGGSHTYY LDSVKGRFTISRDNSKNTLYLQMNSLRAEDTALYYC ARLFTGYAMDY WGQGTLVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTK TYTCNVDHKPSNTKVDKRVESKYGPPCPPCPAPEFEGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSN KGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGK(SEQ ID NO:26)

[0329] In some embodiments, an anti-C1s antibody of the present disclosure comprises: a) a light chain region comprising a CDR selected from the group consisting of SEQ ID NO: 27, SEQ ID NO: 28, and SEQ ID NO: 56; and b) a heavy chain region comprising a CDR selected from the group consisting of SEQ ID NO: 29, SEQ ID NO: 30, and SEQ ID NO: 61. In some embodiments, an anti-C1s antibody comprises a humanized VH and / or VL framework region.

[0330] SEQ ID NO:27: TASSSVSSSYLH;

[0331] SEQ ID NO:28:STSNLAS;

[0332] SEQ ID NO:56:HQYYRLPPIT;

[0333] SEQ ID NO:29:NYAMS;

[0334] SEQ ID NO:30:TISSGGSHTYYLDSVKG;

[0335] SEQ ID NO:61:LFTGYAMDY.

[0336] In some embodiments, an anti-C1s antibody of the present disclosure comprises a light chain variable region comprising the amino acid sequence of SEQ ID NO:32.

[0337] In some embodiments, an anti-C1s antibody of the present disclosure comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO:33.

[0338] QIVLTQSPAIMSASLGERVTMTCTASSSVSSSYLHWYQQKPGSSPKLWIYSTSNLASGVPARFSGSGSGTFYSLTISSMEAEDDATYYCHQYYRLPPITFGAGTKLELK(SEQ ID NO:62)

[0339] EVMLVESGGALVKPGGSLKLSCAASGFTFSNYAMSWVRQIPEKRLEWVATISSGGSHTYYLDSVKGRFTISRDNARDTLYLQMSSLRSEDTALYYCARLFTGYAMDYWGQGTSVTVSS(SEQ ID NO:63)

[0340] The anti-C1s antibody may be selected from an antigen-binding fragment, an Ig monomer, a Fab fragment, a F(ab')2 fragment, a Fd fragment, a scFv, a scAb, a dAb, a Fv, a single domain heavy chain antibody, a single domain light chain antibody, a monospecific antibody, a bispecific antibody or a multispecific antibody.

[0341] Disclosed herein are methods of administering an antibody that competes for binding to an epitope bound by antibody IPN003 (also referred to herein as "IPN-M34" or "M34" or "TNT003"), e.g., an antibody comprising a variable domain of antibody IPN003, e.g., antibody IPN003.

[0342] All anti-C1s antibody sequences are incorporated by reference from US Patent Application No. 17 / 749,362, the antibodies and related compositions disclosed in which are hereby incorporated by reference.

[0343] In some embodiments, an anti-C1s antibody of the present disclosure comprises (1) a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, and (2) a light chain variable region comprising LCDR1, LCDR2, and LCDR3, wherein:

[0344] (a) HCDR1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 66, 72, 78, 84, 89, 94, 99, 103 and 107,

[0345] (b) HCDR2 comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 67, 73, 79, 85, 90, 95, 100, 104 or 108,

[0346] (c) HCDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 68, 74, 80, 101, 105 or 109,

[0347] (d) LCDR1 comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 69, 75, 81, 86, 91, 96, 102, 106 or 110,

[0348] (e) LCDR2 comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 70, 76, 82, 87, 92 or 97, and

[0349] (f) LCDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 71, 77, 83, 88, 93 or 98. Table 2: Kabat CDRs

[0350]

[0351] C1r inhibitors

[0352] The inhibitor of the classical complement pathway may be a C1r inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0353] The anti-C1r antibodies disclosed herein are potent inhibitors of C1r.

[0354] The anti-C1r antibodies disclosed herein inhibit the interaction between C1r and C1q or between C1r and C1s, or wherein the anti-C1r antibodies inhibit the catalytic activity of C1r, or inhibit the processing of pro-C1r to an active protease.

[0355] C1 complex inhibitors

[0356] The inhibitor of the classical complement pathway may be a C1 complex inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0357] The anti-C1 complex antibodies disclosed herein are potent inhibitors of the C1 complex.

[0358] The anti-C1 complex antibodies disclosed herein inhibit activation of C1r or C1s or block their ability to act on C2 or C4. The anti-C1 complex antibodies disclosed herein bind to a combinatorial epitope within the C1 complex, wherein the combinatorial epitope comprises amino acids of both C1q and C1s; amino acids of both C1q and C1r; amino acids of both C1r and C1s; or amino acids of each of C1q, C1r, and C1s.

[0359] C2 inhibitors

[0360] The inhibitor of the classical complement pathway may be a C2 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0361] The anti-C2 inhibitors disclosed herein are potent inhibitors of C2. In some embodiments, the C2 inhibitor is ARGX-117 (ArgenX) described in US Pat. No. 11,161,900, the contents of which are incorporated herein by reference.

[0362] All anti-C2 antibody sequences are incorporated by reference from US Patent No. 11,161,900, the antibodies and related compositions disclosed in which are hereby incorporated by reference.

[0363] In some embodiments, an anti-C2 antibody of the present disclosure comprises (1) a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, and (2) a light chain variable region comprising LCDR1, LCDR2, and LCDR3, wherein: HCDR1 comprises the amino acid sequence of SEQ ID NO: 111 (DYNMD), HCDR2 comprises the amino acid sequence of SEQ ID NO: 112 (DINPNYESTGYNQKFKG), HCDR3 comprises the amino acid sequence of SEQ ID NO: 113 (EDDHDAFAY), LCDR1 comprises the amino acid sequence of SEQ ID NO: 114 (RASKSVRTSGYNYMH), LCDR2 comprises the amino acid sequence of SEQ ID NO: 115 (LASNLKS), LCDR3 comprises the amino acid sequence of SEQ ID NO: 116 (QHSRELPYT),

[0364] In some embodiments, an anti-C2 antibody of the present disclosure comprises a VH domain comprising the amino acid sequence shown in SEQ ID NO:118; and a VL domain comprising the amino acid sequence shown in SEQ ID NO:117.

[0365] DNVLTQSPDSLAVSLGERATISCRASKSVRTSGYNYMHWYQQKPGQPPKLLIYLASNLKSGVPDRFSGSGSGTDFTLTISSLQAEDAATYYCQHSRELPYTFGQGTKLEIK(SEQ ID NO:117)

[0366] EVQLVQSGAEVKKPGASVKVSCKASGYTFTDYNMDWVRQATGQGLEWIGDINPNYESTGYNQKFKGRATMTVDKSISTAYMELSSLRSEDTAVYYCAREDDHDAFAYWGQGTLVTVSS (SEQ ID NO: 118).

[0367] C3 inhibitors

[0368] The inhibitor of the classical complement pathway may be a C3 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0369] The anti-C3 inhibitors disclosed herein are potent inhibitors of C3. In some embodiments, the C3 inhibitor is APL-9 (Apellis) and / or AMY-101 (Amyndas) and / or IVT CB 2782-PEG (Catalyst Biosciences and Biogen).

[0370] C4 inhibitors

[0371] The inhibitor of the classical complement pathway may be a C4 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0372] The anti-C4 inhibitors disclosed herein are potent inhibitors of C4.

[0373] Complement inhibition

[0374] Many molecules that inhibit complement activity are known. In addition to known compounds, suitable inhibitors can be screened by the methods described herein. As described above, normal cells can produce proteins that block complement activity, such as CD59, C1 inhibitors, etc. In some embodiments of the present disclosure, complement is inhibited by upregulating the expression of genes encoding such polypeptides.

[0375] Molecular modifications that block complement activation are also known in the art. For example, such molecules include, but are not limited to, modified complement receptors, such as soluble CR1. The mature protein of the most common CR1 allotype contains 1998 amino acid residues: an extracellular domain of 1930 residues, a transmembrane region of 25 residues, and a cytoplasmic domain of 43 residues. The entire extracellular domain consists of 30 repeating units, called short common repeats (sCR) or complement control protein repeats (CCPR), each repeating unit consisting of 60 to 70 amino acid residues. Recent data indicate that C1q specifically binds to human CR1. Therefore, CR1 recognizes all three complement opsonins, namely C3b, C4b and C1q. Soluble forms of recombinant human CR1 (sCR1) lacking transmembrane and cytoplasmic domains have been produced and shown to retain all known functions of native CR1. The cardioprotective effect of sCR1 in animal models of ischemia / reperfusion injury has been confirmed. Several types of human C1q receptors (C1qR) have been described. These include a widely distributed 60 to 67-kDa receptor, termed cC1qR, because it binds the collagen-like domain of C1q. This C1qR variant was shown to be calreticulin; a 126-kDa receptor that regulates monocyte phagocytosis. gC1qR is not a membrane-bound molecule but a secreted soluble protein that has affinity for the globular region of C1q and may serve as a fluid-phase regulator of complement activation.

[0376] Decay accelerating factor (DAF) (CD55) consists of four SCRs plus a serine / threonine-rich domain that is capable of extensive O-linked glycosylation. DAF is attached to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor and, through its ability to bind C4b and C3b, exerts its effects by dissociating C3 and C5 convertases. Soluble DAF (sDAF) has been shown to inhibit complement activation.

[0377] C1 inhibitor, a member of the serpin family of serine protease inhibitors, is a heavily glycosylated plasma protein that prevents fluid-phase C1 activation. C1 inhibitor modulates the classical pathway of complement activation by blocking the active sites of C1r and C1s and dissociating them from C1q.

[0378] Peptide inhibitors of complement activation include C5a, and other inhibitory molecules include fucoidan.

[0379] Treatment

[0380] The present disclosure is generally directed to methods of treating lupus nephritis in a subject in need thereof. The method comprises determining that the subject has at least one of the following characteristics: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. C4x can be selected from C4a and C4d. The method also includes administering to the subject an inhibitor of the classical complement pathway, e.g., if the subject has elevated C4x levels; elevated C4x / C4 ratios; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratios; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratios; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. In some embodiments, the subject has at least two of the characteristics. For example, the characteristics can be selected from elevated C4x levels, elevated C4x / C4 ratios, and decreased C4 levels, and / or the characteristics can be selected from the group consisting of elevated C1sC1 inhibitor levels, elevated C1sC1 inhibitor / C1s ratios, and decreased C1s levels. In some embodiments, the subject also has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3). In some embodiments, the subject has at least one of the following additional characteristics: elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the subject has elevated UPCR as another additional characteristic. A therapeutically effective amount of an inhibitor may be administered.

[0381] We observed evidence of complement activation in patients with lupus nephritis relative to healthy controls. Specifically, the levels of C4a, C4d, C1sC1 inhibitor, PACA1, and PACA3, as well as the ratios of C4a / C4, C4d / C4, C1sC1 inhibitor / C1s, C2b / C2, and C3a / C3 were significantly increased in patients with lupus nephritis, whereas the levels of C4, C1s, C2, and C3 were decreased in patients with lupus nephritis. More specifically, we observed that the levels of C4d and the C4d / C4 ratio were significantly increased in patients with lupus nephritis in the setting of fever, whereas the levels of C1q, C1s, C2, and C4 were decreased, consistent with activation of the classical complement pathway (increased activation and component consumption).

[0382] The data from Example 1 indicate that patients identified by using a model assessing elevated C4d levels and / or elevated C4d / C4 ratios exhibit potential clinical improvement with anti-C1q antibody therapy. In addition, these data indicate that a subset of LN patients exhibiting elevated levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, C4a / C4, C1sC1 inhibitor / C1s, and C2b / C2, or reduced levels of C4, C1s, C2 may also benefit from therapy with classical complement inhibitors, or more specifically, anti-C1q antibody therapy. Treatment with anti-C1q antibodies (such as full-length anti-C1q antibodies or Fab fragments thereof) produces clinical benefit in lupus nephritis patients as determined by using a model assessing complement levels and / or PACA levels alone or in combination with UPCR, as shown in Example 4. It is demonstrated that complement levels (e.g., C4a, C4d, C4, C2b, C2, C1sC1 inhibitor, C1s, C3a, C3a, C3, PACA1, PACA3 and C4a / C4, C4d / C4, C1sC1 inhibitor / C1s, C2b / C2, and C3a / C3 ratios) and / or PACA levels, alone or in combination with UPCR, and the use of classical complement inhibitors, more specifically, anti-C1q antibodies, including anti-C1q antibody fragments (e.g., Fab), reliably produce clinical benefit in patients with lupus nephritis.

[0383] Systemic lupus erythematosus (SLE) is a biologically and clinically heterogeneous autoimmune disease characterized by a wide variety of clinical involvement, particularly renal involvement. Renal involvement in SLE is called LN. Up to 50% to 60% of SLE patients develop LN within the first 10 years of disease, and it is the leading cause of morbidity and mortality in SLE.

[0384] According to the International Society of Nephrology / Renal Pathology Society (ISN / RPS) clinical pathology classification system, grade III (focal hyperplasia) and grade IV (diffuse hyperplasia) LN are considered to be more serious than grade I (minor disease) or grade II (mesangial proliferative) disease, with a poorer prognosis, and need to be treated with effective immunosuppressants such as cyclophosphamide, mycophenolate mofetil (MMF) and high-dose glucocorticoids. Grade III and grade IV LN can all have active (proliferative), inactive (sclerotic) or combined active and inactive lesions. In addition, grade V (membranous) glomerulonephritis can occur independently or coexist with grade III and grade IV LN.

[0385] There remains a substantial unmet need for safe and effective new treatment options in LN, with the goal of providing rapid and durable clinical benefit. Although guidelines for the treatment of LN have been established worldwide, it is currently unclear which therapy is best for individual patients. Therefore, a precision medicine approach is necessary to identify patients who may respond better to certain therapies and avoid exposure to potentially harmful agents that are unlikely to provide benefit.

[0386] It is estimated that approximately 5 million people worldwide have some form of lupus, and approximately half of all SLE patients are affected by LN during their lifetime. LN, particularly grade III / IV proliferative glomerulonephritis, is a serious and life-threatening disease associated with a 6-fold increased mortality rate compared with the general population. In addition, lupus patients who develop ESRD have a 26-fold increased risk of death, more than twice the risk associated with malignancy or cardiovascular disease. The increased risk of death in LN is >2-fold compared with extrarenal SLE.

[0387] Grade III / IV LN is typically treated with immunosuppressants such as cyclophosphamide, MMF, azathioprine, and glucocorticoids, and calcineurin inhibitors and rituximab can be used for refractory cases. All of these agents have potentially severe toxicities, and while 50% to 80% of patients receiving these standard therapies may experience a renal response at 1 year, most of these responses are only in partial remission. In addition, up to 30% of LN patients will progress to ESRD despite standard treatment. Two advanced therapies, belimumab and cyclosporine, have recently been approved for grade III / IV LN as an addition to standard treatment, but in key trials, only about 30% to 40% of patients achieved complete renal responses with long-term administration of these agents. There remains a significant unmet need for the development of safe and effective LN therapies for these patients.

[0388] Autoantibodies against various autoantigens (such as double-stranded DNA, RNA and nucleosomes) are believed to contribute to the pathogenesis of lupus. In addition, autoantibodies targeting the collagen-like stalk domain of C1q are highly enriched in LN patients and may amplify complement-mediated inflammation in LN and are associated with disease onset. Autoantibodies bind to their cognate antigens to form immune complexes deposited in the vascular walls, glomeruli and renal interstitium of LN. Immune complexes trigger the activation of the classical complement cascade, with C1q acting as the closest step in this pathway. Through a series of recruitment steps and enzymatic reactions, C1q and its downstream components such as C4, C3 and their activation products are deposited in the renal tissue of most LN patients. These signal transduction events lead to the activation of antigen presenting cells, the release of inflammatory mediators and the recruitment of additional innate and adaptive immune cells, resulting in the destruction of the structure and function of the glomerular basement membrane (GBM), the occurrence of proteinuria and subsequent tissue damage. Pathogenic anti-C1q autoantibodies (PACA) may further amplify classical complement pathway-mediated inflammation by binding to C1q associated with immune complexes present in renal tissue, thereby triggering even more complement activation ( Figure 2 Importantly, while PACA binds to the tail region of substrate-bound C1q, FabA recognizes the head region of C1q and prevents C1q from binding to its substrate in the first place. Thus, FabA not only inhibits the proximal step of classical complement pathway activation, but also disrupts PACA-mediated classical pathway amplification.

[0389] Complement factor C4 and its activation product C4d are important biomarkers of LN. Reduced levels of C4 and increased amounts of C4d in the circulation indicate activation of the classical complement pathway and are associated with active LN. The level of C4d in plasma is closely related to C4d deposition in renal tissue from patients with active LN. Compared with SLE patients without LN, patients with autoimmune kidney disease IgA nephropathy, and healthy controls, the C4d / C4 ratio of active LN is increased. In addition, the C4d / C4 ratio predicts the presence of active LN more accurately than other biomarkers (e.g., C3, C4, and C4d). Therefore, C4d / C4 can identify active LN patients who are most likely to respond to therapies targeting the classical complement cascade. Similarly, as shown herein, LN patients have elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels.

[0390] Example 1 shows that the C4d / C4 ratio also correlates with the levels of autoantibodies to C1q isoforms 1 and 3, which are known to activate the classical pathway. These data suggest that a subset of LN patients who exhibit high C4d / C4 ratios and specific markers of classical pathway activation may benefit from classical complement inhibitors, or more specifically, anti-C1q therapy. In addition, these data suggest that a subset of LN patients who exhibit high levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, C4a / C4, gC1sC1 inhibitor / C1s and C2b / C2 or reduced levels of C4, C1s, C2 may benefit from therapy with classical complement inhibitors, or more specifically, anti-C1q therapy.

[0391] Furthermore, high circulating levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, and the C2b / C2 ratio, C1sC1 inhibitor / C1s ratio, and C3a / C3 ratio, as well as decreased levels of C4, C2, C1s, and C3 in patients with active LN suggest that complement may drive disease progression and severity. Fig.21A -O).

[0392] The high correlation between complement factors in LN patients suggests coordinated pathway activity ( Figure 6 and Fig. 22 No association was observed in the healthy control group ( Figure 7 ). The data showed a strong association between a high C4d / C4 ratio and the presence of PACA. The data also showed strong associations between other complement factors in LN patients, for example, C4d / C4 and C4d had a strong positive correlation, and C2b and C2b / C2 had a strong inverse correlation ( Fig. 22 ). This correlation is used to select patients most likely to respond to therapy with the classical complement pathway, more specifically anti-C1q therapy.

[0393] According to standard of care, C4d / C4 is reduced after a febrile event, but the effect is not sustained ( Fig. 9 ). Fig.10 Changes in urine protein / creatinine ratio (UPCR) and C4 in response to standard of care treatment are shown. Increases in C4 levels are approximately equivalent to decreases in C4d / C4 (C4d is new and not routinely monitored). Increases in C4 levels are consistent with improvements in UPCR. Decreases in C4 levels after a febrile episode suggest residual inflammation that may lead to recurrence of fever. Data also suggest that clinical C4 measurements track UPCR trajectories ( Fig.11 Increased C4 and decreased C4d / C4 were associated with improved disease activity ( Fig.12 ). Low C4 and high C4d / C4 were also associated with disease activity.

[0394] The presence of C4d in renal biopsies indicates the involvement of classical complement and the unique specificity of C4d as a biomarker. Fig.15 ). In addition, the high accuracy of this biomarker identified SLE patients with LN ( Fig.16 The high sensitivity and specificity of C4d / C4 as a diagnostic biomarker compared with other diagnostic biomarkers (such as proteinuria, anti-DNA antibodies) suggest a potential causal role of classical complement in LN.

[0395] Plasma C4d can inform the C4d level in kidney tissue.

[0396] In summary, these data provide a strong scientific and clinical rationale for evaluating anti-C1q therapy in patients with grade III / IV LN with evidence of classical complement pathway activation.

[0397] Patients with active LN with a high C4d / C4 ratio may have higher PACA1( Figure 8A-B ). PACA1 may be an additional factor that amplifies disease severity. The improvement in the C4d / C4 ratio after treatment further supports the relevance of the complement pathway in disease pathology ( Fig. 9 and Fig.10 ).

[0398] PACA1 (pathogenic anti-C1q antibody) levels remain elevated throughout treatment. Patients with active LN who have a high C4d / C4 ratio may have higher PACA1 ( Figure 8A-B ). PACA1 may be an additional factor for amplifying disease severity. PACA (pathogenic anti-C1q antibody) levels are associated with classical complement activation in patients with lupus nephritis. Improvement in the C4d / C4 ratio after treatment further supports the relevance of the complement pathway in disease pathology.

[0399] PACA is different from therapeutic anti-C1q antibodies, such as Mab2 and other therapeutic antibodies and antibody fragments designed to inhibit C1q function. Mab2 and other therapeutic antibodies and antibody fragments recognize the substrate binding head group of C1q and prevent C1q substrate binding / activation. In contrast, PACA recognizes the collagen tail of C1q when it is bound to a substrate and recruits additional C1q through its Fc region - thereby enhancing C1q activity.

[0400] Described herein is the finding that PACA plasma titers correlate with the extent of renal damage in patients with lupus nephritis, as assessed by the urine protein / creatinine ratio (UPCR) as a measure of proteinuria. In Example 3 below, PACA of the IgG1 (i.e., PACA1) and IgG3 isotypes (i.e., PACA3) provided the strongest correlation with UPCR, while no significant correlation was observed with levels of IgG2 and IgG4 antibodies to C1q ( Fig.13 ). These results are important because IgG1 and IgG3 are the antibody isotypes that most strongly recruit additional C1q (complement fixation isotypes), whereas IgG2 and IgG4 recruit little or no C1q to immune complexes and are therefore not associated with increased levels of disease. Although IgM antibodies strongly activate C1q, they are characteristic of acute disease and would not be expected to circulate at appreciable levels in chronic conditions such as lupus nephritis. PACA1 and PACA3 levels also correlate with C4d and the C4d / C4 ratio ( Fig.14 ).

[0401] In addition, early studies in animal models of lupus nephritis reported a causal relationship between anti-C1q antibodies and renal damage. Administration of PACA significantly exacerbated the disease, with a large increase in complement deposition in the glomerular subendothelial space ( Fig.17 and Fig.18 PACA is also characterized by its ability to selectively bind substrate-bound C1q and activate the classical complement pathway. The binding of PACA to substrate-bound C1q is not affected by soluble C1q ( Fig.19 ). Thus, PACA correlates with disease severity and is a complement activator of the IgG1 and IgG3 isotypes, whereas IgG4 does not fix C1q. Anti-C1q IgG1 and IgG3, but not IgG4 levels, correlate with serum C4d / C4 ratios ( Fig. 20 ). This is consistent with the complement activation capacity of the antibody isotype.

[0402] The present disclosure is generally directed to methods of treating lupus nephritis in a subject in need thereof. The method comprises determining that the subject has at least one of the following characteristics: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. C4x can be C4a or C4d. The method also includes administering to the subject an inhibitor of the classical complement pathway, e.g., if the subject has elevated C4x levels; elevated C4x / C4 ratios; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratios; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratios; decreased C2 levels; or elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels. In some embodiments, the subject has at least two of the characteristics. For example, the characteristics can be selected from elevated C4x levels, elevated C4x / C4 ratios, and decreased C4 levels, and / or the characteristics can be selected from the group consisting of elevated C1sC1 inhibitor levels, elevated C1sC1 inhibitor / C1s ratios, and decreased C1s levels. In some embodiments, the subject also has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3). In some embodiments, the subject has at least one of the following additional characteristics: elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the subject has elevated UPCR as another additional characteristic. A therapeutically effective amount of an inhibitor may be administered.

[0403] In some embodiments, the subject has an elevated C4x level. In some embodiments, the subject also has at least one of the following additional features: elevated C4x / C4 ratio; decreased C4 level; elevated C1sC1 inhibitor level; elevated C1sC1 inhibitor / C1s ratio; decreased C1s level; elevated C2b level; elevated C2b / C2 ratio; decreased C2 level; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a level; elevated C3a / C3 ratio; or decreased C3 level. In some embodiments, the elevated C4x level is greater than the C4x level of a normal or healthy subject, greater than the C4x level of a normal or healthy subject of similar age, or greater than a reference C4x level. The reference C4x level may be a value equal to or greater than the mean or median of C4x levels in samples from subjects with lupus nephritis, or a value equal to or greater than the mean or median of C4x levels in samples from subjects with lupus nephritis of similar age. The reference C4x level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 70th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 75th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 80th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 85th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 90th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 95th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level may be a value equal to or greater than the 100th percentile of C4x levels in samples from subjects with lupus nephritis. The reference C4x level can be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples from age-matched lupus nephritis subjects.The reference C4x level may be a value equal to or greater than the 70th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 75th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 80th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 85th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 90th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 95th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 100th percentile of C4x levels in samples from lupus nephritis subjects of similar age. The reference C4x level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C4x levels in samples from normal or healthy subjects. The reference C4x level may be a value equal to or greater than the 70th percentile of C4x levels in samples from normal or healthy subjects. The reference C4x level may be a value equal to or greater than the 75th percentile of C4x levels in samples from normal or healthy subjects. The reference C4x level may be a value equal to or greater than the 80th percentile of C4x levels in samples from normal or healthy subjects. The reference C4x level may be a value equal to or greater than the 85th percentile of the C4x level in a sample derived from a normal or healthy subject. The reference C4x level may be a value equal to or greater than the 90th percentile of the C4x level in a sample derived from a normal or healthy subject. The reference C4x level may be a value equal to or greater than the 95th percentile of the C4x level in a sample derived from a normal or healthy subject. The reference C4x level may be a value equal to or greater than the 100th percentile of the C4x level in a sample derived from a normal or healthy subject. The reference C4x level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of the C4x level in a sample derived from a normal or healthy subject of similar age.The reference C4x level may be a value equal to or greater than the 70th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 75th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 80th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 85th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 90th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 95th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. The reference C4x level may be a value equal to or greater than the 100th percentile of C4x levels in samples derived from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C4x level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% higher than the reference C4x level. or 500%, or the elevated C4x level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C4x level.

[0404] In some embodiments, the subject has an elevated C4x / C4 ratio. In some embodiments, the subject also has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C4x / C4 ratio is greater than the C4x / C4 ratio of a normal or healthy subject, greater than the C4x / C4 ratio of a normal or healthy subject of comparable age, or greater than a reference C4x / C4 ratio. The reference C4x / C4 ratio may be a value equal to or greater than the mean or median of the C4x / C4 ratio in samples from subjects with lupus nephritis, or may be equal to or greater than the mean or median of the C4x / C4 ratio in samples from subjects with lupus nephritis of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C4x / C4 ratio in samples from subjects with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 70th percentile of the C4x / C4 ratio in samples from subjects with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 75th percentile of the C4x / C4 ratio in a sample derived from a subject with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 80th percentile of the C4x level in a sample derived from a subject with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 85th percentile of the C4x / C4 ratio in a sample derived from a subject with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 90th percentile of the C4x / C4 ratio in a sample derived from a subject with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 95th percentile of the C4x / C4 ratio in a sample derived from a subject with lupus nephritis. The reference C4x / C4 ratio may be a value equal to or greater than the 100th percentile of the C4x / C4 ratio in a sample derived from a subject with lupus nephritis.The reference C4x / C4 ratio may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C4x / C4 ratio in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 70th percentile of the C4x / C4 ratio in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 75th percentile of the C4x / C4 ratio in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 80th percentile of the C4x / C4 ratio in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 85th percentile of C4x / C4 ratios in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 90th percentile of C4x / C4 ratios in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 95th percentile of C4x / C4 ratios in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 100th percentile of C4x / C4 ratios in samples from lupus nephritis subjects of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 70th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 75th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 80th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 85th percentile of the C4x / C4 ratio in a sample from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 90th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject.The reference C4x / C4 ratio may be a value equal to or greater than the 95th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject. The reference C4x / C4 ratio may be a value equal to or greater than the 100th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of lupus. The reference C4x / C4 ratio may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 70th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 75th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 80th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 85th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 90th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 95th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject of similar age. The reference C4x / C4 ratio may be a value equal to or greater than the 100th percentile of the C4x / C4 ratio in a sample derived from a lupus normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C4x / C4 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, 4500%, 5000%, 6500%, 7000%, 75000%, 80000%, 85000%, 90000%, 95000%, 1000000%, 200000%, 3000000% %, 400% or 500% higher than the reference C4x / C4 ratio, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference C4x / C4 ratio.

[0405] In some embodiments, the subject has a reduced C4 level. In some embodiments, the subject also has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; reduced C1s levels; elevated C2b levels; elevated C2b / C2 ratio; reduced C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or reduced C3 levels. In some embodiments, the reduced C4 level is less than the C4 level of a normal or healthy subject. The reduced C4 level may be less than the C4 level of a normal or healthy subject of similar age, may be less than a reference C4 level, or may be a value equal to or less than the mean or median of the C4 levels in a sample derived from a subject with lupus nephritis. In some embodiments, the reference C4 level is a value equal to or less than the mean or median of C4 levels in samples from age-matched lupus nephritis subjects. The reference C4 level can be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in samples from lupus nephritis subjects. The reference C4 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile of C4 levels in samples from age-matched lupus nephritis subjects. The reference C4 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile of C4 levels in samples from normal or healthy subjects. The reference C4 level can be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the decreased C4 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3 ... %-200%, 200%-300%, 300%-400%, 400%-500% below the reference C4 level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% below the reference C4 level.

[0406] In some embodiments, the subject has an elevated C1sC1 inhibitor level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C1sC1 inhibitor level is greater than the C1sC1 inhibitor level of a normal or healthy subject, greater than the C1sC1 inhibitor level of a normal or healthy subject of similar age, or greater than a reference C1sC1 inhibitor level. The reference C1sC1 inhibitor level may be a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples from subjects with lupus nephritis, or may be a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples from subjects with lupus nephritis of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C1sC1 inhibitor levels in samples from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 70th percentile of C1sC1 inhibitor levels in samples from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 75th percentile of C1sC1 inhibitor levels in samples from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor level may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis.The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 70th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 75th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor levels in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 70th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 75th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects.The reference C1sC1 inhibitor level may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects. The reference C1sC1 inhibitor level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 70th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 75th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor levels in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor level may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor levels in age-matched normal or healthy samples. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis.In some embodiments, the elevated C1sC1 inhibitor level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3 ... 0%, 400% or 500% above the reference C1sC1 inhibitor level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% above the reference C1sC1 inhibitor level.

[0407] In some embodiments, the subject has an elevated C1sC1 inhibitor / C1s ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C4x / C4 ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject of comparable age. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is greater than a reference C1sC1 inhibitor / C1s ratio. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 70th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 75th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis.The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor / C1s ratios in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 70th percentile of C1sC1 inhibitor / C1s ratios in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 75th percentile of C1sC1 inhibitor / C1s ratios in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor / C1s in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 85th percentile of C1sC1 inhibitor / C1s ratio in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 90th percentile of C1sC1 inhibitor / C1s ratio in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 95th percentile of C1sC1 inhibitor / C1s ratio in samples from lupus nephritis subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 100th percentile of C1sC1 inhibitor / C1s ratios in samples derived from age-matched lupus nephritis subjects.In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 70th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 75th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 80th percentile of the C1sC1 inhibitor / C1s in samples derived from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 85th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 90th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 95th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from normal or healthy subjects. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from normal or healthy subjects. In some embodiments, the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 70th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 75th percentile of the C1sC1 inhibitor / C1s ratio in samples from normal or healthy subjects of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 80th percentile of C1sC1 inhibitor / C1s in samples derived from normal or healthy subjects of similar age.The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 85th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 90th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 95th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject of similar age. The reference C1sC1 inhibitor / C1s ratio may be a value equal to or greater than the 100th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C1sC1 inhibitor / C1s ratio. In some embodiments, the elevated C1sC1 inhibitor / C1s ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C1sC1 inhibitor / C1s ratio.

[0408] In some embodiments, the subject has a decreased C1s level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the decreased C1s level is less than the C1s level of a normal or healthy subject. In some embodiments, the decreased C1s level is less than the C1s level of a normal or healthy subject of similar age. In some embodiments, the decreased C1s level is less than a reference C1s level. In some embodiments, the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from subjects with lupus nephritis of similar age. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples derived from subjects with lupus nephritis. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from normal or healthy subjects.In some embodiments, the reference C1s level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C1s levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the reduced C1s level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% lower than the reference C4 level. In some embodiments, the reduced C1s level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

[0409] In some embodiments, the subject has an elevated C2b level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C2b level is greater than the C2b level of a normal or healthy subject, the elevated C2b level is greater than the C2b level of a normal or healthy subject of similar age, or is greater than a reference C2b level. The reference C2b level may be a value equal to or greater than the mean or median of C2b levels in samples from subjects with lupus nephritis, or a value equal to or greater than the mean or median of C2b levels in samples from subjects with lupus nephritis of similar age. The reference C2b level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 70th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 75th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 80th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 85th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 90th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 95th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level may be a value equal to or greater than the 100th percentile of C2b levels in samples from subjects with lupus nephritis. The reference C2b level can be a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples from age-matched lupus nephritis subjects.The reference C2b level may be a value equal to or greater than the 70th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 75th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 80th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 85th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 90th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 95th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 100th percentile of C2b levels in samples from lupus nephritis subjects of similar age. The reference C2b level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C2b levels in samples from normal or healthy subjects. The reference C2b level may be a value equal to or greater than the 70th percentile of C2b levels in samples from normal or healthy subjects. The reference C2b level may be a value equal to or greater than the 75th percentile of C2b levels in samples from normal or healthy subjects. The reference C2b level may be a value equal to or greater than the 80th percentile of C2b levels in samples from normal or healthy subjects. The reference C2b level may be a value equal to or greater than the 85th percentile of the C2b level in a sample derived from a normal or healthy subject. The reference C2b level may be a value equal to or greater than the 90th percentile of the C2b level in a sample derived from a normal or healthy subject. The reference C2b level may be a value equal to or greater than the 95th percentile of the C2b level in a sample derived from a normal or healthy subject. The reference C2b level may be a value equal to or greater than the 100th percentile of the C2b level in a sample derived from a normal or healthy subject. The reference C2b level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age.The reference C2b level may be a value equal to or greater than the 70th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 75th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 80th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 85th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 90th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 95th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. The reference C2b level may be a value equal to or greater than the 100th percentile of the C2b level in a sample derived from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C2b level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300% higher than the reference C2b level. , 400% or 500% higher than the reference C2b level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference C2b level.

[0410] In some embodiments, the subject has an elevated C2b / C2 ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; decreased C2 levels; elevated C2b levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject. In some embodiments, the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject of similar age. In some embodiments, the elevated C2b / C2 ratio is greater than a reference C2b / C2 ratio. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the mean or median of the C2b / C2 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the mean or median of the C2b / C2 ratio in samples derived from lupus nephritis subjects of similar age. In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C2b / C2 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C2b / C2 ratio is equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples from normal or healthy subjects.In some embodiments, the reference C2b / C2 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in a sample from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the elevated C2b / C2 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C2b / C2 ratio. In some embodiments, the elevated C2b / C2 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C2b / C2 ratio.

[0411] In some embodiments, the subject has a decreased C2 level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the decreased C2 level is less than the C2 level of a normal or healthy subject, less than the C2 level of a normal or healthy subject of similar age, or less than a reference C2 level. The reference C2 level may be a value equal to or less than the mean or median of C2 levels in samples derived from subjects with lupus nephritis, or may be a value equal to or less than the mean or median of C2 levels in samples derived from subjects with lupus nephritis of similar age. The reference C2 level may be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile of C2 levels in samples derived from subjects with lupus nephritis. The reference C2 level can be a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C2 levels in samples from age-matched lupus nephritis subjects. The reference C2 level may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from normal or healthy subjects, or may be a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis.In some embodiments, the decreased C2 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 75000%, 80000%, 85000%, 90000%, 850000%, 90 ... %-200%, 200%-300%, 300%-400%, 400%-500% below the reference C2 level, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% below the reference C2 level.

[0412] In some embodiments, the subject has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3). In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; decreased C4 levels; elevated C1sC1 inhibitor / C1s ratio; elevated C1sC1 inhibitor levels; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated C3a levels; elevated C3a / C3 ratio; or decreased C3 levels. In some embodiments, the elevated PACA1 and / or PACA3 levels are greater than the PACA1 and / or PACA3 levels of normal or healthy subjects, greater than the PACA1 and / or PACA3 levels of normal or healthy subjects of comparable age, or greater than a reference PACA1 and / or PACA3 levels. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the mean or median of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis, or may be a value equal to or greater than the mean or median of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis of similar age. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis. The reference PACA1 and / or PACA3 level may be a value equal to or greater than the 70th percentile of PACA1 and / or PACA3 levels in samples from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 75th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 80th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 85th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 90th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis.The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 95th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 100th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 70th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 75th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 80th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 85th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 90th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 95th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 100th percentile of PACA1 and / or PACA3 levels in samples from lupus nephritis subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of PACA1 and / or PACA3 levels in samples from normal or healthy subjects.The reference PACA1 and / or PACA3 levels may be values ​​equal to or greater than the 70th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be values ​​equal to or greater than the 75th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be values ​​equal to or greater than the 80th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be values ​​equal to or greater than the 85th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be values ​​equal to or greater than the 90th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 95th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 100th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile or 100th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 70th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 75th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 80th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 85th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age. The reference PACA1 and / or PACA3 levels may be a value equal to or greater than the 90th percentile of PACA1 and / or PACA3 levels in samples derived from normal or healthy subjects of similar age.The reference PACA1 and / or PACA3 level can be a value equal to or greater than the 95th percentile of PACA1 and / or PACA3 levels in a sample derived from a normal or healthy subject of similar age. The reference PACA1 and / or PACA3 level can be a value equal to or greater than the 100th percentile of PACA1 and / or PACA3 levels in a sample derived from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis. In some embodiments, the elevated PACA1 and / or PACA3 levels are at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200% higher than the reference PACA1 and / or PACA3 levels. , 300%, 400% or 500% higher than the reference PACA1 and / or PACA3 levels, or at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference PACA1 and / or PACA3 levels.

[0413] In some embodiments, the subject has an elevated C3a level. In some embodiments, the subject has at least one of the following additional features: elevated C4x / C4 ratio; decreased C4 level; elevated C1sC1 inhibitor level; elevated C1sC1 inhibitor / C1s ratio; decreased C1s level; elevated C2b level; elevated C2b / C2 ratio; decreased C2 level; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C4x level; elevated C3a / C3 ratio; or decreased C3 level. In some embodiments, the elevated C3a level is greater than the C3a level of a normal or healthy subject. In some embodiments, the elevated C3a level is greater than the C3a level of a normal or healthy subject of similar age. In some embodiments, the elevated C3a level is greater than a reference C3a level. In some embodiments, the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from lupus nephritis subjects. In some embodiments, the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from lupus nephritis subjects of similar age. In some embodiments, the reference C3a level is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C3a levels in samples derived from lupus nephritis subjects. The reference C3a level may be a value equal to or greater than the 70th percentile of C3a levels in samples derived from lupus nephritis subjects. The reference C3a level may be a value equal to or greater than the 75th percentile of C3a levels in samples derived from lupus nephritis subjects. The reference C3a level may be a value equal to or greater than the 80th percentile of C3a levels in samples from subjects with lupus nephritis. The reference C3a level may be a value equal to or greater than the 85th percentile of C3a levels in samples from subjects with lupus nephritis. The reference C3a level may be a value equal to or greater than the 90th percentile of C3a levels in samples from subjects with lupus nephritis. The reference C3a level may be a value equal to or greater than the 95th percentile of C3a levels in samples from subjects with lupus nephritis. The reference C3a level may be a value equal to or greater than the 100th percentile of C3a levels in samples from subjects with lupus nephritis.In some embodiments, the reference C3a level is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 70th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 75th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 80th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 85th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 90th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 95th percentile of C3a levels in samples from lupus nephritis subjects of similar age. The reference C3a level may be a value equal to or greater than the 100th percentile of C3a levels in samples from lupus nephritis subjects of similar age. In some embodiments, the reference C3a level is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C3a levels in samples from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 70th percentile of C3a levels in samples from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 75th percentile of C3a levels in samples from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 80th percentile of C3a levels in samples from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 85th percentile of C3a levels in samples from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 90th percentile of C3a levels in samples derived from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 95th percentile of C3a levels in samples derived from normal or healthy subjects. The reference C3a level may be a value equal to or greater than the 100th percentile of C3a levels in samples derived from normal or healthy subjects.In some embodiments, the reference C3a level is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 70th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 75th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 80th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 85th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 90th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 95th percentile of C3a levels in samples from normal or healthy subjects of similar age. The reference C3a level may be a value equal to or greater than the 100th percentile of C3a levels in samples from normal or healthy subjects of similar age. In some embodiments, the normal or healthy subject does not suffer from lupus nephritis. In some embodiments, the elevated C3a level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C3a level. In some embodiments, the elevated C3a level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C3a level.

[0414] In some embodiments, the subject has an elevated C3a / C3 ratio. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; decreased C4 levels; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; decreased C1s levels; elevated C2b levels; elevated C2b / C2 ratio; decreased C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C4x / C4 ratio; or decreased C3 levels. In some embodiments, the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject. In some embodiments, the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject of similar age. In some embodiments, the elevated C3a / C3 ratio is greater than the reference C3a / C3 ratio. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the mean or median of the C3a / C3 ratio in samples derived from lupus nephritis subjects. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the mean or median of the C3a / C3 ratio in samples derived from lupus nephritis subjects of similar age. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C3a / C3 ratio in samples derived from lupus nephritis subjects. The reference C3a / C3 ratio may be a value equal to or greater than the 70th percentile of the C3a / C3 ratio in samples derived from lupus nephritis subjects. The reference C3a / C3 ratio may be a value equal to or greater than the 75th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis. The reference C3a / C3 ratio may be a value equal to or greater than the 80th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis. The reference C3a / C3 ratio may be a value equal to or greater than the 85th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis. The reference C3a / C3 ratio may be a value equal to or greater than the 90th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis. The reference C3a / C3 ratio may be a value equal to or greater than the 95th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis. The reference C3a / C3 ratio may be a value equal to or greater than the 100th percentile of the C3a / C3 ratio in a sample derived from a subject with lupus nephritis.In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 70th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 75th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 80th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 85th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 90th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 95th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 100th percentile of the C3a / C3 ratio in samples from lupus nephritis subjects of similar age. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 70th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 75th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 80th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 85th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 90th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject.The reference C3a / C3 ratio may be a value equal to or greater than the 95th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. The reference C3a / C3 ratio may be a value equal to or greater than the 100th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject. In some embodiments, the reference C3a / C3 ratio is a value equal to or greater than the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 95th percentile, or 100th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 70th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 75th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 80th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 85th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 90th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 95th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. The reference C3a / C3 ratio may be a value equal to or greater than the 100th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject of similar age. In some embodiments, the normal or healthy subject does not have lupus nephritis.In some embodiments, the elevated C3a / C3 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C3a / C3 ratio.In some embodiments, the elevated C3a / C3 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C3a / C3 ratio.

[0415] In some embodiments, the subject has a reduced C3 level. In some embodiments, the subject has at least one of the following additional features: elevated C4x levels; elevated C4x / C4 ratio; elevated C1sC1 inhibitor levels; elevated C1sC1 inhibitor / C1s ratio; reduced C1s levels; elevated C2b levels; elevated C2b / C2 ratio; reduced C2 levels; elevated pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3) levels; elevated C3a levels; elevated C3a / C3 ratio; or reduced C4 levels. In some embodiments, the reduced C3 level is less than the C3 level of a normal or healthy subject. In some embodiments, the reduced C3 level is less than the C3 level of a normal or healthy subject of similar age. In some embodiments, the reduced C3 level is less than a reference C3 level. In some embodiments, the reference C3 level is equal to or less than the mean or median value of the C3 level in the sample derived from a subject with lupus nephritis. In some embodiments, the reference C3 level is equal to or less than the mean or median value of the C3 level in the sample derived from a subject with lupus nephritis of similar age. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile value of the C3 level in the sample derived from a subject with lupus nephritis. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples from age-matched lupus nephritis subjects. In some embodiments, the reference C3 level is equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples from normal or healthy subjects. In some embodiments, the reference C3 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples derived from normal or healthy subjects of similar age.In some embodiments, the normal or healthy subject does not have lupus nephritis. In some embodiments, the reduced C3 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% lower than the reference C4 level. In some embodiments, the reduced C3 level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

[0416] In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured in a biological sample. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured in plasma or urine. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 12 months prior to administration of a therapeutically effective amount of an inhibitor of the classical complement pathway. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 6 months prior to administration of an inhibitor. In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 3 months prior to administration of an inhibitor.In some embodiments, the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured less than about 1 month prior to administration of an inhibitor.

[0417] In some embodiments, the subject has an elevated urine protein / creatinine ratio (UPCR) level. In some embodiments, the elevated UPCR level is greater than the UPCR level of a normal or healthy subject, greater than the UPCR level of a normal or healthy subject of similar age, or greater than a reference UPCR level. The reference UPCR level may be equal to or greater than about 0.5 g / g, 1.0 g / g, 1.5 g / g, 2.0 g / g, 2.5 g / g, 3.0 g / g, 3.5 g / g, 4.0 g / g, 4.5 g / g, or 5.0. The elevated UPCR level may be at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000%, or 5000% higher than the UPCR level in a normal or healthy subject or the reference UPCR level. The elevated UPCR level may be at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, 400%-500%, 500%-600%, 600%-700%, 700%-800%, 800%-900%, 900%-1000%, 1000%-2000%, 2000%-3000%, 3000%-4000%, or 4000-5000% higher than the UPCR level in a normal or healthy subject or the reference UPCR level. In some embodiments, the UPCR levels are measured in urine.

[0418] In some embodiments, the classical complement inhibitor is a C1 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent. In some embodiments, the antibody is a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a humanized antibody, a chimeric antibody, a multispecific antibody or an antibody derivative thereof.

[0419] In some embodiments, the inhibitor of the classical complement pathway is a C1q inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent. In some embodiments, the antibody is a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a humanized antibody, a chimeric antibody, a multispecific antibody or an antibody derivative thereof. The antibody may be an anti-C1q antibody. In some embodiments, the antibody derivative thereof is a one-armed antibody.

[0420] In some embodiments, the antibody is administered at a dose of at least 50 mg / kg, or at a dose between 50 mg / kg and 200 mg / kg. The antibody can be administered in an amount of 50 mg / kg, 55 mg / kg, 60 mg / kg, 65 mg / kg, 70 mg / kg, 75 mg / kg, 80 mg / kg, 85 mg / kg, 90 mg / kg, 95 mg / kg, 100 mg / kg, 105 mg / kg, 110 mg / kg, 115 mg / kg, 120 mg / kg, 125 mg / kg, 130 mg / kg, 135 mg / kg, 140 mg / kg, 145 mg / kg, 150 mg / kg, 155 mg / kg, 160 mg / kg, 165 mg / kg, 170 mg / kg, 175 mg / kg, 180 mg / kg, 185 mg / kg, 190 mg / kg, 195 mg / kg or 200 mg / kg. In some embodiments, the antibody is administered in an amount of at least 50 mg. The antibody can be administered at a total dose of 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 105 mg, 110 mg, 115 mg, 120 mg, 125 mg, 130 mg, 135 mg, 140 mg, 145 mg, 150 mg, 155 mg, 160 mg, 165 mg, 170 mg, 175 mg, 180 mg, 185 mg, 190 mg, 195 mg or 200 mg. In some embodiments, the antibody is administered daily, weekly, every other week, monthly, every six weeks, or every other month. In some embodiments, the antibody is administered for at least 3 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months, preferably at least 6 months. The antibody can be administered throughout the patient's life, or intermittently throughout the patient's life, for example in response to fever. In some embodiments, the antibody is administered at a dose of 75 mg / kg on day 1 and on day 5 or day 6. In some embodiments, the antibody is further administered at a dose of 100 mg / kg every two weeks. In some embodiments, the antibody is administered intravenously.

[0421] In some embodiments, the antibody is an antibody fragment, such as a Fab fragment, a Fab' fragment, a F(ab')2 fragment, a Fv fragment, a diabody or a single-chain antibody molecule. In some embodiments, the antibody fragment is administered at a total dose of at least 250 mg or at a total dose between 250 mg and 1000 mg. In some embodiments, the antibody fragment is administered at a total dose of 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, 500 mg, 525 mg, 550 mg, 575 mg, 600 mg, 625 mg, 650 mg, 675 mg, 700 mg, 725 mg, 750 mg, 775 mg, 800 mg, 825 mg, 850mg, 875mg, 900mg, 925mg, 950mg, 975mg, 1000mg, 1250mg, 1275mg, 1300mg, 1325mg, 1350mg, 13 75mg, 1400mg, 1425mg, 1450mg, 1475mg, 1500mg, 1525mg, 1550mg, 1575mg, 1600mg, 1625mg, 1650mg , 1675mg, 1700mg, 1725mg, 1750mg, 1775mg, 1800mg, 1825mg, 1850mg, 1875mg, 1900mg, 1925mg, 19 50mg, 1975mg, 2000mg, 2250mg, 2275mg, 2300mg, 2325mg, 2350mg, 2375mg, 2400mg, 2425mg, 2450mg , 2475mg, 2500mg, 2525mg, 2550mg, 2575mg, 2600mg, 2625mg, 2650mg, 2675mg, 2700mg, 2725mg, 2750mg, 2775mg, 2800mg, 2825mg, 2850mg, 2875mg, 2900mg, 2925mg, 2950mg, 2975mg or 3000mg total dose is administered. In some embodiments, the antibody fragment is administered with a total dose of about 750mg. In some embodiments, the antibody fragment is administered daily, once every other day, once every three days, once every four days, once every five days or once every six days, once a week, once every two weeks or once a month. In some embodiments, the antibody fragment is administered three times a week. In some embodiments, the antibody fragment is administered for at least 3 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months. The antibody fragment can be administered throughout the patient's life, or intermittently throughout the patient's life, for example in response to fever.In some embodiments, the antibody fragment is administered subcutaneously.

[0422] In some embodiments, the anti-C1q antibody inhibits the interaction between C1q and autoantibodies, or between C1q and C1r, or between C1q and C1s, and / or promotes the clearance of C1q from the circulation or tissues. In some embodiments, the antibody comprises: a light chain variable domain comprising HVR-L1 having an amino acid sequence of SEQ ID NO:5, HVR-L2 having amino acids of SEQ ID NO:6, and HVR-L3 having amino acids of SEQ ID NO:7; and / or a heavy chain variable domain comprising HVR-H1 having an amino acid sequence of SEQ ID NO:9, HVR-H2 having amino acids of SEQ ID NO:10, and HVR-H3 having amino acids of SEQ ID NO:11. In some embodiments, the antibody comprises a light chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NOs:4 and 35-38, and wherein the light chain variable domain comprises HVR-L1 having an amino acid sequence of SEQ ID NO:5, HVR-L2 having amino acids of SEQ ID NO:6, and HVR-L3 having amino acids of SEQ ID NO:7, preferably the light chain variable domain comprises an amino acid sequence selected from SEQ ID NOs:4 and 35-38. In some embodiments, the antibody comprises a heavy chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NO: 8 and 31-34, and wherein the heavy chain variable domain comprises an HVR-H1 having an amino acid sequence of SEQ ID NO: 9, an HVR-H2 having an amino acid of SEQ ID NO: 10, and an HVR-H3 having an amino acid of SEQ ID NO: 11, preferably the heavy chain variable domain comprises an amino acid sequence selected from SEQ ID NO: 8 and 31-34. In some embodiments, the antibody comprises a light chain domain comprising an amino acid sequence of SEQ ID NO: 40; a first heavy chain domain comprising an amino acid sequence of SEQ ID NO: 2; and a second heavy chain domain comprising an amino acid sequence of SEQ ID NO: 3; the second heavy chain domain is an N-terminally truncated heavy chain. In some embodiments, the antibody fragment comprises a heavy chain Fab fragment of SEQ ID NO: 39 and a light chain Fab fragment of SEQ ID NO: 40.

[0423] In some embodiments, the inhibitor of the classical complement pathway is a C1r inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent, preferably an anti-C1r antibody. In some embodiments, the anti-C1r antibody inhibits the interaction between C1r and C1q or between C1r and C1s, or wherein the anti-C1r antibody inhibits the catalytic activity of C1r, or it inhibits the processing of C1r into an active protease.

[0424] In some embodiments, the inhibitor of the classical complement pathway is a C1s inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent, preferably an anti-C1s antibody. In some embodiments, the anti-C1s antibody inhibits the interaction between C1s and C1q, or between C1s and C1r, or between C1s and C2 or C4, or wherein the anti-C1s antibody inhibits the catalytic activity of C1s, or it inhibits the processing of pro-C1s into an active protease, or it binds to an activated form of C1s. In some embodiments, the antibody is sutimlimab.

[0425] In some embodiments, the inhibitor of the classical complement pathway is an anti-C1 complex antibody, optionally wherein the anti-C1 complex antibody inhibits C1r or C1s activation or blocks their ability to act on C2 or C4. The anti-C1 complex antibody binds to a combinatorial epitope within the C1 complex, wherein the combinatorial epitope comprises amino acids of both C1q and C1s; amino acids of both C1q and C1r; amino acids of both C1r and C1s; or amino acids of each of C1q, C1r, and C1s.

[0426] In some embodiments, the inhibitor of the classical complement pathway is a C2 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent. The C2 inhibitor can be ARGX-117 (Argenx).

[0427] In some embodiments, the inhibitor of the classical complement pathway is a C3 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid or a gene editing agent. The C3 inhibitor can be APL-9 (Apellis) or AMY-101 (Amyndas).

[0428] In some embodiments, the inhibitor of the classical complement pathway is a C4 inhibitor, such as a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

[0429] Example

[0430] Example 1: Improved Model for Prediction and Treatment of Lupus

[0431] We observed evidence of complement activation in patients with lupus nephritis relative to healthy controls. Specifically, the levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, and the ratios of C4a / C4, C4d / C4, C1sC1 inhibitor / C1s, C2b / C2, and C3a / C3 were significantly increased in patients with lupus nephritis, whereas the levels of C4, C1s, C2, and C3 were decreased in patients with lupus nephritis. More specifically, we observed a significant increase in the levels of C4d and the C4d / C4 ratio in the setting of fever, whereas the levels of C1q, C1s, C2, and C4 were decreased in patients with lupus nephritis, consistent with activation of the classical complement pathway (increased activation and consumption of components). The C4d / C4 ratio also correlated with the levels of autoantibodies against C1q isoforms 1 and 3, which are known to activate the classical pathway. These data suggest that a subset of LN patients who exhibit high C4d / C4 ratios and specific markers of classical pathway activation may benefit from classical complement inhibitors, or more specifically, anti-C1q therapy. In addition, these data suggest that a subset of LN patients who exhibit high levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, C4a / C4, gC1sC1 inhibitor / C1s, and C2b / C2, or reduced levels of C4, C1s, C2 may benefit from therapy with classical complement inhibitors, or more specifically, anti-C1q therapy.

[0432] Table 1 shows the biomarker panel of plasma using ELISA.

[0433]

[0434] Patient demographics Figure 3 SELENA-SLEDAI uses an overall disease activity target. It assesses disease activity by scoring 24 weighted disease activity descriptors of SLE as "present" or "absent" in the previous 10 days. See Bombardier C et al., Arthritis Rheum 1992; Petri M. Ann Rheum Dis 2007; Petri et al., N. Engl J Med 2005.

[0435] The following results were obtained. The C4d / C4 ratio is elevated in patients with lupus nephritis (LN), suggesting a role for the classical complement pathway in mediating the disease. Classical complement pathway activation is enriched in LN. C1 inhibitor is upregulated in LN patients, likely due to chronic complement activation. There is a high correlation between complement factors in LN. PACA (pathogenic anti-C1q antibody) levels are associated with classical complement activation in patients with lupus nephritis. Improvement in the C4d / C4 ratio after treatment further supports the relevance of the complement pathway in disease pathology. Clinical C4 measurements track the UPCR (urine protein / creatine ratio) trajectory. In this dataset, the C4d / C4 ratio is driven to low C4 (indicating that patients do not have a high C4 copy number). In patients with high disease activity, the C4d / C4 ratio decreases temporarily. But their levels remain high relative to patients with low disease activity and healthy controls.

[0436] Classical complement pathway activation is enriched in LNs.

[0437] The higher circulating C4d / C4 ratio in patients with active LN suggests that complement may drive disease progression and severity ( Figure 4 LN patients with high C4d / C4 ratios exhibit coordinated classical complement activation ( Figure 5 ). The data showed that compared with healthy controls, LN patients had decreased classical pathway substrates and increased products.

[0438] Furthermore, high circulating levels of C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, and the C2b / C2 ratio, C1sC1 inhibitor / C1s ratio, and C3a / C3 ratio, as well as decreased levels of C4, C2, C1s, and C3 in patients with active LN suggest that complement may drive disease progression and severity. Fig.21A -O).

[0439] High correlation between complement factors in LN.

[0440] The high correlation between complement factors in LN patients suggests coordinated pathway activity ( Figure 6 and Fig. 22 No association was observed in the healthy control group ( Figure 7 ). The data showed a strong association between a high C4d / C4 ratio and the presence of PACA. The data also showed strong associations between other complement factors in LN patients, for example, C4d / C4 and C4d had a strong positive correlation, and C2b and C2b / C2 had a strong inverse correlation ( Fig. 22 ). This correlation is used to select patients most likely to respond to therapy with the classical complement pathway, more specifically anti-C1q therapy.

[0441] PACA levels are associated with classical complement activation in patients with lupus nephritis

[0442] PACA1 levels remain elevated throughout treatment. Patients with active LN who have a high C4d / C4 ratio may have higher PACA1 ( Figure 8A-B ). PACA1 may be an additional factor that amplifies disease severity. A subset of patients with high PACA do not have low C4.

[0443] Improvements in the C4d / C4 ratio following treatment further support the relevance of the complement pathway in disease pathology

[0444] According to standard of care, C4d / C4 is reduced after a febrile event, but the effect is not sustained ( Fig. 9 ). Fig.10 Changes in urine protein / creatinine ratio (UPCR) and C4 in response to standard of care treatment are shown. An increase in C4 levels is approximately equivalent to a decrease in C4d / C4 (C4d is new and not routinely monitored). An increase in C4 levels is consistent with an improvement in UPCR. A decrease in C4 levels after a febrile episode indicates residual inflammation that may lead to a recurrence of fever.

[0445] Anti-C1q therapy, such as anti-C1q Fab (eg, FabA), has the opportunity to improve the depth and durability of responses in these patients by preventing the activation of complement. Anti-C1q Fab (FabA) may increase the proportion of complete responders by directly targeting classical complement.

[0446] The data also showed that clinical C4 measurements tracked UPCR trajectories ( Fig.11 Increased C4 and decreased C4d / C4 were associated with improved disease activity ( Fig.12 ).

[0447] Summarize

[0448] In a cohort of 40 LN patients, C4a, C4d, C1sC1 inhibitor, C3a, PACA1, PACA3, and C4a / C4, C4d / C4, C2b / C2, C3a / C3, and C1sC1 inhibitor / C1s ratios were found to be higher than healthy controls, especially those with active disease, suggesting involvement of classical complement activation in disease pathology. In addition, C4, C1s, C2, and C3 were found to be lower than healthy controls, especially those with active disease, also suggesting involvement of classical complement activation in disease pathology. There is correlative evidence that PACA1 amplifies disease severity. Standard of care does not normalize C4d / C4 in nonresponders, suggesting that existing treatments do not address the underlying cause of disease in these patients. Patients with high C4d / C4 benefit from therapies targeting C1q, thereby inhibiting activation of disease-mediated pathways. Selecting patients with C4d / C4 provides the opportunity to target patients with complement activation as a key disease driver, thus most likely to have an improved outcome, and to identify patients in earlier disease states, potentially with better outcomes. Selecting patients with at least elevated C4a, C4d, C1sC1 inhibitor, PACA1, PACA3, and C4a / C4 ratio, C2b / C2 ratio, and C1sC1 inhibitor / C1s ratio, and decreased C4, C2, and C1s levels also provides the opportunity to target patients with complement activation as a key disease driver, thus most likely to have an improved outcome, and to identify patients in earlier disease states, potentially with better outcomes.

[0449] Example 2: Evaluation of adult participants with lupus nephritis with repeated standard of care therapy A single-arm, phase 1b, open-label study of the safety, tolerability, and pharmacodynamics of subcutaneous FabA at a dose of

[0450] The study included a screening period of up to 8 weeks (56 days), an intervention period of approximately 3 weeks (22 days), and a non-treatment follow-up period of approximately 11 weeks (80 days). The maximum duration of participation was approximately 158 days (approximately 23 weeks). Participants received FabA 750 mg via a SC infusion pump 3 times a week, with no more than 3 days between dosing. The total dose administered in this LN study was within the safety range established in nonclinical toxicology studies. It is noteworthy that in a 4-week nonclinical GLP toxicology study conducted in cynomolgus monkeys, no safety findings were observed at SC doses equivalent to a human dose of 1500 mg per day (no adverse effect level [NOAEL] was observed at 20 mg / kg per day, the highest dose tested), during which complete C1q inhibition was observed in serum during the dosing interval.

[0451] Screening Visits (Weeks 8, 6, and 2): All participants underwent study screening procedures within 56 days prior to dosing with Fab A. A renal biopsy was required for those participants who did not have a renal biopsy within 24 months of screening.

[0452] This study investigated the safety and PD efficacy of FabA administered by SC infusion pump in participants with ISN / RPS grade III / IV (± V) LN. Participants with proteinuria in the range of 0.5-3.0 g / g / day using UPCR and evidence of classical complement activation (high C4d / C4 ratio) received FabA in addition to stable standard of care therapy. This population was considered to have an incomplete renal response despite prior induction therapy with therapeutic agents such as cyclophosphamide, MMF, rituximab, and glucocorticoids.

[0453] High C4d / C4 ratios were used to identify LN participants with classical complement pathway activation and ongoing renal inflammation. Approximately half of LN patients with high C4d / C4 ratios had proteinuria in the range of 0.5-3.0 g / g / day (the remainder had proteinuria >3.0 g / g / day), suggesting residual renal disease activity.

[0454] Collect samples (saliva or existing blood samples) for genetic studies related to this study.

[0455] All participants received FabA 750 mg SC 3 times per week for approximately 3 weeks (10 doses) administered via SC infusion pump with no more than 3 days between doses.

[0456] Example 3: PACA plasma titer is correlated with the degree of renal damage in patients with lupus nephritis

[0457] PACA plasma titers correlated with the extent of renal damage in patients with lupus nephritis, as assessed by the urine protein / creatinine ratio (UPCR) as a measure of proteinuria. PACA of the IgG1 and IgG3 isotypes provided the strongest correlation with UPCR, whereas no significant correlation was observed with levels of IgG2 and IgG4 antibodies to C1q ( Fig.13 ). These results are important because IgG1 and IgG3 are the antibody isotypes that most strongly recruit additional C1q (complement fixing isotypes), whereas IgG2 and IgG4 will recruit little or no C1q to immune complexes and therefore are not associated with increased levels of disease. Although IgM antibodies strongly activate C1q, they are characteristic of acute disease and would not be expected to circulate at appreciable levels in chronic conditions such as lupus nephritis. PACA1 and PACA3 levels also correlate with C4d and the C4d / C4 ratio ( Fig.14 ).

[0458] In addition, early studies in animal models of lupus nephritis reported a causal relationship between anti-C1q antibodies and renal damage. Administration of PACA significantly exacerbated the disease, with a large increase in complement deposition in the glomerular subendothelial space ( Fig.17 and Fig.18 PACA is also characterized by its ability to selectively bind substrate-bound C1q and activate the classical complement pathway. The binding of PACA to substrate-bound C1q is not affected by soluble C1q ( Fig.19 ). Thus, PACA correlates with disease severity and is a complement activator of the IgG1 and IgG3 isotypes, whereas IgG4 does not fix C1q. Anti-C1q IgG1 and IgG3, but not IgG4 levels, correlate with serum C4d / C4 ratios ( Fig. 20 ). This is consistent with the complement activation capacity of the antibody isotype.

[0459] Complement factor C4 and its activation product C4d are important biomarkers of LN. Reduced levels of C4 and increased amounts of C4d in the circulation indicate activation of the classical complement pathway and are associated with active LN. The level of C4d in plasma is closely related to C4d deposition in renal tissue from patients with active LN. Compared with SLE patients without LN, patients with autoimmune kidney disease IgA nephropathy, and healthy controls, the C4d / C4 ratio of active LN is increased. In addition, the C4d / C4 ratio predicts the presence of active LN more accurately than other biomarkers (e.g., C3, C4, and C4d). Therefore, C4d / C4 can identify active LN patients who are most likely to respond to therapies targeting the classical complement cascade.

[0460] In summary, these data provide a strong scientific and clinical rationale for evaluating anti-C1q therapy in patients with grade III / IV LN with evidence of classical complement pathway activation.

[0461] Embodiment 4: To evaluate the efficacy of repeat therapy in adult participants with lupus nephritis A single-arm, phase 1b, open-label study of the safety, tolerability, and pharmacodynamics of subcutaneous FabA at a dose of

[0462] The study included a screening period of up to 8 weeks (56 days), an intervention period of approximately 3 weeks (22 days), and a non-treatment follow-up period of approximately 11 weeks (80 days). The maximum duration of participation was approximately 158 days (approximately 23 weeks). Participants received FabA 750 mg via a SC infusion pump 3 times a week, with no more than 3 days between dosing. The total dose administered in this LN study was within the safety range established in nonclinical toxicology studies. It is noteworthy that in a 4-week nonclinical GLP toxicology study conducted in cynomolgus monkeys, no safety findings were observed at SC doses equivalent to a human dose of 1500 mg per day (no adverse effect level [NOAEL] was observed at 20 mg / kg per day, the highest dose tested), during which complete C1q inhibition was observed in serum during the dosing interval.

[0463] Screening Visits (Weeks 8, 6, and 2): All participants underwent study screening procedures within 56 days prior to dosing with Fab A. A renal biopsy was required for those participants who did not have a renal biopsy within 24 months of screening.

[0464] This study investigated the safety and PD efficacy of FabA administered by SC infusion pump in participants with ISN / RPS grade III / IV (± V) LN. Participants with proteinuria in the range of 0.5-3.0 g / g / day using UPCR and evidence of classical complement activation (high C4d / C4 ratio) received FabA in addition to stable standard of care therapy. This population was considered to have an incomplete renal response despite prior induction therapy with therapeutic agents such as cyclophosphamide, MMF, rituximab, and glucocorticoids.

[0465] High C4d / C4 ratios were used to identify LN participants with classical complement pathway activation and ongoing renal inflammation. High C4d / C4 ratios in this study were defined as LN patients with a C4d / C4 ratio equal to or greater than the median in samples derived from LN subjects. Approximately half of LN patients with high C4d / C4 ratios had proteinuria in the range of 0.5-3.0 g / g / day (proteinuria>3.0 g / g / day in the remaining patients), indicating residual renal disease activity.

[0466] Collect samples (saliva or existing blood samples) for genetic studies related to this study.

[0467] All participants received FabA 750 mg SC 3 times per week for approximately 3 weeks (10 doses) administered via SC infusion pump with no more than 3 days between doses.

[0468] Four patients completed treatment and are currently screening. Interim data showed that in all four patients, the C4d / C4 ratio decreased with treatment and returned to baseline after discontinuation of treatment ( Fig.23A ). Furthermore, inhibition of C1q resulted in normalization of downstream markers including C3 and C59b, indicating that the classical pathway is an important driver of complement activation in these LN patients ( Fig. 23B -F). In this short-term treatment study, no consistent trend in urine protein-creatinine ratio was observed.

[0469] In this interim analysis, subcutaneously administered FabA was well tolerated and demonstrated C1q target engagement and complement inhibition in four patients. Furthermore, normalization of all downstream components, including C3 and C59-b, suggests that the classical pathway is a key driver of complement activation in these LN patients. These interim results support the use of anti-C1q therapy in a subset of LN patients.

[0470] Example 5: General Methods

[0471] Complement protein C4d was measured using the SVAR C4d ELISA kit (SVAR, COMPL C4d RUO). Levels of PACA 1, PACA3 and complement proteins C1s, C1sC1inh, C2, C2b, C4, C4a, C3, C3a and C3d were measured in plasma samples using sandwich ELISA.

[0472] Black 96-well plates (Costar #3925) were coated with 75 μL of 2-3 μg / mL capture antibody in bicarbonate buffer (pH 9.4) overnight at 4° C. The next day, the plates were washed with dPBS (pH 7.4) and blocked with dPBS buffer containing 3% bovine serum albumin (BSA). Standards of complement proteins C1s, C1sC1inh, C2, C2b, C4, C4a, C3, C3a, and C3d were purchased from Complement Tech and prepared in dPBS containing 0.3% BSA, 0.01 M EDTA, and 0.1% tween (assay buffer, respectively) in the ranges of 100-0.045, 1000-0.45, 200-0.09, 30-0.013, 100-0.04, 500-0.22, 100-0.045, 0.5-0.004, and 50-0.002 ng / mL. PACA1 (ATUM, 63044) and PACA3 (ATUM, 63050) standards were prepared in the range of 300-0.02 ng / mL in dPBS containing 0.3% BSA, 0.01M EDTA, 0.1% tween and 1M NaCl (high salt assay buffer). Plasma samples were diluted in the range of 30000 (C1s), 90 (C1sC1inh), 8000 (C2), 2000 (C2b), 400,000 (C4), 200 (C4a), 200000 (C3), 50000 (C3a), 200000 (C3d) of the assay buffer to 20 (PACA 1, PACA3) of the above high salt assay buffer.

[0473] After one hour of incubation, the blocking buffer was removed from the plate. Standards and samples were added with 75 μL per well and incubated overnight at 300 rpm with shaking at 4 ° C. The plate was then washed three times with dPBS containing 0.05% Tween. Then, 75 μL of appropriate alkaline phosphatase-conjugated detection antibodies were added to all wells. The plate was incubated at room temperature with shaking for 1 hour, washed three times with dPBS containing 0.05% Tween, and then developed using 75 μL alkaline phosphatase substrate (Life Technologies, T2214). After 20 minutes of incubation, the plate was read using a photometer. Standards were fitted using 4PL logical fitting, and unknown quantities were converted to concentrations, dilutions were corrected, and then appropriate drawing software was used to draw, in some of these embodiments, the software was GraphPad Prism.

[0474] Incorporated by Reference

[0475] All publications, patents, and patent applications mentioned herein are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In the event of a conflict, the present application, including any definitions herein, will control.

[0476] Equivalent solutions

[0477] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

1. A method of treating lupus nephritis in a subject in need thereof, the method comprising: The subject is determined to have at least one of the following characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Elevated C1sC1 inhibitor levels; e. Increased C1sC1 inhibitor / C1s ratio; f. Reduced C1s levels; g. Elevated C2b levels; h. Increased C2b / C2 ratio; i. Reduced C2 levels; or j. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); wherein C4x is selected from the group consisting of C4a and C4d, and An inhibitor of the classical complement pathway is administered to the subject.

2. The method of claim 1, wherein the subject has at least two of the characteristics.

3. The method of claim 2, wherein the characteristic is selected from the group consisting of elevated C4x levels, elevated C4x / C4 ratio, and decreased C4 levels.

4. The method of claim 2, wherein the characteristic is selected from the group consisting of elevated C1sC1 inhibitor levels, elevated C1sC1 inhibitor / C1s ratios, and decreased C1s levels.

5. The method of claim 3 or 4, wherein the subject further has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3).

6. The method of any one of claims 1 to 5, wherein the subject has at least one of the following additional characteristics: a. Elevated C3a levels; b. Elevated C3a / C3 ratio; or c. Reduced C3 levels.

7. The method of claim 1, wherein the subject has elevated C4x levels.

8. The method of claim 7, wherein the subject has at least one of the following additional characteristics: a. Increased C4x / C4 ratio; b. Reduced C4 levels; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

9. The method of any one of claims 1 to 8, wherein the elevated C4x level is greater than the C4x level of a normal or healthy subject.

10. The method of any one of claims 1 to 8, wherein the elevated C4x level is greater than the C4x level of a normal or healthy subject of comparable age.

11. The method of any one of claims 1 to 10, wherein the elevated C4x level is greater than a reference C4x level. 12 . The method of claim 11 , wherein the reference C4x level is a value equal to or greater than the mean or median of C4x levels in samples derived from subjects with lupus nephritis.

13. The method of claim 11, wherein the reference C4x level is a value equal to or greater than the mean or median of C4x levels in samples derived from age-matched lupus nephritis subjects.

14. The method of claim 11, wherein the reference C4x level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples derived from subjects with lupus nephritis.

15. The method of claim 11, wherein the reference C4x level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples from age-matched lupus nephritis subjects.

16. The method of claim 11, wherein the reference C4x level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in a sample derived from a normal or healthy subject.

17. The method of claim 11, wherein the reference C4x level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x levels in samples derived from normal or healthy subjects of similar age.

18. The method of any one of claims 12 to 17, wherein the normal or healthy subject does not suffer from lupus nephritis.

19. The method of any one of claims 7 to 18, wherein the elevated C4x level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C4x level.

20. The method of any one of claims 7 to 18, wherein the elevated C4x level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C4x level.

21. The method of claim 1, wherein the subject has an elevated C4x / C4 ratio.

22. The method of claim 21, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Reduced C4 levels; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

23. The method of any one of claims 1 to 22, wherein the elevated C4x / C4 ratio is greater than the C4x / C4 ratio of a normal or healthy subject.

24. The method of any one of claims 1 to 22, wherein the elevated C4x / C4 ratio is greater than the C4x / C4 ratio of a normal or healthy subject of comparable age.

25. The method of any one of claims 1 to 24, wherein the elevated C4x / C4 ratio is greater than a reference C4x / C4 ratio.

26. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the mean or median of C4x / C4 ratios in samples derived from subjects with lupus nephritis.

27. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the mean or median of C4x / C4 ratios in samples derived from age-matched lupus nephritis subjects.

28. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in samples derived from subjects with lupus nephritis.

29. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C4x / C4 ratios in samples from age-matched lupus nephritis subjects.

30. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in a sample derived from a normal or healthy subject.

31. The method of claim 25, wherein the reference C4x / C4 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C4x / C4 ratio in a sample derived from normal or healthy subjects of similar age.

32. The method of any one of claims 26 to 31, wherein the normal or healthy subject does not suffer from lupus nephritis.

33. The method of any one of claims 25 to 32, wherein the elevated C4x / C4 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C4x / C4 ratio.

34. The method of any one of claims 25 to 32, wherein the elevated C4x / C4 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C4x / C4 ratio.

35. The method of claim 1, wherein the subject has decreased C4 levels.

36. The method of claim 35, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

37. The method of any one of claims 1 to 36, wherein the reduced C4 level is less than the C4 level of a normal or healthy subject.

38. The method of any one of claims 1 to 36, wherein the reduced C4 level is less than the C4 level of a normal or healthy subject of comparable age.

39. The method of any one of claims 36 to 38, wherein the reduced C4 level is less than a reference C4 level.

40. The method of claim 39, wherein the reference C4 level is a value equal to or less than the mean or median of C4 levels in samples derived from subjects with lupus nephritis.

41. The method of claim 39, wherein the reference C4 level is a value equal to or less than the mean or median of C4 levels in samples derived from age-matched lupus nephritis subjects.

42. The method of claim 39, wherein the reference C4 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in samples derived from subjects with lupus nephritis.

43. The method of claim 39, wherein the reference C4 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C4 levels in samples from age-matched lupus nephritis subjects.

44. The method of claim 39, wherein the reference C4 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C4 levels in a sample derived from a normal or healthy subject.

45. The method of claim 39, wherein the reference C4 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C4 levels in samples derived from normal or healthy subjects of similar age.

46. ​​The method of any one of claims 40 to 45, wherein the normal or healthy subject does not suffer from lupus nephritis.

47. The method of any one of claims 35 to 46, wherein the decreased C4 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% lower than the reference C4 level.

48. The method of any one of claims 35 to 46, wherein the decreased C4 level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

49. The method of claim 1, wherein the subject has elevated levels of C1sC1 inhibitor.

50. The method of claim 49, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

51. The method of any one of claims 1 to 50, wherein the elevated C1sC1 inhibitor level is greater than the C1sC1 inhibitor level of a normal or healthy subject.

52. The method of any one of claims 1 to 50, wherein the elevated C1sC1 inhibitor level is greater than the C1sC1 inhibitor level in a normal or healthy subject of comparable age.

53. The method of any one of claims 1 to 52, wherein the elevated C1sC1 inhibitor level is greater than a reference C1sC1 inhibitor level.

54. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis.

55. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the mean or median of C1sC1 inhibitor levels in samples derived from age-matched lupus nephritis subjects.

56. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples derived from subjects with lupus nephritis.

57. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples from age-matched subjects with lupus nephritis.

58. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples derived from normal or healthy subjects.

59. The method of claim 53, wherein the reference C1sC1 inhibitor level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C1sC1 inhibitor levels in samples derived from normal or healthy subjects of similar age.

60. The method of any one of claims 51 to 59, wherein the normal or healthy subject does not suffer from lupus nephritis.

61. The method of any one of claims 53 to 60, wherein the elevated C1sC1 inhibitor level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C1sC1 inhibitor level.

62. The method of any one of claims 53 to 60, wherein the elevated C1sC1 inhibitor level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C1sC1 inhibitor level.

63. The method of claim 1, wherein the subject has an elevated C1sC1 inhibitor / C1s ratio.

64. The method of claim 63, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Reduced C4 levels; c. Increased C4x / C4 ratio; d. Elevated C1sC1 inhibitor levels; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

65. The method of any one of claims 1 to 64, wherein the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject.

66. The method of any one of claims 1 to 65, wherein the elevated C1sC1 inhibitor / C1s ratio is greater than the C1sC1 inhibitor / C1s ratio of a normal or healthy subject of comparable age.

67. The method of any one of claims 1 to 64, wherein the elevated C1sC1 inhibitor / C1s ratio is greater than a reference C1sC1 inhibitor / C1s ratio.

68. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from subjects with lupus nephritis.

69. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the mean or median of C1sC1 inhibitor / C1s ratios in samples derived from age-matched lupus nephritis subjects.

70. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from subjects with lupus nephritis.

71. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples from age-matched lupus nephritis subjects.

72. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in a sample derived from a normal or healthy subject.

73. The method of claim 67, wherein the reference C1sC1 inhibitor / C1s ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C1sC1 inhibitor / C1s ratio in samples derived from age-matched normal or healthy subjects.

74. The method of any one of claims 65 to 73, wherein the normal or healthy subject does not have lupus nephritis.

75. The method of any one of claims 67 to 74, wherein the elevated C1sC1 inhibitor / C1s ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C1sC1 inhibitor / C1s ratio.

76. The method of any one of claims 67 to 74, wherein the elevated C1sC1 inhibitor / C1s ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C1sC1 inhibitor / C1s ratio.

77. The method of claim 1, wherein the subject has decreased C1s levels.

78. The method of claim 77, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Elevated C1sC1 inhibitor levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

79. The method of any one of claims 1 to 78, wherein the reduced C1s level is less than the C1s level of a normal or healthy subject.

80. The method of any one of claims 1 to 78, wherein the reduced C1s level is less than the C1s level of a normal or healthy subject of comparable age.

81. The method of any one of claims 77 to 80, wherein the decreased C1s level is less than a reference C1s level.

82. The method of claim 81, wherein the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from subjects with lupus nephritis.

83. The method of claim 81, wherein the reference C1s level is a value equal to or less than the mean or median of C1s levels in samples derived from age-matched lupus nephritis subjects.

84. The method of claim 81, wherein the reference C1s level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C1s levels in samples derived from subjects with lupus nephritis.

85. The method of claim 81, wherein the reference C1s level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C1s levels in samples from age-matched subjects with lupus nephritis.

86. The method of claim 81, wherein the reference C1s level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C1s levels in samples derived from normal or healthy subjects.

87. The method of claim 81, wherein the reference C1s level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C1s levels in samples derived from normal or healthy subjects of similar age.

88. The method of any one of claims 79 to 87, wherein the normal or healthy subject does not have lupus nephritis.

89. The method of any one of claims 81 to 88, wherein the decreased C1s level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% lower than the reference C4 level.

90. The method of any one of claims 81 to 88, wherein the decreased C1s level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% below the reference C4 level.

91. The method of claim 1, wherein the subject has elevated C2b levels.

92. The method of claim 91, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Elevated C1sC1 inhibitor levels; f. Reduced C1s levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

93. The method of any one of claims 1 to 92, wherein the elevated C2b level is greater than the C2b level of a normal or healthy subject.

94. The method of any one of claims 1 to 93, wherein the elevated C2b level is greater than the C2b level of a normal or healthy subject of comparable age.

95. The method of any one of claims 1 to 94, wherein the elevated C2b level is greater than a reference C2b level.

96. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the mean or median of C2b levels in samples derived from subjects with lupus nephritis.

97. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the mean or median of C2b levels in samples derived from age-matched lupus nephritis subjects.

98. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples derived from subjects with lupus nephritis.

99. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples from age-matched lupus nephritis subjects.

100. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples derived from normal or healthy subjects.

101. The method of claim 95, wherein the reference C2b level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C2b levels in samples derived from normal or healthy subjects of similar age.

102. The method of any one of claims 92 to 11, wherein the normal or healthy subject does not have lupus nephritis.

103. The method of any one of claims 95 to 102, wherein the elevated C2b level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C2b level.

104. The method of any one of claims 95 to 102, wherein the elevated C2b level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C2b level.

105. The method of claim 1, wherein the subject has an elevated C2b / C2 ratio.

106. The method of claim 105, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Elevated C1sC1 inhibitor levels; f. Reduced C1s levels; g. Reduced C2 levels; h. Elevated C2b levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

107. The method of any one of claims 1 to 106, wherein the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject.

108. The method of any one of claims 1 to 107, wherein the elevated C2b / C2 ratio is greater than the C2b / C2 ratio of a normal or healthy subject of comparable age.

109. The method of any one of claims 1 to 108, wherein the elevated C2b / C2 ratio is greater than a reference C2b / C2 ratio.

110. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the mean or median of C2b / C2 ratios in samples derived from subjects with lupus nephritis.

111. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the mean or median of C2b / C2 ratios in samples derived from age-matched lupus nephritis subjects.

112. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples derived from subjects with lupus nephritis.

113. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in samples from age-matched lupus nephritis subjects.

114. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in a sample derived from a normal or healthy subject.

115. The method of claim 109, wherein the reference C2b / C2 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C2b / C2 ratio in a sample derived from normal or healthy subjects of similar age.

116. The method of any one of claims 107 to 115, wherein the normal or healthy subject does not have lupus nephritis.

117. The method of any one of claims 109 to 116, wherein the elevated C2b / C2 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% higher than the reference C2b / C2 ratio.

118. The method of any one of claims 109 to 116, wherein the elevated C2b / C2 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C2b / C2 ratio.

119. The method of claim 1, wherein the subject has decreased C2 levels.

120. The method of claim 119, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Elevated C1sC1 inhibitor levels; f. Reduced C1s levels; g. Elevated C2b levels; h. Increased C2b / C2 ratio; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

121. The method of any one of claims 1 to 120, wherein the reduced C2 level is less than the C2 level of a normal or healthy subject.

122. The method of any one of claims 1 to 120, wherein the reduced C2 level is less than the C2 level of a normal or healthy subject of comparable age.

123. The method of any one of claims 1 to 122, wherein the decreased C2 level is less than a reference C2 level.

124. The method of claim 123, wherein the reference C2 level is a value equal to or less than the mean or median of C2 levels in samples derived from subjects with lupus nephritis.

125. The method of claim 123, wherein the reference C2 level is a value equal to or less than the mean or median of C2 levels in samples derived from age-matched lupus nephritis subjects.

126. The method of claim 123, wherein the reference C2 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C2 levels in samples derived from subjects with lupus nephritis.

127. The method of claim 123, wherein the reference C2 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from age-matched subjects with lupus nephritis.

128. The method of claim 123, wherein the reference C2 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in a sample derived from a normal or healthy subject.

129. The method of claim 123, wherein the reference C2 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C2 levels in samples from normal or healthy subjects of similar age.

130. The method of any one of claims 122 to 129, wherein the normal or healthy subject does not have lupus nephritis.

131. The method of any one of claims 123 to 130, wherein the decreased C2 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% lower than the reference C2 level.

132. The method of any one of claims 123 to 130, wherein the reduced C2 level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C2 level.

133. The method of claim 1, wherein the subject has elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3).

134. The method of claim 133, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Reduced C4 levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Elevated C1sC1 inhibitor levels; f. Reduced C1s levels; g. Elevated C2b levels; h. Increased C2b / C2 ratio; i. Reduced C2 levels; j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

135. The method of any one of claims 1 to 134, wherein the elevated PACA1 and / or PACA3 levels are greater than the PACA1 and / or PACA3 levels of a normal or healthy subject.

136. The method of any one of claims 1 to 134, wherein the elevated PACA1 and / or PACA3 levels are greater than the PACA1 and / or PACA3 levels of normal or healthy subjects of comparable age.

137. The method of any one of claims 1 to 136, wherein the elevated PACA1 and / or PACA3 level is greater than a reference PACA1 and / or PACA3 level.

138. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the mean or median of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis.

139. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the mean or median PACA1 and / or PACA3 levels in samples derived from age-matched lupus nephritis subjects.

140. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in samples derived from subjects with lupus nephritis.

141. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in samples from age-matched subjects with lupus nephritis.

142. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in a sample derived from a normal or healthy subject.

143. The method of claim 137, wherein the reference PACA1 and / or PACA3 level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of PACA1 and / or PACA3 levels in a sample derived from normal or healthy subjects of similar age.

144. The method of any one of claims 135 to 143, wherein the normal or healthy subject does not have lupus nephritis.

145. The method of any one of claims 137 to 144, wherein the elevated PACA1 and / or PACA3 levels are at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference PACA1 and / or PACA3 levels.

146. The method of any one of claims 137 to 144, wherein the elevated PACA1 and / or PACA3 levels are at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference PACA1 and / or PACA3 levels.

147. The method of claim 6, wherein the subject has elevated C3a levels.

148. The method of claim 147, wherein the subject has at least one of the following additional characteristics: a. Increased C4x / C4 ratio; b. Reduced C4 levels; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C4x levels; k. Elevated C3a / C3 ratio; or 1. Reduced C3 levels.

149. The method of any one of claims 6 to 148, wherein the elevated C3a level is greater than the C3a level of a normal or healthy subject.

150. The method of any one of claims 6 to 148, wherein the elevated C3a level is greater than the C3a level of a normal or healthy subject of comparable age.

151. The method of any one of claims 6 to 150, wherein the elevated C3a level is greater than a reference C3a level.

152. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from subjects with lupus nephritis.

153. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the mean or median of C3a levels in samples derived from age-matched lupus nephritis subjects.

154. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples derived from subjects with lupus nephritis.

155. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples from age-matched lupus nephritis subjects.

156. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in a sample derived from a normal or healthy subject.

157. The method of claim 151, wherein the reference C3a level is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of C3a levels in samples derived from normal or healthy subjects of similar age.

158. The method of any one of claims 149 to 157, wherein the normal or healthy subject does not have lupus nephritis.

159. The method of any one of claims 151 to 158, wherein the elevated C3a level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400%, or 500% higher than the reference C3a level.

160. The method of any one of claims 151 to 158, wherein the elevated C3a level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% higher than the reference C3a level.

161. The method of claim 6, wherein the subject has an elevated C3a / C3 ratio.

162. The method of claim 161, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Reduced C4 levels; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C4x / C4 ratio; or 1. Reduced C3 levels.

163. The method of any one of claims 6 to 162, wherein the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject.

164. The method of any one of claims 6 to 162, wherein the elevated C3a / C3 ratio is greater than the C3a / C3 ratio of a normal or healthy subject of comparable age.

165. The method of any one of claims 6 to 164, wherein the elevated C3a / C3 ratio is greater than a reference C3a / C3 ratio.

166. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the mean or median of C3a / C3 ratios in samples derived from subjects with lupus nephritis.

167. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the mean or median of C3a / C3 ratios in samples derived from age-matched lupus nephritis subjects.

168. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in samples derived from subjects with lupus nephritis.

169. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in samples from age-matched lupus nephritis subjects.

170. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th, or 100th percentile of the C3a / C3 ratio in a sample derived from a normal or healthy subject.

171. The method of claim 165, wherein the reference C3a / C3 ratio is a value equal to or greater than the 50th, 55th, 60th, 65th, 70th, 75th, 80th, 85th, 90th, 95th or 100th percentile of the C3a / C3 ratio in a sample derived from normal or healthy subjects of similar age.

172. The method of any one of claims 163 to 171, wherein the normal or healthy subject does not have lupus nephritis.

173. The method of any one of claims 165 to 172, wherein the elevated C3a / C3 ratio is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% higher than the reference C3a / C3 ratio.

174. The method of any one of claims 165 to 172, wherein the elevated C3a / C3 ratio is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400% or 400%-500% higher than the reference C3a / C3 ratio.

175. The method of claim 6, wherein the subject has decreased C3 levels.

176. The method of claim 175, wherein the subject has at least one of the following additional characteristics: a. Elevated C4x levels; b. Increased C4x / C4 ratio; c. Elevated C1sC1 inhibitor levels; d. Increased C1sC1 inhibitor / C1s ratio; e. Reduced C1s levels; f. Elevated C2b levels; g. Increased C2b / C2 ratio; h. Reduced C2 levels; i. Elevated levels of pathogenic anti-C1q antibody 1 (PACA1) and / or pathogenic anti-C1q antibody 3 (PACA3); j. Elevated C3a levels; k. Elevated C3a / C3 ratio; or 1. Reduced C4 levels.

177. The method of any one of claims 6 to 176, wherein the reduced C3 level is less than the C3 level of a normal or healthy subject.

178. The method of any one of claims 6 to 176, wherein the reduced C3 level is less than the C3 level of a normal or healthy subject of comparable age.

179. The method of any one of claims 177 to 178, wherein the decreased C3 level is less than a reference C3 level.

180. The method of claim 179, wherein the reference C3 level is a value equal to or less than the mean or median of C3 levels in samples derived from subjects with lupus nephritis.

181. The method of claim 179, wherein the reference C3 level is a value equal to or less than the mean or median of C3 levels in samples derived from age-matched lupus nephritis subjects.

182. The method of claim 179, wherein the reference C3 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile, or 0th percentile of C3 levels in samples derived from subjects with lupus nephritis.

183. The method of claim 179, wherein the reference C3 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C3 levels in samples from age-matched lupus nephritis subjects.

184. The method of claim 179, wherein the reference C3 level is a value equal to or less than the 55th percentile, 50th percentile, 45th percentile, 40th percentile, 35th percentile, 30th percentile, 25th percentile, 20th percentile, 15th percentile, 10th percentile, 5th percentile or 0th percentile of C3 levels in a sample derived from a normal or healthy subject.

185. The method of claim 179, wherein the reference C3 level is a value equal to or less than the 55th, 50th, 45th, 40th, 35th, 30th, 25th, 20th, 15th, 10th, 5th, or 0th percentile of C3 levels in samples from normal or healthy subjects of similar age.

186. The method of any one of claims 177 to 175, wherein the normal or healthy subject does not have lupus nephritis.

187. The method of any one of claims 179 to 186, wherein the decreased C3 level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 200%, 300%, 400% or 500% lower than the reference C4 level.

188. The method of any one of claims 179 to 186, wherein the decreased C3 level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 200%-300%, 300%-400%, or 400%-500% lower than the reference C4 level.

189. The method of any one of claims 1 to 188, wherein the C4x level, or the C4x / C4 ratio, or the C4 level, or the C1sC1 inhibitor level, or the C1sC1 inhibitor / C1s ratio, or the C1s level, or the C2b level, or the C2b / C2 ratio, or the C2 level, or the PACA1 and / or PACA3 level, or the C3a level, or the C3a / C3 ratio, or the C3 level is measured in plasma or urine.

190. The method of any one of claims 1 to 189, wherein the subject has elevated urine protein / creatinine ratio (UPCR) levels.

191. The method of claim 190, wherein the elevated UPCR level is greater than the UPCR level of a normal or healthy subject.

192. The method of claim 190, wherein the elevated UPCR level is greater than the UPCR level of a normal or healthy subject of comparable age.

193. The method of any one of claims 190 to 192, wherein the elevated uPCR level is greater than a reference uPCR level.

194. The method of claim 193, wherein the reference uPCR level is equal to or greater than about 0.5 g / g, 1.0 g / g, 1.5 g / g, 2.0 g / g, 2.5 g / g, 3.0 g / g, 3.5 g / g, 4.0 g / g, 4.5 g / g, or 5.0 g / g.

195. The method of any one of claims 192 to 194, wherein the elevated uPCR level is at least 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, 106%, 107%, 108%, 109%, 110%, 111%, 112%, 113%, 114%, 115%, 116%, 117%, 118%, 119%, 120%, 121%, 122%, 123%, 124%, 125%, 126%, 127%, 128%, 129%, 200%, 201 %, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1000%, 2000%, 3000%, 4000% or 5000%.

196. The method of any one of claims 192 to 194, wherein the elevated UPCR level is at least 1%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 100%-200%, 100%-300%, 100%-400%, 100%-500%, 100%-600%, 100%-700%, 100%-800%, 100%-900%, 100%-1000%, 100%-1000%, 100%-1000%, 100%-2000%, 100%-3000%, 100%-4000%, 100%-5000%, 100%-6000%, 100%-7000%, 100%-8000%, 100%-9000%, 100%-10000%, 100%- %-100%, 100%-200%, 200%-300%, 300%-400%, 400%-500%, 500%-600%, 600%-700%, 700%-800%, 800%-900%, 900%-1000%, 1000%-2000%, 2000%-3000%, 3000%-4000% or 4000-5000%.

197. The method of any one of claims 191 to 196, wherein the uPCR level is measured in urine.

198. The method of any one of claims 1 to 197, wherein the classical complement inhibitor is a C1 inhibitor.

199. The method of claim 198, wherein the C1 inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

200. The method of any one of claims 1 to 197, wherein the inhibitor of the classical complement pathway is a CIq inhibitor.

201. The method of claim 200, wherein the CIq inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

202. The method of claim 201, wherein the antibody is an anti-C1q antibody.

203. The method of claim 202, wherein the antibody is a monoclonal antibody, a polyclonal antibody, a recombinant antibody, a humanized antibody, a chimeric antibody, a multispecific antibody, or an antibody derivative thereof.

204. The method of claim 202, wherein said antibody derivatives thereof are one-armed antibodies.

205. The method of claim 203 or 204, wherein the antibody is administered at a dose of at least 50 mg / kg.

206. The method of claim 203 or 204, wherein the antibody is administered at a dose between 50 mg / kg and 200 mg / kg.

207. The method of claim 203 or 204, wherein the antibody is administered at a dose of 50 mg / kg, 55 mg / kg, 60 mg / kg, 65 mg / kg, 70 mg / kg, 75 mg / kg, 80 mg / kg, 85 mg / kg, 90 mg / kg, 95 mg / kg, 100 mg / kg, 105 mg / kg, 110 mg / kg, 115 mg / kg, 120 mg / kg, 125 mg / kg, 130 mg / kg, 135 mg / kg, 140 mg / kg, 145 mg / kg, 150 mg / kg, 155 mg / kg, 160 mg / kg, 165 mg / kg, 170 mg / kg, 175 mg / kg, 180 mg / kg, 185 mg / kg, 190 mg / kg, 195 mg / kg, or 200 mg / kg.

208. The method of any one of claims 203 to 207, wherein the antibody is administered in a total amount of at least 50 mg.

209. The method of any one of claims 203 to 207, wherein the antibody is administered at a total dose of 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 105 mg, 110 mg, 115 mg, 120 mg, 125 mg, 130 mg, 135 mg, 140 mg, 145 mg, 150 mg, 155 mg, 160 mg, 165 mg, 170 mg, 175 mg, 180 mg, 185 mg, 190 mg, 195 mg, or 200 mg.

210. The method of any one of claims 207 to 209, wherein the antibody is administered daily.

211. The method of any one of claims 207 to 209, wherein the antibody is administered once a week.

212. The method of any one of claims 207 to 209, wherein the antibody is administered every other week.

213. The method of any one of claims 207 to 209, wherein the antibody is administered monthly.

214. The method of any one of claims 207 to 209, wherein the antibody is administered once every six weeks.

215. The method of any one of claims 207 to 209, wherein the antibody is administered every other month.

216. The method of any one of claims 207 to 209, wherein the antibody is administered for at least 3 months, 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months.

217. The method of claim 216, wherein the antibody is administered for 6 months.

218. The method of any one of claims 207 to 209, wherein the antibody is administered throughout the patient's lifetime, or intermittently during the patient's lifetime in response to fever.

219. The method of claim 203 or 204, wherein the antibody is administered at a dose of 75 mg / kg on day 1 and on day 5 or day 6.

220. The method of claim 219, wherein the antibody is further administered at a dose of 100 mg / kg every two weeks.

221. The method of any one of claims 203 to 220, wherein the antibody is administered intravenously.

222. The method of claim 202, wherein the antibody is an antibody fragment.

223. The method of claim 221, wherein the antibody fragment is a Fab fragment, a Fab' fragment, a F(ab')2 fragment, a Fv fragment, a diabody, or a single-chain antibody molecule.

224. The method of claim 222 or 223, wherein the antibody fragment is administered at a total dose of at least 250 mg.

225. The method of claim 222 or 223, wherein the antibody fragment is administered at a total dose of between 250 mg and 1000 mg.

226. The method of any one of claims 222 to 225, wherein the antibody fragment is administered at 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, 500 mg, 525 mg, 550 mg, 575 mg, 600 mg, 625 mg, 650 mg, 675 mg, 700 mg, 725 mg, 750 mg, 775 mg g, 800mg, 825mg, 850mg, 875mg, 900mg, 925mg, 950mg, 975mg, 1000mg, 1250mg, 1275mg, 1300mg, 1325m g, 1350mg, 1375mg, 1400mg, 1425mg, 1450mg, 1475mg, 1500mg, 1525mg, 1550mg, 1575mg, 1600mg, 1625 mg, 1650mg, 1675mg, 1700mg, 1725mg, 1750mg, 1775mg, 1800mg, 1825mg, 1850mg, 1875mg, 1900mg, 19 25mg, 1950mg, 1975mg, 2000mg, 2250mg, 2275mg, 2300mg, 2325mg, 2350mg, 2375mg, 2400mg, 2425mg, 2 or 3000 mg in a total dose of 450 mg, 2475 mg, 2500 mg, 2525 mg, 2550 mg, 2575 mg, 2600 mg, 2625 mg, 2650 mg, 2675 mg, 2700 mg, 2725 mg, 2750 mg, 2775 mg, 2800 mg, 2825 mg, 2850 mg, 2875 mg, 2900 mg, 2925 mg, 2950 mg, 2975 mg, or 3000 mg.

227. The method of any one of claims 222 to 226, wherein the antibody fragment is administered daily.

228. The method of any one of claims 222 to 226, wherein the antibody fragment is administered every other day.

229. The method of any one of claims 222 to 226, wherein the antibody fragment is administered once every three days, once every four days, once every five days, or once every six days.

230. The method of any one of claims 222 to 226, wherein the antibody fragment is administered once a week.

231. The method of any one of claims 222 to 226, wherein the antibody fragment is administered once every two weeks.

232. The method of any one of claims 222 to 226, wherein the antibody fragment is administered once a month.

233. The method of any one of claims 222 to 226, wherein the antibody fragment is administered for at least 3 months, 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, or at least 12 months.

234. The method of any one of claims 222 to 226, wherein the antibody fragment is administered throughout the patient's lifetime, or intermittently during the patient's lifetime during times of fever.

235. The method of any one of claims 298 to 234, wherein the antibody fragment is administered subcutaneously.

236. The method of any one of claims 198 to 235, wherein the anti-C1q antibody inhibits the interaction between C1q and an autoantibody or between C1q and C1r or between C1q and C1s.

237. The method of any one of claims 202 to 235, wherein the anti-C1q antibody promotes clearance of C1q from circulation or tissues.

238. The method of any one of claims 202-237, wherein the antibody comprises a light chain variable domain comprising an HVR-L1 having an amino acid sequence of SEQ ID NO:5, an HVR-L2 having an amino acid sequence of SEQ ID NO:6, and an HVR-L3 having an amino acid sequence of SEQ ID NO:

7.

239. The method of any one of claims 202-238, wherein the antibody comprises a heavy chain variable domain comprising an HVR-H1 having an amino acid sequence of SEQ ID NO:9, an HVR-H2 having an amino acid sequence of SEQ ID NO:10, and an HVR-H3 having an amino acid sequence of SEQ ID NO:

11.

240. The method of any one of claims 202 to 239, wherein the antibody comprises a light chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NOs:4 and 35-38, and wherein the light chain variable domain comprises an HVR-L1 having an amino acid sequence of SEQ ID NO:5, an HVR-L2 having amino acids of SEQ ID NO:6, and an HVR-L3 having amino acids of SEQ ID NO:

7.

241. The method of claim 240, wherein the light chain variable domain comprises an amino acid sequence selected from SEQ ID NOs: 4 and 35-38.

242. The method of any one of claims 202-241, wherein the antibody comprises a heavy chain variable domain comprising an amino acid sequence having at least about 95% homology to an amino acid sequence selected from SEQ ID NOs: 8 and 31-34, and wherein the heavy chain variable domain comprises an HVR-H1 having an amino acid sequence of SEQ ID NO: 9, an HVR-H2 having amino acids of SEQ ID NO: 10, and an HVR-H3 having amino acids of SEQ ID NO:

11.

243. The method of claim 242, wherein the heavy chain variable domain comprises an amino acid sequence selected from SEQ ID NOs: 8 and 31 to 34.

244. The method of any one of claims 198-243, wherein the antibody fragment comprises a heavy chain Fab fragment of SEQ ID NO:39 and a light chain Fab fragment of SEQ ID NO:

40.

245. The method of any one of claims 1-197, wherein the inhibitor of the classical complement pathway is a C1r inhibitor.

246. The method of claim 245, wherein the C1r inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

247. The method of claim 246, wherein the antibody is an anti-C1r antibody.

248. The method of claim 247, wherein the anti-C1r antibody inhibits the interaction between C1r and C1q or between C1r and C1s, or wherein the anti-C1r antibody inhibits the catalytic activity of C1r, or inhibits the processing of pro-C1r into an active protease.

249. The method of any one of claims 1-197, wherein the inhibitor of the classical complement pathway is a C1s inhibitor.

250. The method of claim 249, wherein the C1s inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

251. The method of claim 250, wherein the antibody is an anti-C1s antibody.

252. The method of claim 251, wherein the anti-C1s antibody inhibits the interaction between C1s and C1q, or between C1s and C1r, or between C1s and C2 or C4, or wherein the anti-C1s antibody inhibits the catalytic activity of C1s, or inhibits the processing of pro-C1s into an active protease, or binds to an activated form of C1s.

253. The method of claim 251, wherein the antibody is sutelimumab.

254. The method of any one of claims 1 to 197, wherein the inhibitor of the classical complement pathway is an anti-C1 complex antibody, optionally wherein the anti-C1 complex antibody inhibits activation of C1r or C1s or blocks their ability to act on C2 or C4.

255. The method of claim 254, wherein the anti-C1 complex antibody binds to a combined epitope within the C1 complex, wherein the combined epitope comprises amino acids of both C1q and C1s; amino acids of both C1q and C1r; amino acids of both C1r and C1s; or amino acids of each of C1q, C1r, and C1s.

256. The method of any one of claims 1-197, wherein the inhibitor of the classical complement pathway is a C2 inhibitor.

257. The method of claim 256, wherein the C2 inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

258. The method of any one of claims 1-197, wherein the inhibitor of the classical complement pathway is a C3 inhibitor.

259. The method of claim 258, wherein the C3 inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

260. The method of claim 259, wherein the C3 inhibitor is APL-9 (Apellis) or AMY-101 (Amyndas).

261. The method of any one of claims 1-197, wherein the inhibitor of the classical complement pathway is a C4 inhibitor.

262. The method of claim 261, wherein the C4 inhibitor is a small molecule, an antibody, an aptamer, an antisense nucleic acid, or a gene editing agent.

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