Diagnostic drugs for autoimmune diseases

Abstract

A diagnostic drug and a diagnostic kit for autoimmune diseases including at least one of a polypeptide selected from an HMG-1 family, a polypeptide selected from an HMG-2 family, a fragment thereof which is reactable with an antibody of an autoimmune disease patient, and a method for detecting an antibody of an autoimmune disease patient using the same are provided.

Description

[0001] The present invention relates to a diagnostic drug for and a kit for diagnosing autoimmune diseases, and a method for detecting an antibody of an autoimmune disease patient using high mobility group protein-1 (HMG-1), high mobility group protein-2 (HMG-2), or a fragment of a polypeptide thereof with which the antibody of the autoimmune disease patient reacts. In particular, the present invention relates to a diagnostic drug for and a kit for diagnosing rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Behet's disease, scleroderma, primary biliary cirrhosis, microscopic polyangiitis / polyarteritis nodosa, ulcerative colitis, Crohn's disease, and autoimmune hepatitis, and a method for detecting an antibody of a patient of any of the above-mentioned diseases, using HMG-1, HMG-2, or a fragment of a polypeptide thereof with which the antibody of such a patient reacts.[0002] It has been reported that various anti-neutrophil cytoplasmic antibodies (ANCA) are inv...

AI Technical Summary

Benefits of technology

[0011] As a result of active studies in order to overcome the above-described problems with the prior art, the present inventors succeeded for the first time in history in isolating high mobility group protein-1 (HMG-1) and high mobility group protein-2 (HMG-2), which are known proteins, using antibodies in the sera of the autoimmune disease patients, especially pANCA-positive ulcerative colitis patients. HMG-1 and HMG-2 were isolated and identified as novel antigens with which the antibodies react (Sobajima J. et al., Clin. Exp. Immunol. 105:120-124, 1996; Sobajima J. et al., Clin. Exp. Immunol. 107:135-140, 1997). By constructing an ELISA system using the HMG-1 and HMG-2, the present inventors showed that a high percentage of antibodies of the patients of rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Behet's disease, scleroderma, primary biliary cirrhosis, microscopic polyangiitis / polyarteritis nodosa, ulcerative colitis, Crohn's disease and autoimmune hepatitis are positive to these antigens. By showing that the ELISA system is more sensitive, simpler, more reliable and more objective than measurement for antinuclear antibodies by indirect immunofluorescence assay, the present inventors found that antibodies against the antigens can be markers for diagnosis of rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Behet's disease, scleroderma, primary biliary cirrhosis, microscopic polyangiitis / polyarteritis nodosa, ulcerative colitis, Crohn's disease and autoimmune hepatitis. Thus, the present invention has been completed.

[0047] Scleroderma (systemic sclerosis) is a connective-tissue disease accompanying sclerosis of skin and organ disorders. It includes various types and is not necessary systemic or progressive. It accompanies sclerosis of skin in a large part of the entire body (generalized scleroderma) and organ disorders of esophagus, intestines, lung, liver and thyroid gland or the like. There are various types including a highly progressive type having unfavorable prognosis and a type referred to as CREST syndrome having favorable prognosis. In the case of the CREST syndrome, the skin sclerosis is limited to face, hands and fingers and the viscus lesion appears gradually. Among the antinuclear antibodies, anti-Sc1-70 antibody, which is an antibody to topoisomerase-1, is highly specific to a generalized type of scleroderma (percentage of positive patients: 30%). An anti-centromere antibody has a high diagnostic value to the CREST syndrome. An anti-Ku antibody has a high diagnostic value to duplicated syndrome of scleroderma and polymyositis.

[0079] Patients of various autoimmune diseases, i.e., rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Behet's disease, scleroderma, polymyositis / dermatomyositis, primary biliary cirrhosis, microscopic polyangiitis / polyarteritis nodosa, ulcerative colitis, Crohn's disease, autoimmune hepatitis (AIH), hepatitis C and hepatitis B, and healthy persons were measured for an anti-HMG-1 antibody and an anti-HMG-2 antibody. As a result, HMG-1 had a higher antigenicity and more patients were anti-HGM-1 antibody positive compared to HMG-2 among the patients of seven diseases other than primary biliary cirrhosis, ulcerative colitis, Behet's disease, AIH, hepatitis B and hepatitis C. Regarding HMG-1, the patients of 11 diseases other than polymyositis / dermatomyositis and hepatitis B, a statistically significant difference from the healthy persons was shown. As a result of comparison with a percentage of antinuclear antibody-positive patients obtained by indirect immunofluorescence assay, the percentage of the anti-HMG antibody-positive patients were equal to or higher than the percentage of the antinuclear antibody-positive patients among eight out of the 13 diseases. This indicates the possibility that measurement of an anti-HMG-1 antibody and an anti-HMG-2 antibody can be a diagnostic method for autoimmune diseases replacing detection of an antinuclear antibody by indirect immunofluorescence assay. When used with the detection of antinuclear antibody, the measurement of an anti-HMG-1 antibody and an anti-HMG-2 antibody can diagnose a wider range of autoimmune diseases more accurately.

Problems solved by technology

These methods are costly, painful, and time-consuming.

However, this method is not sufficiently sensitive and tends to have an increased background signal.

Serodiagnosis, by which neutrophils and other cells are fixed on a plate with ethanol, has a further disadvantage in that the result depends on the state of the cells and the fixing technique and is not sufficiently reliable.

However, a simple serodiagnostic method has not been developed.

However, it has been pointed out that there are many problems in uniformalizing the measurement precision of antinuclear antibodies.

The problems include, for example, that the nucleus materials (cells) vary in accordance with the research facilities, the calibration curve cannot be obtained, and the autoantibodies are non-uniform.

The most serious problem is that the method relies on visual observation and thus the determination criterion and technology are not objective.

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