Antimicrobial peptides

Abstract

Disclosed herein are methods of diagnosing, selecting, monitoring, and treating subjects with Alzheimer's disease (AD) or suspected of having AD, based on presence of antimicrobial peptides (AMPs) at levels that differ from those in control individuals.

Description

[0001] Attorney Docket Number 08061.0063-00304 ANTIMICROBIAL PEPTIDES RELATED APPLICATION This application claims the benefit of and priority to US Provisional Application Serial No.63 / 513,868, filed July 15, 2023, the contents of which are incorporated herein by reference in their entirety. FIELD Described herein are methods for treating Alzheimer’s disease (AD) in a subject, relating to measurements of the antimicrobial peptides (AMPs) in biofluid samples from a subject. Levels of these select AMPs may be used for different aspects of treating AD, such as selecting a subject for treatment, treating AD and symptoms associated with AD, monitoring and / or adjusting the treatment, and determining maintenance dosing regimens for subjects. BACKGROUND Alzheimer’s disease (AD) is a progressive, neurodegenerative disorder of uncertain etiology and the most common form of dementia among older people. In 2006, there were 26.6 million cases of AD in the world (range: 11.4-59.4 million) (Brookmeyer, R., et al., Forecasting the global burden of Alzheimer’s Disease. Alzheimer Dement.2007; 3:186-91), while there were more than 5 million people in the United States reportedly living with AD (Alzheimer’s Association, Alzheimer’s Association report, 2010 Alzheimer’s disease facts and figures. Alzheimer Dement.2010;6:158-94). By the year 2050, the worldwide prevalence of AD is predicted to grow to 106.8 million (range: 47.2-221.2 million), while in the United States alone the prevalence is estimated to be 11 to 16 million. (Brookmeyer, supra, and 2010 Alzheimer’s disease facts and figures, supra). The disease generally involves a global decline of cognitive function that progresses slowly and leaves end-stage subjects bedridden. AD subjects typically survive for only 3 to 10 years after symptom onset, although extremes of 2 and 20 years are known. (Hebert, L.E., et al., Alzheimer disease in the U.S. population: prevalence estimates using the 2000 census. Arch Neurol.2003; 60:1119-1122.) AD is the seventh leading cause of all deaths in the United States and the fifth leading cause of death in Americans older than the age of 65 years, despite the fact that mortality due to AD is greatly underestimated because death certificates rarely attribute the cause of death to AD. (Alzheimer’s Association. Attorney Docket Number 08061.0063-00304 Alzheimer’s Association report. 2010 Alzheimer’s disease facts and figures. Alzheimer Dement.2010; 6:158-94.) AD represents a significant economic burden across industrialized countries with a substantial impact on healthcare systems and the public purse as well as on subjects and their families. In the United States alone, total payments for 2010 were estimated at $172 billion, including $123 billion for Medicare and Medicaid. Histologically, the disease is characterized by neuritic plaques, found primarily in the association cortex, limbic system and basal ganglia. The major constituent of these plaques is amyloid beta peptide (Aβ). Aβ exists in various conformational states - monomers, oligomers, protofibrils, and insoluble fibrils. Details of the mechanistic relationship between onset of Alzheimer’s disease and Aβ production is unknown. However, some anti-Aβ antibodies are undergoing clinical study now as potential therapeutic agents for Alzheimer’s disease. Despite the recent development of treatments for AD, including those targeting Aβ, there remains a need for improved diagnosis of AD and better monitoring of treatments, including more specific markers which may be used to diagnose AD in subjects, predict disease prognosis, monitor progression of the disease, and indicate efficacy of treatment. It remains challenging to select relevant, robust markers from the numerous biomolecules involved in AD. Recently, studies suggest that antimicrobial peptides may be used as biomarkers for diagnosing AD (Bruno et al., Antibiotics, 2022, 11:6, 726). Antimicrobial peptides (AMPs) are small (12-50 amino acid), charged, cationic, usually amphipathic peptides that provide the first line of defense against bacteria, fungi, parasites, and viruses by oligomerizing into a “nanonet” of fibrils that trap an invading pathogen. AMPs are expressed at high levels in brain and other immune-privileged organs where the activities of adaptive immunity are constrained. The majority of AMPs are synthesized as large polyprotein precursors and proteolytic processing releases small (12-50 amino acid) active peptide segments. Removal of signal peptide may be a post-translation, or a co-translational process and traditional DNA and RNA sequencing based approaches may not be suitable to study AMP peptides. One pathological hallmark of AD is activation of the innate immune system. Accumulating evidence suggests that A ^ is an effector molecule of the innate immune system and also serve an antimicrobial peptide whose oligomerization mediates pathogen Attorney Docket Number 08061.0063-00304 entrapments to protect against infection the “Antimicrobial Protection Hypothesis of AD” (Moir et al., Alzheimer’s & Dementia.2018;14: 1602-1614). Aβ1-42bears convincing structural similarities with viral fusion domains and AMPs, and sequence similarities with a specific family of bacterial bacteriocins. This has opened the door for new studies identifying novel AMPs with the ability to influence neurological disorders. AMPs are also activated by inflammation. The “infection hypothesis” of AD proposes that weakening of the blood-brain barrier (BBB) and the immune system in aging subjects, in combination with infections from microorganisms, leads to chronic neuroinflammation. While no specific pathogen has been identified as causing AD, coexistence of pathogens in the brain of subjects with AD and a role for Aβ as an antimicrobial peptide suggests that chronic neuroinflammation may contribute to the pathogenesis (Vigasova et al., Microbial Cell Factories, 2021; 20: 25). In an inflamed state, the production of Aβ and phosphorylated-tau is increased, which could lead to aggregation of these proteins into tangles and plaques and subsequent neurodegeneration. Consistent with the infection hypothesis, antimicrobial peptides (AMPs) may mediate processes of aggregation and / or neurodegeneration. Certain AMPs such as lactoferrin and cystatins interact with Aβ and are found in amyloid plaques. In addition, lactoferrin, cystatin, and other AMPs show increased expression in saliva, blood, serum, and / or CSF obtained from AD patients (Bruno et al., Antibiotics, 2022, 11, 726). While this data is promising, there remains a need for further analysis of the diagnostic potential of AMPs overall, and for identification of highly-specific AMPs that may be used for diagnosis of AD. Disclosed herein are improved methods of diagnosing, monitoring, and treating patients with AD based on determining levels of AMPs that show strong differential expression in subjects with AD as compared with control individuals. SUMMARY One aspect of the present disclosure relates to a method of selecting a subject for a treatment with an Alzheimer’s disease (AD) therapy, comprising: a) obtaining a measurement of a level of at least one antimicrobial peptide (AMP) in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) selecting the subject for treatment if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). Attorney Docket Number 08061.0063-00304 An aspect of the present disclosure relates to a method of selecting a subject for a treatment with an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin- 40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) selecting the subject for treatment if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). In some embodiments, wherein the subject has early AD or mild to moderate AD. In some embodiments, the subject is selected for treatment if the AMP level from the subject is increased as compared to the control. In some embodiments, the subject is selected for treatment if the AMP level from the subject is decreased as compared to the control. A further aspect of the present disclosure relates to a method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level as compared to first AMP level is an indicator of treatment efficacy, optionally wherein the AD therapy is an anti- Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). A further aspect of the present disclosure relates to a method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Attorney Docket Number 08061.0063-00304 Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin- 40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level as compared to first AMP level is an indicator of treatment efficacy, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, a decrease in the second AMP level as compared to first AMP level indicates an effective treatment. In some embodiments, a lack of a decrease in the second AMP level as compared to first AMP level indicates a non-effective treatment. In some embodiments, a decrease in the second AMP level as compared to first AMP level indicates a non-effective treatment. In some embodiments,a lack of a decrease in the second AMP level as compared to first AMP level indicates an effective treatment. An aspect of the present disclosure relates to a method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) comparing the level of at least one AMP to a control sample, e.g., an AMP level concentration in an individual who does not have Alzheimer’s disease (AD); and c) adjusting the treatment regimen if the level of at least one AMP is different compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), e.g., by changing the size of the dose, the frequency of administration, and / or the route of administration of the anti-Aβ protofibril antibody, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). An aspect of the present disclosure relates to a method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin- ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) comparing the level of at least one Attorney Docket Number 08061.0063-00304 AMP to a control sample, e.g., an AMP level concentration in an individual who does not have Alzheimer’s disease (AD); and c) adjusting the treatment regimen if the level of at least one AMP is different compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), e.g., by changing the size of the dose, the frequency of administration, and / or the route of administration of the anti-Aβ protofibril antibody, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, the treatment regimen is adjusted if the AMP level is higher than a control. In some embodiments, the treatment regimen is adjusted if the AMP level is lower than a control. An aspect of the present disclosure relates to a method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab). An aspect of the present disclosure relates to a method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin- 40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody. Attorney Docket Number 08061.0063-00304 In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, a decreased AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject. In some embodiments, an increased AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject. An aspect of the present disclosure relates to a method of detecting a decrease in a brain tau level (e.g., a reduction in tau tangles) in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). An aspect of the present disclosure relates to a method of detecting a decrease in a brain tau level (e.g., a reduction in tau tangles) in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, a decreased AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject. In some embodiments, an Attorney Docket Number 08061.0063-00304 increased AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject. In some embodiments, a decrease of a brain tau level is a decrease in tau tangles. An aspect of the present disclosure relates to a method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the a first AMP level is elevated compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles, optionally wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3). An aspect of the present disclosure relates to a method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the first AMP level is elevated compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles, optionally wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions Attorney Docket Number 08061.0063-00304 (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3). An aspect of the present disclosure relates to a method of treating a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). An aspect of the present disclosure relates to a method of treating a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, the AD therapy is administered if the AMP level is increased compared to the control sample. In some embodiments, the AD therapy is administered if the AMP level is decreased compared to the control sample. In some embodiments, the method of treating a subject comprises, after steps a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject; and b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau antibody if the level of at least one AMP is elevated compared to a control sample, applying further steps of c) obtaining a further measurement of the level of at least one AMP (e.g., a further AMP level) in a second biofluid sample, e.g., a CSF or blood sample, from the subject; d) determining that the Attorney Docket Number 08061.0063-00304 further AMP level has changed relative to the level of at least one AMP obtained prior to administration of the AD therapy; and e) administering a further therapeutically effective dose of the AD therapy to the subject, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814). In some embodiments, the further therapeutically effective dose is administered according to a maintenance dosing regimen. In some embodiments, the treatment comprises administration of a therapeutically effective dose of the AD therapy according to an initiation dosing regimen, optionally after which the subject is switched to a maintenance dosing regimen. In some embodiments, the subject is switched from an initiation dosing regimen to a maintenance dosing regimen when a further measurement of AMP level in a further biofluid sample, e.g., a CSF or blood sample, from the subject differs from a threshold, e.g., a level seen in a control sample from an individual who does not have AD. In some embodiments, the subject is switched when the AMP level is below the threshold. In some embodiments, the subject is switched when the AMP level is above the threshold. In some embodiments, the AMP level is quantified by LC / MS. In some embodiments, the biofluid sample is CSF. In some embodiments, the subject shows a change and / or difference in a measurement of one or more additional biomarkers associated with AD pathology prior to treatment. In some embodiments, the change and / or difference in the measurement is selected from: a) increased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), b) increased tau in the brain, e.g., as measured by positron emission tomography (PET), c) decreased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and d) decreased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL). Attorney Docket Number 08061.0063-00304 In some embodiments, the subject shows a change and / or difference in a measurement of one or more additional biomarkers associated with AD pathology during and / or after treatment. In some embodiments, the change and / or difference in the measurement is selected from: a) decreased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), b) decreased tau in the brain, e.g., as measured by positron emission tomography (PET), c) increased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and d) increased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL). In some embodiments, the treatment a) delays clinical decline as determined by ADCOMS; b) delays clinical decline as determined by ADAS MCI-ADL; c) delays clinical decline as determined by modified iADRS; d) delays clinical decline as measured by a CDR- SB; or e) delays clinical decline as measured by an ADAS-Cog. In some embodiments, the subject has a genetic mutation for a dominantly inherited Alzheimer’s disease, e.g., wherein the subject a genetic mutation in at least one of three genes — PSEN1, PSEN2, or APP. In some embodiments, the subject has a mutation in APP. In some embodiments, the subject has a family history of Alzheimer’s disease, e.g., a history of a family member being diagnosed with Alzheimer’s disease before the age of 60. In some embodiments, the subject is ApoE4-positive. In some embodiments, the subject is 65 to 80 years old. In some embodiments, the subject is 55 to 64 years old and has at least one risk factor chosen from: (i) a first degree relative diagnosed with dementia onset before age 75; (ii) at least one apolipoprotein E4 variant (APOE4) allele; and (iii) elevated brain amyloid according to PET or cerebrospinal fluid (CSF) testing prior to said administration. In some embodiments, the subject is amyloid positive. Attorney Docket Number 08061.0063-00304 In some embodiments, the subject is amyloid positive based on a PET assessment, a CSF assessment of Aβ(1-42), a CSF assessment of total tau, a CSF assessment of phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, MRI, retinal amyloid accumulation, and / or a blood biomarker assessment (e.g. a plasma Aβ1-42 / 1-40 ratio, total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231) and / or MTBR-tau243. In some embodiments, the subject has Alzheimer’s disease. In some embodiments, the subject has early Alzheimer’s disease. In some embodiments, the subject has been diagnosed with a) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood and / or has been diagnosed as having mild Alzheimer’s disease dementia; b) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by National Institute of Aging – Alzheimer’s Association (NIA-AA) core clinical criteria; c) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by a CDR global score of 0.5 and a Memory Box score of 0.5 or greater before treatment; d) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by a history of subjective memory decline with gradual onset and slow progression over the last 1 year before treatment, e.g., as corroborated by an informant; e) mild Alzheimer’s disease dementia by the NIA-AA core clinical criteria for probable Alzheimer’s disease dementia; or f) mild Alzheimer’s disease dementia by a CDR score of 0.5 to 1.0 and a Memory Box score of 0.5 or greater before treatment. In some embodiments, the subject is suspected of having AD. In some embodiments, the subject is a subject at risk for developing AD. In some embodiments, the subject at risk for developing AD has pre-Alzheimer’s disease (pre-AD). In some embodiments, the subject does not have cognitive impairment. In some embodiments, the anti-Aβ protofibril antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 2 (HCDR2), and SEQ ID NO: 3 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 4 (LCDR1), SEQ ID NO: 5 (LCDR2), and SEQ ID NO: 6 (LCDR3). Attorney Docket Number 08061.0063-00304 In some embodiments, the anti-Aβ protofibril antibody is lecanemab. In some embodiments, the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3). In some embodiments, the anti-tau antibody is E2814. In some embodiments, the antimicrobial peptide comprises any one of SEQ ID NOs: 27-50. Enumerated Embodiments 1. A method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising: determining an altered level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10, and administering to the subject a therapeutically effective dose of an AD therapy, e.g., an anti- amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. 2. A method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising: determining an altered level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-ribosomal protein eS31 fusion protein (RS27A), Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC), and administering to the subject a therapeutically effective dose of an AD therapy, e.g., an anti- amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. Attorney Docket Number 08061.0063-00304 3. The method of embodiment 2, wherein the antimicrobial peptide is a peptide listed in Table 10. 4. The method of any one of embodiments 1-3, wherein the antimicrobial peptide comprises any one of SEQ ID NOs: 13-36. 5. The method of embodiment 1, wherein the subject is cognitively impaired. 6. The method of embodiment 1, wherein the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1- 42 / Aβ1-40 ratio in CSF that is below 0.065. 7. The method of embodiment 1, wherein the control is the level of AMP in a biofluid (e.g., CSF) from an individual who does not have Alzheimer’s disease. 8. The method of embodiment 1, wherein the anti-Aβ protofibril antibody is lecanemab. 9. A method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising: determining a first level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject, wherein the first level of the AMP is altered in CSF from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10; administering to the subject a first therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody; determining a second level of the AMP in CSF from the subject; and administering a second therapeutically effective dose of the AD therapy if there is a change from the first level of the AMP to the second level of the AMP. 10. The method of embodiment 9, wherein the antimicrobial peptide comprises any one of SEQ ID NOs: 13-36. 11. The method of embodiment 9, wherein the subject is cognitively impaired. Attorney Docket Number 08061.0063-00304 12. The method of embodiment 9, wherein the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1- 42 / Aβ1-40 ratio in CSF that is below 0.065. 13. The method of embodiment 9, wherein the control is the level of AMP a biofluid (e.g., CSF) from an individual who does not have Alzheimer’s disease. 14. The method of embodiment 9, wherein the anti-Aβ protofibril antibody is lecanemab. 15. A method of monitoring treatment efficacy in a subject having or suspected of having AD, comprising: determining a first level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject, wherein the first level of the AMP is altered in CSF from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10; administering to the subject a first therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody; and measuring a second level of the AMP in CSF from the subject, wherein a second level of the AMP that is different from the first level indicates effective treatment. 16. The method of embodiment 15, wherein the antimicrobial peptide comprises any one of SEQ ID NOs: 13-36. 17. The method of embodiment 15, wherein the subject is cognitively impaired. 18. The method of embodiment 15, wherein the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1- 42 / Aβ1-40 ratio in CSF that is below 0.065. 19. The method of embodiment 15, wherein the control is the level of AMP a biofluid (e.g., CSF) from an individual who does not have Alzheimer’s disease. 20. The method of embodiment 15, wherein the anti-Aβ protofibril antibody is lecanemab. Attorney Docket Number 08061.0063-00304 21. A method of diagnosing AD in a subject, comprising: determining a level of one or more antimicrobial peptides (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject, wherein the AMP is selected from any of those listed in Table 10, and comparing the level of the AMP to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein an altered level of the AMP in CSF from the subject as compared to the control indicates that the subject has AD. 22. The method of embodiment 21, wherein the antimicrobial peptide comprises any one of SEQ ID NOs: 13-36. 23. The method of embodiment 21, wherein the subject is cognitively impaired. 24. The method of embodiment 21, wherein the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1- 42 / Aβ1-40 ratio in CSF that is below 0.065. 25. The method of embodiment 21, wherein the control is the level of AMP a biofluid (e.g., CSF) from an individual who does not have Alzheimer’s disease. BRIEF DESCRIPTION OF DRAWINGS Figure 1 shows an overview of cohort demographics (Fig.1A) and study methodology (Fig.1B). Figure 2 shows the de novo-assisted pipeline used to identify differential expression of 24 AMPs (q<0.2) in the CSF of Aβ+ demented subjects. Figure 3 is a volcano plot using 320 CSF peptides in cognitively impaired subjects. 24 / 320 CSF AMP peptides were differentially regulated in subjects that are Aβ+ (AD) vs Aβ- (non-AD) comparisons (q <0.2). Figure 4 shows a heat map showing 24 significantly altered AMPs (q<0.2) in subjects that are Aβ+ (AD) and Aβ- (non-AD) dementia. Figure 5 shows a box plot showing increased expression of antimicrobial peptides from Clusterin (Fig.5A) and Chromogranin A (Fig.5B) proteins in CSF of Aβ-driven dementia. Attorney Docket Number 08061.0063-00304 Figure 6 shows MEGENA data-driven peptide co-expression network that consisted of 642 modules (Fig.6A). CMGA peptide represented a hub in c1_16 and c1_179 modules and exhibited high correlation with a dementia-linked neurosecretory protein VGF (Fig.6B). Gene Ontology analysis of c1_16 module proteins showed enrichment of many neurodegeneration associated pathways (Fig.6C). DETAILED DESCRIPTION Alzheimer’s disease (AD) is characterized by progressive decline in cognitive function, accompanied by pathological hallmarks in the structure and function of the brain. One hallmark of AD is the formation of insoluble aggregates, composed of amyloid beta (Aβ) plaques or tau neurofibrillary tangles (NFTs) (also, tau tangles or fibrillary tangles). Each of Aβ and tau have been proposed to play a central, even causative, role in the pathogenesis of AD. Acting either independently of each other or synergistically, Aβ plaques and tau tangles contribute to synaptic dysfunction, loss of neural connectivity, and neuronal death, as well as other associated pathologies. One such pathology is chronic neuroinflammation, which may provide a link between Aβ plaques and NFTs (Chen and Yu, Journal of Neuroinflammation, 2023.20:165). In the brain, innate immune cells such as microglia and astrocytes contribute to chronic inflammation, e.g., through sustained activation that produces high levels of pro- inflammatory factors. Innate immune cells appear to be both activated by and to enhance activation of Aβ and tau in feedback loops. In one theory, called the “Antimicrobial Protection Hypothesis,” (Moir et al., Alzheimer’s Dementia, 2018; 14: 1602-1614), Aβ deposition may be an innate immune response to a challenge such as a microbial pathogen, as Aβ oligomers may trap pathogens to protect against infection. The Aβ aggregates can be degraded and phagocytosed by microglia, however, in AD when Aβ levels are elevated, the microglia are in a chronically activated state that paradoxically leads to reduced Aβ clearance, further activates the microglia, and eventually leads to tangle formation and neurodegeneration (Prosswimmer et al., Scientific Reports, 2024.14:5376). The observations of Aβ are consistent with studies that implicate other antimicrobial peptides in plaque and tangle pathology (Bruno et al., Antibiotics, 2022; 11:726). In addition to Aβ, lactoferrin, defensins, cystatins, thymosin β4, LL37, histatin and statherin have been reported to show antimicrobial activity and have been found in plaques or biofluids from AD patients. Bruno et al. (2022, supra) suggest that these AMPs may be used as biomarkers for AD diagnosis. Attorney Docket Number 08061.0063-00304 Identification of additional AMPs with improved association with AD may serve to provide biomarkers for different stages of the disease and / or various pathologies. Identification of these AMPs is complicated by challenges in confirming the identity of peptides in biofluids, and in establishing that their levels robustly correlate with occurrence of the disease. Disclosed herein are novel AMPs which may be used in a variety of methods for diagnosing, monitoring, and treating patients with AD, based on AMP levels in biofluid samples, e.g., CSF or blood. The present disclosure relates to methods of diagnosing Alzheimer’s disease (AD), treating AD, and / or monitoring treatment efficacy, based on a determination of the levels of at least one antimicrobial peptide (AMP) in a biofluid from a subject having or suspected of having AD. Antimicrobial Peptides One aspect of the present disclosure relates to an AMP selected from the 24 AMP listed in Table 10, any of which may be measured (alone or in combination) at any step of treating a subject who has, is suspected of having, or is at risk of developing AD. In some embodiments, the AMP may be used for selecting a subject for treatment with a therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody, treating the subject with the AD therapy, reducing a brain Aβ level by administering the AD therapy, reducing a brain tau level by administering the AD therapy, monitoring efficacy of treatment, and / or altering a treatment regimen that comprises administration of AD therapy. In some embodiments, the AMP is selected from Table 10. Table 10 provides the sequence of the AMP and the human protein to which it maps. In some embodiments, the AMP is a peptide of Clusterin (CLUS), e.g., a peptide that is or comprises amino acids 69-79, 155-167, 259-276, 363-371, 386-395, 388-408, 391-408, or 418-425 of Clusterin. In some embodiments, the AMP is a peptide of Chromogranin A (CMGA), e.g., a peptide that is or comprises amino acids 19-27, 20-46, 21-27, or 78-88 of Chromogranin A. In some embodiments, the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 Attorney Docket Number 08061.0063-00304 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC). In some embodiments, the AMP is selected from Table 10. In some embodiments, the level (e.g., concentration, expression, quantity, etc.) of the AMP in a biofluid sample from a subject is increased relative to a control (e.g., an AMP level from an individual who does not have AD). In some embodiments, the AMP may be up- regulated in the biofluid sample from the subject. In some embodiments, the level (e.g., concentration, expression, quantity, etc.) of the AMP in a biofluid sample from a subject is decreased relative to a control (e.g., an AMP level from an individual who does not have AD). In some embodiments, the AMP may be down-regulated in the biofluid sample from the subject. In some embodiments, the difference between the AMP level in the biofluid sample from the subject and the AMP level in the biofluid sample from the control is used for the methods disclosed herein. 1. Selecting a subject for treatment One aspect of the present disclosure relates to a method of selecting a subject for a treatment comprising an AD therapy, wherein the method comprises a) obtaining a measurement of a level of at least one antimicrobial peptide (AMP) in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) selecting the subject for treatment if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD). Another aspect of the present disclosure relates to a method of selecting a subject for a treatment comprising an AD therapy, wherein the method comprises a) obtaining a measurement of a level of at least one antimicrobial peptide (AMP) in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); and b) selecting the subject for treatment if the level of at least one antimicrobial peptide (AMP) is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD). In some embodiments, the AMP is a peptide listed in Table 10. Attorney Docket Number 08061.0063-00304 In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in a biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the level of the same AMP in a control sample. In some embodiments, the level of at least one AMP from the subject is increased as compared to the control. In some embodiments, the level of at least one AMP from the subject is decreased as compared to the control. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The level of at least one AMP in the biofluid (e.g., CSF) from the subject may be compared to the level of at least one AMP in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an Attorney Docket Number 08061.0063-00304 anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of one or more biomarkers in addition to in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, phosphorylated-tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of p-tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231, and / or MTBR-tau243 indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. 2. Monitoring treatment efficacy An aspect of the present disclosure relates to a method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a first measurement of an AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a second measurement of the AMP level in a biofluid sample in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level ratio as compared to first AMP level is an indicator of treatment efficacy. Attorney Docket Number 08061.0063-00304 An aspect of the present disclosure relates to a method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a first measurement of an AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2- microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a second measurement of the AMP level in a biofluid sample in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level as compared to first AMP level is an indicator of treatment efficacy. In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in the biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the level of the same AMP in a control sample. Changes in the two or more AMPs may be independent of each other (e.g., one may increase and the other decrease). In some embodiments the first AMP level will show a change (e.g., an increase or a decrease) as compared to the second AMP level from the subject after treatment. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the treatment is effective. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicating that the treatment is not effective. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the treatment is not effective. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicating that the treatment is effective. In some embodiments, the first AMP level from the subject shows no change as compared to the second AMP level, and this indicates that the treatment is effective. Attorney Docket Number 08061.0063-00304 In some embodiments, the first AMP level from the subject shows no change as compared to the second AMP level, and this indicates that the treatment is not effective. In some embodiments, the measurement of the first AMP level may be obtained from the subject prior to treatment. In some embodiments, the measurement of the first AMP level is a measurement of the AMP level in a subject who had already begun treatment without having a prior measurement of the AMP level. In some embodiments, the steps b) obtaining a second measurement of the AMP level in a biofluid sample in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and step c) comparing the first AMP level to the second AMP level, of the method of monitoring treating efficacy may be repeated at least once in order to continue monitoring the treatment efficacy over time. In an exemplary example, the method further comprises, after step c), obtaining a measurement of a third AMP level in a third biofluid sample, e.g., a CSF or blood sample, from the subject at a time point after obtaining the second biofluid sample and comparing the third AMP level to an earlier measurement of the AMP level (e.g., the first and / or the second AMP level), wherein a change in the third AMP level as compared to the earlier AMP level is an indicator of treatment efficacy. In some embodiments, steps b) and c) may be repeated for as long as the subject receives treatment. In some embodiments, steps b) and c) may be repeated at regular intervals, e.g., once weekly, biweekly, monthly, quarterly, semiannually, or yearly. In some embodiments, the method of monitoring treatment efficacy may further comprise, after step c), a further step of d) modifying the treatment by administering a modified treatment comprising a further therapeutically effective dose of the AD therapy. For example, if the treatment is not effective, the dose may be modified by increasing the size of the dose, increasing the frequency of administration, and / or changing the route of administration. In some embodiments, an additional therapeutic may be added, e.g., if the AD therapy comprises an anti-Aβ protofibril antibody (e.g., lecanemab), an anti-tau antibody (e.g., E2814) may be added. Conversely, if the treatment is effective, the dose may be modified by decreasing the size of the dose, increasing the frequency of administration, and / or changing the route of administration. In some embodiments, the subject may be switched from a treatment administered according to a treatment dosing regimen to a treatment administered according to a maintenance dosing regimen. In some embodiments, the treatment may be discontinued. In some embodiments, steps b) and c) may be repeated for as long as the subject receives treatment, e.g., after the subject receives a modified treatment. In some embodiments, steps b) and c) may be repeated if the subject no longer Attorney Docket Number 08061.0063-00304 receives treatment, e.g., to continue monitoring treatment efficacy after the treatment has been discontinued. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of Attorney Docket Number 08061.0063-00304 one or more biomarkers in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, and / or phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p- tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. 3. Adjusting a treatment regimen An aspect of the present disclosure relates to a method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) comparing the level of at least one AMP to a control sample, e.g., an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) adjusting the treatment regimen, e.g., by adjusting the size of the dose, the frequency of administration, and / or the route of administration, if the AMP level differs from the control sample. A further aspect of the present disclosure relates to a method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin- 40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) comparing the level of at least one AMP to a control sample, e.g., an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) adjusting the treatment Attorney Docket Number 08061.0063-00304 regimen, e.g., by adjusting the size of the dose, the frequency of administration, and / or the route of administration, if the AMP level differs from the control sample. In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in a biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the level of the same AMP in a control sample. Changes in the two or more AMPs may be independent of each other (e.g., one may increase and the other decrease). In some embodiments, the control sample is a measurement of an AMP level (e.g., the same at least one AMP measured in a subject) obtained from a biofluid sample, e.g., a CSF or blood sample, from a control subject. The control subject may be an individual who does not have AD. In some embodiments, the control sample is a measurement of a previous AMP level obtained from a biofluid sample, e.g., a CSF or blood sample from the subject receiving the treatment. For example, the control sample may have been obtained from the subject prior to the treatment, or at an earlier time during the course of treatment, prior to performing the steps of the method. In some embodiments, the measurement of the AMP level may be obtained prior to treatment. In some embodiments, the measurement of the AMP level is a first measurement of the AMP level in a subject who had already begun treatment without having a prior measurement of the AMP level. In some embodiments, the treatment regimen (also called a “dosing regimen” or “treatment dosing regimen”), comprises a schedule specifying doses of the AD therapy administered per unit of time, including the number of doses over a given time period and the elapsed time between doses. In some embodiments, the treatment regimen comprises administering the AD therapy at a specified dose, according to a schedule (e.g., on a repetitive basis). In some embodiments, adjusting the treatment regimen comprises increasing the size of the dose, increasing the frequency of administration, and / or changing the route of administration of the AD therapy if the AMP level is higher than the control sample. In some embodiments, an additional therapeutic may be added. Attorney Docket Number 08061.0063-00304 In some embodiments, adjusting the treatment regimen comprises decreasing the size of the dose, decreasing the frequency of administration, and / or changing the route of administration if the AMP level is lower than the control sample. In some embodiments, the subject may be switched from a treatment comprising administration of a therapeutically effective dose of the AD therapy (e.g., an initiation dose) administered according to an initiation dosing regimen to a treatment comprising administration of a therapeutically effective dose of the AD therapy (e.g., a maintenance dose) administered according to a maintenance dosing regimen. In some embodiments, the treatment may be discontinued. In some embodiments, the steps of a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, and b) comparing the level of at least one AMP to a control sample, e.g., an AMP level in an individual who does not have Alzheimer’s disease (AD) of the method of adjusting a treatment regimen may be repeated at least once in order to monitor the efficacy of the adjusted treatment regimen and optionally, to further adjust the treatment regimen. In an exemplary example, the method further comprises, after step c), obtaining a further measurement of a level of at least one AMP in a further biofluid sample, e.g., a CSF or blood sample, from the subject at a time point after adjusting the treatment regimen, and comparing the further measurement to the measurement of the level of at least one AMP obtained prior to adjusting the treatment regimen or to a control sample (e.g., an AMP level in an individual who does not have AD). In some embodiments, if the further measurement of the level of at least one AMP still differs from the control sample, the treatment may be adjusted further. The steps a) and b) may be repeated for as long as the subject receives the treatment or the adjusted treatment. In some embodiments, steps b) and c) may be repeated if the subject no longer receives treatment, e.g., to continue monitoring treatment efficacy after the treatment has been discontinued. In some embodiments, steps b) and c) may be repeated at regular intervals, e.g., once weekly, biweekly, monthly, quarterly, semiannually, or yearly. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a Attorney Docket Number 08061.0063-00304 t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of one or more biomarkers in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, and / or phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p- tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231) indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some Attorney Docket Number 08061.0063-00304 embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. 4. Detecting a decrease in a brain Aβ level or a brain tau level An aspect of the present disclosure relates to a method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein a change in the AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject. An aspect of the present disclosure relates to a method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein a change in the AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject. In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in a biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the Attorney Docket Number 08061.0063-00304 level of the same AMP in a control sample. Changes in the two or more AMPs may be independent of each other (e.g., one may increase and the other decrease). In some embodiments the first AMP level will show a change (e.g., an increase or a decrease) as compared to the second AMP level from the subject after treatment. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the brain Aβ level is decreased. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the brain Aβ level is decreased. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the brain Aβ level is not decreased. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the brain Aβ level is not decreased. An aspect of the present disclosure relates to a method of detecting a decrease in a brain tau level (e.g., a reduction in tau tangles) in a subject receiving a treatment comprising a therapeutically effective dose of an anti-tau antibody, wherein the method comprises a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment with the anti-tau antibody wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein a change in the AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject. An aspect of the present disclosure relates to a method of detecting a decrease in a brain tau level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, wherein the method comprises a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and Attorney Docket Number 08061.0063-00304 second AMP levels, wherein a change in the AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the brain tau level is decreased. In some embodiments, a decrease in a brain tau level is a decrease in tau tangles. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the brain tau level is decreased. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the brain tau level is not decreased. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the brain tau level is not decreased. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level (e.g., the same at least one AMP as measured in the subject) in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, Attorney Docket Number 08061.0063-00304 the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of one or more biomarkers in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, and / or phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p- tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231) indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. 5. A method of decreasing tau tangles A further aspect of the present disclosure relates to a method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the a first AMP level is changed as compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles, optionally wherein the anti-tau antibody comprises three heavy Attorney Docket Number 08061.0063-00304 chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3). A further aspect of the present disclosure relates to a method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the a first AMP level is changed as compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles, optionally wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3). In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in a biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the level of the same AMP in a control sample. Changes in the two or more AMPs may be independent of each other (e.g., one may increase and the other decrease).In some embodiments, tangles are reduced by preventing, reducing, and / or slowing formation of new Attorney Docket Number 08061.0063-00304 tau tangles; and / or by promoting, increasing, and / or speeding up breakdown of existing tau tangles, as evidenced by a reduction in an AMP level in a sample taken after treatment. In some embodiments, tau tangles may be measured by tau PET imaging, e.g., using a radioligand. In some embodiments, tau PET imaging may be used, e.g., together with the change in the AMP level (e.g., an increase or a decrease in the AMP level), to establish and / or confirm the reduction in tau tangles. In various embodiments, a method for identifying tau tangles in a subject comprises a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject; b) identifying tau tangles in the subject if the level of at least one AMP is changed as compared to a control sample, e.g., compared to a level of an AMP in an individual who does not have Alzheimer’s disease (AD). In some embodiments, a treatment comprising a therapeutically effective dose of an anti-tau antibody (e.g., E2814) may be administered to the subject in whom tau tangles have been identified. In some embodiments, a treatment comprising a therapeutically effective dose of an anti-Aβ protofibril antibody (e.g., lecanemab) may be administered to the subject in whom tau tangles have been identified. In some embodiments, measurements of further level of at least one AMP may be obtained from further biofluid samples (e.g., a further CSF or blood sample) in order to determine if the treatment has changed the level of at least one AMP. In some embodiments, a change in the level of at least one AMP over time indicates that the treatment is reducing tau tangles. In some embodiments, the efficacy of the treatment (e.g., the anti-tau antibody administered in conjunction with the anti-Aβ protofibril antibody) may be determined by further measurements of the level of at least one AMP in a biofluid sample (e.g., a CSF or blood sample) in the subject obtained during the time course of treatment, and optionally, the treatment may be adjusted. In some embodiments, the subject may be switched to a maintenance dose of the AD therapy, e.g., a maintenance dose of the anti-tau antibody or a maintenance dose of the anti-Aβ protofibril antibody. In some embodiments the first AMP level will show a change (e.g., an increase or a decrease) as compared to the second AMP level from the subject after treatment. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the tau tangles are decreased. In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the tau tangles are decreased. In some embodiments, the first AMP level from the subject is increased as compared to the second AMP level, and this indicates that the tau tangles are not decreased. Attorney Docket Number 08061.0063-00304 In some embodiments, the first AMP level from the subject is decreased as compared to the second AMP level, and this indicates that the tau tangles are not decreased. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level (e.g., the same at least one AMP as measured in the subject) in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, Attorney Docket Number 08061.0063-00304 such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of one or more biomarkers in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, and / or phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p- tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231) indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. 6. A method of treating a subject An aspect of the present disclosure relates to method of treating a disorder in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), wherein the method comprises: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD). An aspect of the present disclosure relates to method of treating a disorder in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), wherein the method comprises: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2- microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD). Attorney Docket Number 08061.0063-00304 In some embodiments, the AMP is a peptide listed in Table 10. In some embodiments, levels of two or more AMPs (e.g., from the AMPs listed in Table 10) may be obtained in a biofluid sample e.g., a CSF or blood sample, from the subject and compared to the levels of the two more AMPs in a control sample, e.g., in an individual who does not have AD. For example, levels of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 AMPs may be obtained from the subject and compared to levels in the control sample. In some embodiments, the level of at least one AMP among the two or more AMPs will show a change (e.g., an increase or a decrease) as compared to the level of the same AMP in a control sample. Changes in the two or more AMPs may be independent of each other (e.g., one may increase and the other decrease). In some embodiments the first AMP level will show a change (e.g., an increase or a decrease) as compared to the second AMP level from the subject after treatment. In some embodiments, the AMP level from the subject is increased as compared to the control. In some embodiments, the AMP level from the subject is decreased as compared to the control. In some embodiments, the disorder (e.g., disease) is Alzheimer’s disease (AD). In some embodiments, the disorder is mild AD. In some embodiments, the disorder is early AD. In some embodiments, the disorder is moderate AD. In some embodiments, the disorder is severe AD. In some embodiments, the disorder is pre-AD. In some embodiments, the disorder is a neurological disorder (e.g., a neurodegenerative disorder or disease) characterized by Aβ peptide-containing soluble and / or insoluble Aβ aggregates. Exemplary disorders include but are not limited to Down’s Syndrome, chronic traumatic encephalopathy, cerebral amyloid angiopathy, and Lewy Body Dementia. In some embodiments, treating the disorder comprises at least one of inhibiting the disorder, slowing progression of the disorder, delaying progression, arresting its development, reversing progression of disorder (e.g., reversing aggregation of tau), preventing the onset or development of the disorder, relieving or ameliorating one or more symptoms or underlying condition(s) of the disorder, curing the disorder, improving one or more clinical metrics, or preventing reoccurrence of one or more symptoms of the disorder. In some embodiments, treating a disorder comprises at least one of reducing a brain Aβ level, reducing a brain tau level, improving cognition, and altering biomarkers associated with AD pathology. In some embodiments, the method of treating the disorder further comprises steps of monitoring treatment efficacy and / or adjusting a treatment regimen. In some embodiments, Attorney Docket Number 08061.0063-00304 the method further comprises, after steps of a) obtaining a measurement of an AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject; and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy, applying further step c) obtaining a further measurement of the level of at least one AMP (e.g., a further AMP level) in a second biofluid sample, e.g., a CSF or blood sample, from the subject; d) determining that the further AMP level has changed as compared the level of at least one AMP obtained prior to administration of the AD therapy; and e) administering a further therapeutically effective dose of the AD therapy to the subject. In some embodiments, the first AMP level is increased as compared to the second AMP level. In some embodiments, the first AMP level is decreased as compared to the second AMP level. In some embodiments, the further therapeutically effective dose is an adjusted dose (e.g., the size of the dose, the frequency of administration, and / or the route of administration is adjusted as compared to the treatment first administered to the subject). In some embodiments, the further therapeutically effective dose is an adjusted dose administered as part of an initiation dosing regimen, wherein both the treatment first administered to the subject and the further therapeutically effective dose are part of the initiation dosing regimen. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. Attorney Docket Number 08061.0063-00304 In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD). For example, the subject may have symptoms of AD, such as cognitive impairment or high levels of amyloid PET or tau PET, or altered levels of one or more biomarkers in addition to the AMP (e.g., MTBR-tau243, Aβ42, Aβ40, Aβ42 / 40 ratio, total tau, and / or phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p- tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231) indicate that the subject may have AD. In some embodiments, the individual may have additional risk factors for developing AD, such as family history, genetic background, gender, age over 60 years, head injury, co-morbidities (e.g., vascular disease and / or diabetes), or certain lifestyle factors such as smoking, consuming alcohol, or limiting physical activity. In some embodiments, the subject has severe AD. In some embodiments, the subject has moderate AD. In some embodiments, the subject has mild AD. In some embodiments, the subject has early-AD. In some embodiments, the subject has pre-AD. In some embodiments, the subject is amyloid positive. In some embodiments, the subject is amyloid positive and cognitively impaired. In some embodiments, an AD therapy disclosed herein (e.g., an anti-tau antibody such as E2814 or an antibody comprising the CDRs and / or variable domains from E2814, and / or an anti-Aβ protofibril antibody such as lecanemab or an antibody comprising the CDRs and / or variable domains from lecanemab), is comprised in a pharmaceutical composition for the treatment of a subject having, suspected of having, or at risk for Attorney Docket Number 08061.0063-00304 developing Alzheimer’s disease (AD), wherein a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject is changed (e.g., increased or decreased) compared to a control sample, e.g., compared to a level of at least one AMP (e.g., the same at least one AMP measured in the subject) in an individual who does not have Alzheimer’s disease (AD). In some embodiments, the pharmaceutical composition comprises at least one pharmaceutically acceptable carrier. In some embodiments, an AD therapy disclosed herein (e.g., an anti-tau antibody such as E2814 or an antibody comprising the CDRs and / or variable domains from E2814, and / or an anti-Aβ protofibril antibody such as lecanemab or an antibody comprising the CDRs and / or variable domains from lecanemab), is used in the manufacture of a medicament for the treatment of a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), wherein a level of at least one AMP concentration in a biofluid sample, e.g., a CSF or blood sample, from the subject is elevated compared to a control sample, e.g., compared to a level of at least one AMP (e.g., the same at least one AMP measured in the subject) concentration in an individual who does not have Alzheimer’s disease (AD). In some embodiments, (e.g., an anti-tau antibody such as E2814 or an antibody comprising the CDRs and / or variable domains from E2814, and / or an anti-Aβ protofibril antibody such as lecanemab or an antibody comprising the CDRs and / or variable domains from lecanemab), is for use in the treatment of a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), wherein a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject is elevated compared to a control sample, e.g., compared to a level of at least one AMP (e.g., the same at least one AMP measured in the subject) in an individual who does not have Alzheimer’s disease (AD). 7. A method of treatment for Alzheimer’s disease One aspect of the present disclosure relates to method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising: determining an altered level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10, and administering to the subject a therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. Attorney Docket Number 08061.0063-00304 A further aspect of the present disclosure relates to method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising: determining an altered level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC), and administering to the subject a therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. A protein may be known by other aliases, or may be known by the name of a gene encoding the protein. For example, Secretogranin-1 (SCG1) may also be known as SgI, SCG1, Secretogranin B, or Chromogranin B. RPS27A gene may be known as Ribosomal Protein S27a, as Ubiquitin Carboxyl Extension Protein 80, UBCEP80, Ubiquitin-40S Ribosomal Protein S27a, UBCEP1, Uba80, or UBA80. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, an altered level in an AMP in the biofluid is an increased level of the AMP. For example, the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. In some embodiments, the altered level in an AMP in the biofluid is a decreased level Attorney Docket Number 08061.0063-00304 of the AMP, e.g., the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. 8. Evaluating treatment efficacy An AMP level may be obtained at different time points. For example, the AMP level in the biofluid of a subject may be determined at two or more time points, wherein a first time point may be prior to treatment for AD or early during the treatment regimen, while a second time point may be at later time in the treatment regimen. Thus, a further aspect of the present disclosure relates to a method of treating Alzheimer’s disease (AD) in a subject having or suspected of having AD, comprising determining a first level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject, wherein the first level of the AMP is altered in CSF from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10; administering to the subject a first therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody; determining a second level of the AMP in CSF from the subject; and administering a second therapeutically effective dose of the AD therapy if there is a change from the first level of the AMP to the second level of the AMP. Attorney Docket Number 08061.0063-00304 In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, an altered level in an AMP in the biofluid is an increased level of the AMP. For example, the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. In some embodiments, the altered level in an AMP in the biofluid is a decreased level of the AMP, e.g., the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). A further aspect of the present disclosure relates to a method of monitoring treatment efficacy in a subject having or suspected of having AD, comprising determining a first level of at least one antimicrobial peptide (AMP) in a biofluid, e.g., a cerebrospinal fluid Attorney Docket Number 08061.0063-00304 (CSF), from the subject, wherein the first level of the AMP is altered in CSF from the subject as compared to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein the AMP is selected from any of those listed in Table 10; administering to the subject a first therapeutically effective dose of an AD therapy, e.g., an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody; and measuring a second level of the AMP in CSF from the subject, wherein a second level of the AMP that is different from the first level indicates effective treatment. In some embodiments, treatment may be changed if a difference between the first level of the AMP and the second level of the AMP indicates effective treatment. For example, a treatment may be reduced, e.g., in dosage and / or frequency of administration. In some embodiments, treatment may not be changed if the first level of the AMP is not different from the second level of the AMP. For example, a treatment may be continued. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, an altered level in an AMP in the biofluid is an increased level of the AMP. For example, the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. In some embodiments, the altered level in an AMP in the biofluid is a decreased level of the AMP, e.g., the subject having or suspected of having AD may have an increased level of the AMP in the biofluid as compared to the level of the AMP in the control. Attorney Docket Number 08061.0063-00304 In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. 9. A method of diagnosis for AD An aspect of the present disclosure relates to a method of diagnosing AD in a subject, comprising determining a level of one or more antimicrobial peptides (AMP) in a biofluid, e.g., a cerebrospinal fluid (CSF), from the subject, wherein the AMP is selected from any of those listed in Table 10, and comparing the level of the AMP to a control, e.g., CSF from an individual who has not been diagnosed with AD, wherein an altered level of the AMP in CSF from the subject as compared to the control indicates that the subject has AD. In some embodiments, the AMP is about 10-100 amino acids in length, e.g, about 12-50 amino acids in length. The peptide may correspond to any region of the full-length protein. In some embodiments, the AMP comprises any one of SEQ ID NOs: 27-50. In some embodiments, the subject having or suspected of having AD is cognitively impaired. For example, the individual may have dementia. The subject may be Aβ+, for example, as determined by measurement of Aβ levels in a biofluid, or as determined by imaging, e.g., amyloid PET imaging. In some embodiments, the subject has one or more of a t-tau level in CSF that is above 400 ng / L, an Aβ1-42 level in CSF that is below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio in CSF that is below 0.065. The AMP level in the biofluid (e.g., CSF) from the subject may be compared to the AMP level in a control. In some embodiments, the control is the level of AMP in CSF from an individual who does not have Alzheimer’s disease. In some embodiments, the individual Attorney Docket Number 08061.0063-00304 who has not been diagnosed with AD. In some embodiments, the individual is cognitively impaired. For example, the individual may have dementia. In some embodiments, the individual is Aβ-. In some embodiments, the individual does not have AD. In some embodiments, the biofluid is a cerebrospinal fluid (CSF). In some embodiments, the biofluid is blood. In some embodiments, the biofluid is one or more of CSF, blood, serum, plasma, saliva, tears, sweat, or any other biofluid that may be collected from a body. AD therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy is an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the AD therapy is an anti-tau antibody. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. Alzheimer’s Disease Therapy Alzheimer’s disease (AD) therapy may be any treatment or therapeutic that is administered to a subject to reduce symptoms and / or progression of the AD. In some embodiments, AD therapy may be any treatment that delays progression of amyloid pathology, tau pathology, and / or clinical symptoms in a subject who has, is suspected of having, or is at risk for developing AD. In some embodiments, the AD therapy is administered to a subject based on measurements of antimicrobial peptides (AMPs) in a biofluid sample from the subject. In some embodiments, the AD therapy comprises an antibody. In some embodiments, the AD therapy is an anti-Aβ protofibril antibody (e.g., lecenemab). In some embodiments, the AD therapy is an anti-tau antibody (e.g., E2814). In some embodiments, the AD therapy is a combination of an anti-Aβ protofibril antibody (e.g., lecenemab) and an anti-tau antibody (e.g., E2814). In some embodiments, the AD therapy may be administered according to an initiation dosing regimen, and optionally, a maintenance dosing regimen. Exemplary dosage Attorney Docket Number 08061.0063-00304 regimens for lecanemab, E2814, and a combination thereof are disclosed in WO2023 / 111618, WO2023 / 114586, and PCT / US2024 / 033125, which are incorporated herein by reference. a. Anti-Aβ protofibril antibodies In some embodiments, when an AMP level from a biofluid sample (e.g., a CSF sample or a blood sample) differs from an AMP level from a control (e.g., a biofluid sample from a subject who does not have AD), AD therapy comprising an anti-amyloid β (Aβ) treatment, e.g., an anti-Aβ protofibril antibody, may be administered. In some embodiments, the anti-Aβ protofibril antibody comprises a CDR, a variable region, a heavy chain, a light chain, or a constant region according to SEQ ID NOs: 1-12 listed in Tables 1-4. In some embodiments, the anti-Aβ protofibril antibody is lecanemab (also called BAN2401). In some embodiments, the anti-Aβ protofibril antibody comprises three heavy chain complementarity determining regions (HCDR1 , HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 2 (HCDR2), and SEQ ID NO: 3 (HCDR3); and three light chain complementarity determining regions (LCDR1 , LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 4 (LCDR1), SEQ ID NO: 5 (LCDR2), and SEQ ID NO: 6 (LCDR3) (Table 1). In some embodiments, the anti-Aβ protofibril antibody comprises a heavy chain variable region comprising an amino acid sequence of SEQ ID NO: 7 and a light chain variable region comprising an amino acid sequence of SEQ ID NO: 8 (Table 2). In some embodiments, the anti-Aβ protofibril antibody comprises human heavy and light chain variable region frameworks. In some embodiments, the anti-Aβ protofibril antibody comprises a human IgG1 heavy chain constant region, and a human Ig kappa light chain constant region. In some embodiments, the anti-Aβ protofibril antibody comprises a heavy chain comprising an amino acid sequence of SEQ ID NO: 9 and a light chain comprising an amino acid sequence of SEQ ID NO: 10 (Table 3). “CDRs” used herein in the context of an antibody sequence or structure refers to complementarity determining regions, which provide the main determinants of antigen binding. Generally, the antigen-binding site has six CDRs; three in the VH (HCDR1, HCDR2, HCDR3), and three in the VL (LCDR1, LCDR2, LCDR3). The CDRs may be determined according to the Kabat numbering scheme. which may be determined by according to the Kabat numbering scheme (Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md., 1991, hereafter referred to as “Kabat report”). Attorney Docket Number 08061.0063-00304 In some embodiments, the at least one anti-Aβ protofibril antibody comprises a human constant region. In some embodiments, the human constant region of the at least one anti-Aβ protofibril antibody comprises a heavy chain constant region chosen from IgG1, IgG2, IgG3, IgG4, IgM, IgA, IgE, and any allelic variation thereof as disclosed in the Kabat report. Any one or more of such sequences may be used in the present disclosure. In some embodiments, the heavy chain constant region is chosen from IgG1 and allelic variations thereof. The amino acid sequence of human IgG1 constant region is known in the art and set out in SEQ ID NO: 11 (Table 4). In some embodiments, the human constant region of the at least one anti-Aβ antibody comprises a light chain constant region chosen from κ-λ-chain constant regions and any allelic variation thereof as discussed in the Kabat report. Any one or more of such sequences may be used in the present disclosure. In some embodiments, the light chain constant region is chosen from κ and allelic variations thereof. The amino acid sequence of human κ chain constant region is known in the art and set out in SEQ ID NO: 12 (Table 4). b. Anti-tau antibodies In some embodiments, when an AMP level from a biofluid sample (e.g., a CSF sample or a blood sample) differs from an AMP level from a control (e.g., a biofluid sample from a subject who does not have AD), AD therapy comprising an anti-tau treatment, e.g., an anti-tau antibody, may be administered. In some embodiments, the anti-tau antibody comprises a CDR, a heavy chain variable region, a light chain variable region, or a constant region according to SEQ ID NOSs: 15-24 in Tables 6-8. In some embodiments, the anti-tau antibody is E2814. In some embodiments, the anti-tau antibody comprises six CDRs (HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3) comprising the amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), SEQ ID NO: 17 (HCDR3), SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3), as defined by Kabat (Table 6). In some embodiments, the anti-tau antibody comprises six CDRs (HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3) from a heavy chain variable region of SEQ ID NO: 21 and a light chain variable region of SEQ ID NO: 22 (e.g., as defined by Kabat or IMGT). In some embodiments, the anti-tau antibody comprises a heavy chain variable region of SEQ ID NO: 21 and a light chain variable region of SEQ ID NO: 22 (Table 7). In some embodiments, the anti-tau antibody comprises a human constant region. In some embodiments, the human constant region comprises a heavy chain constant region Attorney Docket Number 08061.0063-00304 chosen from IgG1, IgG2, IgG3, IgG4, IgM, IgA, IgE, and any allelic variation thereof as disclosed in the Kabat report. Any one or more of such sequences may be used in the present disclosure. In some embodiments, the heavy chain constant region comprises SEQ ID NO: 23 (Table 8). In some embodiments, the human constant region of the anti-tau antibody comprises a light chain constant region chosen from κ and λ-chain constant regions and any allelic variation thereof as discussed in the Kabat report. Any one or more of such sequences may be used in the present disclosure. In some embodiments, the light chain constant region comprises SEQ ID NO: 24 (Table 8). In some embodiments, the anti-tau antibody comprises E2814 or an antigen binding fragment thereof. E2814 is disclosed in US 2019 / 0112364 A1, incorporated by reference in its entirety, and which discloses E2814 as clone 7G6-HCzu25 / LCzu18, the sequences of which are incorporated by reference herein. In some embodiments, the anti-tau antibody is any of those disclosed in US 2019 / 0112364 A1, the disclosure of which is fully incorporated herein by reference. In some embodiments, the anti-tau antibody comprises the CDR and / or variable region sequences from antibody clone 7G6-HCzu25 / LCzu18 as disclosed in US 2019 / 0112364 A1, the sequences of which are incorporated by reference herein. In some embodiments, the anti-tau antibody is produced by antibody-producing cells deposited with the American Type Culture Collection (10801 University Blvd., Manassas, Va.20110-2209) on Oct.11, 2017, with Accession No. PTA-124524. Additional biomarkers In some embodiments, in addition to a change in the levels of one more more AMPs, a subject shows a change and / or difference in a measurement of one or more biomarkers associated with AD pathology prior to and / or during an AD treatment, e.g., a treatment disclosed herein. In some embodiments, the change and / or difference in the measurement is selected from (a) increased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), (b) increased tau in the brain, e.g., as measured by positron emission tomography (PET), (c) decreased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or Attorney Docket Number 08061.0063-00304 tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and (d) decreased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL). In some embodiments, the subject shows a change and / or difference in a measurement of one or more biomarkers associated with AD pathology during and / or after treatment. In some embodiments, the change and / or difference in the measurement is selected from (a) decreased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), (b) decreased tau in the brain, e.g., as measured by positron emission tomography (PET), (c) increased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and (d) increased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL). Amyloid PET PET imaging enables visualization of amyloid plaques in the brain, which were previously detected only by examining the brain at autopsy. Amyloid PET is a valuable tool for diagnosing AD and monitoring progression of the disease, as it has a high predictive accuracy for the presence of AD pathology. Amyloid PET may be used in conjunction with other biomarker measures, including any of those disclosed herein, preferably a blood or CSF marker, e.g. an AMP in blood or CSF. In some embodiments, the AMPs disclosed herein may be used to estimate (e.g., as a proxy) amyloid PET measurements. As used herein, the term “Amyloid PET” refers to Amyloid positron emission tomography imaging. In some embodiments, PET imaging (also referred to as a PET scan) is performed to assess for amyloid pathology (Hansson et al., Nature Medicine, 2021.27: 954– Attorney Docket Number 08061.0063-00304 963; Therriault et al., Nature Reviews Neurology, 2024.20: 232–244). In some embodiments, amyloid PET is assessed with a PET tracer and uses the same tracer in follow-up assessments. In some embodiments, the amyloid beta plaque levels in the brain are evaluated using PET imaging. In some embodiments, the PET imaging uses an amyloid PET tracer. In some embodiments, the PET imaging uses florbetaben (e.g., 18F-Florbetaben (Neuraceq®)), florbetapir (e.g., 18F-Florbetapir (Amyvid®)), and / or flutametamol (e.g., 18F-Flutemetamol (Vizamyl®)) In some embodiments, the PET imaging uses a florbetapir tracer. In some embodiments, the PET imaging used a flutemetamol tracer. In some embodiments, the PET imaging uses a florbetaben tracer. In some further embodiments, different tracers may yield different results. In some embodiments, the adjusted mean reduction threshold is dependent upon the tracer used. In some embodiments, a subject’s brain amyloid level is determined by visual reads of amyloid PET images and expressed as a PET standard uptake value ratio (SUVr value). In some embodiments, a brain amyloid level is reduced after administration of an AD therapy (e.g., an anti-Aβ protofibril antibody such as lecanemab or an anti-tau antibody such as E2814), concomitant with a change in a measurement of an AMP from Table 10. Tau PET PET imaging enables visualization of tau accumulation in the brain, which was previously detected only by examining the brain at autopsy. Tau PET is a valuable tool for diagnosing AD and monitoring progression of the disease, particularly as the tau NFT burden is strongly correlated with severity of clinical AD symptoms (Hansson et al., Nature Medicine, 2021.27: 954–963; Therriault et al., Nature Reviews Neurology, 2024.20: 232– 244). Tau PET may be used in conjunction with other biomarker measures, including any of those disclosed herein, preferably a blood or CSF marker, e.g. an AMP in blood or CSF. In some embodiments, the AMPs disclosed herein may be used to estimate (e.g., as a proxy) amyloid PET measurements. As used herein, “tau PET” refers to tau positron emission tomography. In some embodiments, PET imaging (e.g., a PET scan) is performed to assess tau pathology. In some embodiments, tau PET is assessed with a PET tracer and uses the same tracer in follow-up assessments. In some embodiments, a subject’s brain tau level is determined by visual reads of tau PET images and expressed as a PET standard uptake value ratio (SUVr value). In some Attorney Docket Number 08061.0063-00304 embodiments, a brain tau level is reduced after administration of an AD therapy (e.g., an anti- Aβ protofibril antibody such as lecanemab or an anti-tau antibody such as E2814), concomitant with a change in a measurement of an AMP from Table 10. Subjects having AD, suspected of having AD, or at risk of developing AD Subjects treated herein include those having AD or suspected of having AD. In some embodiments, the subject shows changes (e.g., an increase, a decrease, a change in the rate and / or extent of an increase, or a change in the rate and / or extent of the decrease) in one or more biomarkers associated with AD pathology (e.g., the AMPs described herein), as compared with a reference measurement. In some embodiments, the reference measurement may be a measurement taken from the same subject, e.g., at an earlier point in time, or a measurement in a part of the subject’s body, tissue, or fluids where the biomarkers levels do not change in response to AD pathology. In some embodiments, the reference measurement may be a measurement taken from another subject, such as a healthy control subject, or may be an average of measurements taken from more than one reference subject. In some embodiments, the subject may show a change and / or a difference in a measurement of an AMP level prior to treatment, e.g., an increase or a decrease in the AMP level as compared to the reference measurement, e.g., as compared to an earlier measurement in the subject or as compared to a control subject who does not have AD. In some embodiments, in addition or in lieu of an AMP level, the subject may show a change and / or a difference in a measurement of one or more biomarkers associated with AD pathology prior to treatment, e.g., one or more of (a) increased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), (b) increased tau in the brain, e.g., as measured by positron emission tomography (PET), (c) decreased cerebrospinal fluid levels of Aβ1-42 (e.g., a decreased ratio of Aβ1-42 / 1-40) and / or increased total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and (d) decreased blood serum or plasma levels of Aβ1-42 (e.g., a decreased ratio of Aβ1-42 / 1-40 in the plasma or serum), and / or increased total tau, phosphorylated tau (e.g., p-tau181, p- tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL), Attorney Docket Number 08061.0063-00304 as compared to a reference measurement (e.g., measurement from a healthy control). In some embodiments, the subject may show a change in the ratio of phosphorylated to non- phosphorylated Tau 217 (P-Tau217 / NP-Tau217 ratio, also called P-Tau217R or pTau217R) in blood plasma or serum, e.g., the ratio may be increased in subjects who have, are suspected of having, or are at risk of developing AD. Without being bound by theory, biomarkers as disclosed herein may be effective for predicting amyloid PET status (Rissman et al., 2024, Alzheimers & Dementia, 20(2): 1214-1224; Janelidze et al., 2022, Alzhimer’s & Dementia, 18:283-293) and for detecting and diagnosing AD (Hampel et al., 2023, Neuron, 111(18):2781-2799). In some embodiments, at least one of p-tau217 / np-tau217, Aβ42 / Aβ40, and p-tau181 / np-tau181 may be used to predict amyloid PET status. In some embodiments, a measurement of p-tau217 and / or Aβ42 / Aβ40 may be used to predict amyloid PET status. In some embodiments, a combination of p-tau217 and Aβ42 / Aβ40 may be used to predict amyloid PET status. In some embodiments, the ratios of p-tau217 / np-tau217 and Aβ42 / Aβ40 may be used in combination to predict amyloid PET status. In some embodiments, the subject is amyloid-positive, e.g., as indicated by a PET assessment, a CSF assessment of Aβ(1-42), MRI, and / or retinal amyloid accumulation. In some embodiments, a subject has AD, e.g., has been diagnosed with AD. For example, the subject may have been diagnosed with (a) mild cognitive impairment due to Alzheimer’s disease - intermediate likelihood and / or has been diagnosed as having mild Alzheimer’s disease dementia; (b) mild cognitive impairment due to Alzheimer’s disease - intermediate likelihood by National Institute of Aging – Alzheimer’s Association (NIA-AA) core clinical criteria; (c) mild cognitive impairment due to Alzheimer’s disease - intermediate likelihood by a CDR global score of 0.5 and a Memory Box score of 0.5 or greater before treatment; (d) mild cognitive impairment due to Alzheimer’s disease - intermediate likelihood by a history of subjective memory decline with gradual onset and slow progression over the last 1 year before treatment, e.g., as corroborated by an informant; (e) mild Alzheimer’s disease dementia by the NIA-AA core clinical criteria for probable Alzheimer’s disease dementia; or (f) mild Alzheimer’s disease dementia by a CDR score of 0.5 to 1.0 and a Memory Box score of 0.5 or greater before treatment. In some embodiments, the subject has early AD. The subject with early AD may have symptoms ranging in severity from mild cognitive impairment due to AD – intermediate likelihood to mild Alzheimer’s disease dementia. In some embodiments, subjects with early AD have MMSE scores of 22 to 30 and Clinical Dementia Rating (CDR) global range 0.5 to 1.0. Attorney Docket Number 08061.0063-00304 In some embodiments, the subject has a low tau PET level in a global brain measurement, for example, as measured by tau PET. A low level of tau PET may refer to a low level of tau aggregation as imaged by PET scan imaging, e.g., a low level of cortical tau aggregation. In some embodiments, a subject with low tau PET also has accumulation of tau in certain brain regions, e.g., one or more early Braak regions or a composite of regions where tau accumulates in early AD. In some embodiments, a subject may be classified as having a low level of tau if a level of tau as measured by PET using an MK tracer (e.g., MK6240) is below about 1.1, e.g., below about 1.0. In some embodiments, a patient may be classified as having a low level of tau if the tau PET level as measured using an MK tracer is below 1.06. In some embodiments, a patient may be classified as having an intermediate level of tau if the tau PET level as measured by MK tracer is between about 1.1 and 3.0, e.g., between 1.06 and 2.91. In some embodiments, a patient may be classified as having a high level of tau if the tau PET level as measured by MK tracer is above about 3.0, e.g., above 2.91. In some embodiments, a subject is suspected of having AD, e.g., based on one or more biomarkers and / or cognitive symptoms of dementia. In some embodiments, a subject is at risk for developing AD but has not yet exhibited cognitive symptoms of dementia. In some embodiments, a subject may have risk factors for AD, wherein the risk factors are related to age or genetic mutations. In some embodiments, the subject is ApoE4- positive. In some embodiments, the subject is at least 65 years old, e.g., 65 to 80 years old. In some embodiments, the subject is 55 to 64 years old and has at least one risk factor chosen from: (i) a first degree relative diagnosed with dementia onset before age 75; (ii) at least one apolipoprotein E4 variant (APOE4) allele; and (iii) elevated brain amyloid according to PET or cerebrospinal fluid (CSF) testing. In some embodiments, a subject at risk for AD has elevated brain amyloid, e.g., as measured by and / or confirmed by PET assessment, but does not exhibit any detectable cognitive symptoms. In some embodiments, a subject at risk for AD has a change in a biomarker such as amyloid PET; tau in the brain, e.g., as measured by positron emission tomography (PET), cerebrospinal fluid levels of one or more of Aβ1-42 (or a ratio of Aβ1-42 / 1-40 in the cerebrospinal fluid), total tau, phosphorylated tau (e.g., p- tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non- phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and neurofilament light chain (NfL), and / or a change in a blood serum or plasma levels of one or more of Aβ1-42 (or a ratio of Aβ1-42 / 1- Attorney Docket Number 08061.0063-00304 40), total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np- tau205, p-tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL), relative to a control subject or population. In some embodiments, a subject at risk for developing AD may have pre-AD (also referred to as preclinical AD, in which subjects are cognitively unimpaired but have elevated amyloid in the brain, e.g., as based on a change in one or more biomarkers associated with AD pathology). For example, the subject may show a change in one or more biomarkers associated with AD pathology, but no cognitive impairment, e.g., as measured by clinical symptoms of AD. In some embodiments, the subject has a Global Clinical Dementia Rating (CDR) score of 0. In some embodiments, the subject has a Mini-Mental State Examination (MMSE) score greater than or equal to 27, with educational adjustments. In some embodiments, the subject has a Wechsler Memory Scale-IV Logical Memory (subscale) II (WMS-IV LMII) score better than one standard deviation below age-adjusted mean in the WMS-IV LMII; namely a score of greater than 15 for a subject of age ranging from 50 to 64 years, of greater than 12 for a subject of age ranging from 65 to 69 years, of greater than 11 for a subject of age ranging from 70 to 74 years, of greater than 9 for a subject of age ranging from 75 to 79 years, and of greater than 7 for a subject of age ranging from 80 to 90 years. In some embodiments, the subject has a genetic mutation for a dominantly inherited Alzheimer’s disease, e.g., wherein the subject a genetic mutation in at least one of three genes — PSEN1, PSEN2, or APP. In some embodiments, the subject has a mutation in APP. In some embodiments, the subject has a dominantly inherited Alzheimer’s disease (DIAD). In some embodiments, the subject has mild-to-moderate AD, e.g., where mild AD may be associated with Mini-Mental State Examination [MMSE] scores ≥20) and may be characterized by forgetfulness and difficulties with activities of daily living (ADLs). Moderate AD may be associated with MMSE scores of about 10–19 and may be characterized by marked memory loss and a requirement for significant assistance with ADLs. Definitions The following are definitions of terms used in the present application. Attorney Docket Number 08061.0063-00304 As used herein, the singular terms “a,” “an,” and “the” include the plural reference unless the context clearly indicates otherwise. The phrase “and / or,” as used herein, means “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Thus, as a non-limiting example, “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in some embodiments, to A only (optionally including elements other than B); in other embodiments, to B only (optionally including elements other than A); in yet other embodiments, to both A and B (optionally including other elements); etc. As used herein, “at least one” means one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non- limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. As used herein, “about” when used in connection with doses, amounts, or ratios, include the value of a specified dose, amount, or ratio or a range of the dose, amount, or ratio that is recognized by one of ordinary skill in the art to provide a therapeutic effect equivalent to that obtained from the specified dose, amount, or ratio. The term “about” may refer to an acceptable error for a particular value as determined by one of skill in the art, which depends in part on how the values is measured or determined. In some embodiments, the term “about” means within 5% of a given value or range. When a number is recited, either alone or as part of a numerical range, it should be understood that the numerical value can vary above and below the stated value by up to a variance of + / - 10% of the stated value. When a range of values is listed herein, it is intended to encompass each value and sub-range within that range. For example, “2.5 mg / kg to 10 mg / kg” is intended to encompass, Attorney Docket Number 08061.0063-00304 for example, 2.5 mg / kg, 3 mg / kg, 3.5 mg / kg, 4 mg / kg, 4.5 mg / kg, 5 mg / kg, 5.5 mg / kg, 6 mg / kg, 6.5 mg / kg, 7 mg / kg, 7.5 mg / kg, 8 mg / kg, 8.5 mg / kg, 9 mg / kg, 9.5 mg / kg, 10 mg / kg, 2.5 mg / kg to 3 mg / kg, 2.5 mg / kg to 4.5 mg / kg, 3 mg / kg to 4.5 mg / kg, 4.5 mg / kg to 8 mg / kg, 2.5 mg / kg to 9 mg / kg, and so forth. As used herein, “adjusted mean change from baseline” refers to the use of a statistical analysis to calculate the change in a biomarker value over time. In some embodiments, a linear mixed-effects model (MMRM) is used to account for at least one additional covariate to determine the adjusted mean change from baseline. As used herein, an antimicrobial peptide (AMP), also called a host defense peptide (HDP), is a peptide of a class that may demonstrate activity against pathogens such as bacteria, viruses, and fungi, as well as certain cells such as transformed, mutated, or cancerous cells. AMPs may play a role in the innate immune response. The level of an AMP (also, “AMP level”) refers the concentration, and / or quantityof the AMP in a measured sample or in a subject. Amyloid β 1-42 (Aβ42) refers to an amyloid beta monomer from amino acid 1 to 42 of the full-length protein (Table 5, SEQ ID NO:13). Amyloid β 1-40 (Aβ1-40) refers to an amyloid beta monomer from amino acid 1 to 42 of the full-length protein (Table 5, SEQ ID NO:14). P-tau181 is human tau protein phosphorylated at threonine in position 181. P- tau217 is human tau protein phosphorylated at threonine in position 217. P-tau231 is human tau protein phosphorylated at threonine in position 231. P-tau205 is a human tau protein phosphorylated at threonine in position 205. Total tau or t-tau as used herein is a measure of total tau in a sample, e.g. a CSF sample, a plasma sample, a serum sample. MTBR-tau 243 is a peptide fragment of tau, spanning residues 243-254 in the microtubule-binding region of tau and is enriched in tau aggregates. MTBR-tau243 may be measured in a biofluid sample, e.g., CSF or blood, as a correlate of tau tangles, tau PET, and cognitive impairment. Patients with “preclinical AD” or “pre-AD” as described herein (also called patients who are “asymptomatic” for AD), are cognitively normal individuals with intermediate or elevated levels of amyloid in the brain and can be identified by asymptomatic stages with or without memory complaints and emerging episodic memory and executive function deficits. Cognitively normal can include individuals who are CDR 0, or individuals within the normal ranges of cognitive test scores (MMSE, International Shopping List Task, Attorney Docket Number 08061.0063-00304 Logical Memory, etc.). Preclinical AD occurs prior to significant irreversible neurodegeneration and cognitive impairment and is typically characterized by the appearance of in vivo molecular biomarkers of AD and the absence clinical symptoms. Preclinical AD biomarkers that may suggest the future development of Alzheimer’s disease include, but are not limited to, one or more of intermediate or elevated levels of amyloid in the brain by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20- 32), fluorodeoxyglucose (FDG) PET, or tau positron emission tomography (PET), cerebrospinal fluid level of Aβ1-42 and / or Aβ1-42 / 1-40 ratio, cerebrospinal fluid level of total tau, cerebrospinal fluid level of microtubule binding region (MTBR)-tau, cerebrospinal fluid level of neurogranin, cerebrospinal fluid level of neurofilament light chain (NfL), and blood biomarkers as measured in the serum or plasma (e.g. levels of Aβ1-42, the ratio of two forms of amyloid-β peptide (Aβ1-42 / 1-40 ratio, e.g., a ratio of between about 0.092-0.094 or below about 0.092), plasma levels of plasma total tau (T-tau), levels of phosphorylated tau (P-tau or p-tau) isoforms (including tau phosphorylated at 181 (P-tau181), at 205, (P-tau205), 217 (P-tau217), and 231 (P-tau231)), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL)). For example, it has been found that subjects treated with elenbecestat (E2609), a β-site amyloid precursor protein cleaving enzyme (BACE) inhibitor, who had amyloid baseline positron emission tomography (PET) standard uptake value ratios (SUVr values) of 1.4 to 1.9, exhibited the greatest slowing of cognitive decline while on treatment. See Lynch, S. Y. et al. “Elenbecestat, a BACE inhibitor: results from a Phase 2 study in subjects with mild cognitive impairment and mild-to-moderate dementia due to Alzheimer’s disease.” Poster P4-389, Alzheimer’s Association International Conference, July 22-26, 2018, Chicago, IL, USA. Similarly, it has been found that subjects having a baseline florbetapir amyloid PET SUVr levels below 1.2 do not exhibit enough cognitive decline to be detectable, whereas subjects having SUVr levels above 1.6 appear to correlate with a plateau effect in which amyloid level has reached a saturation level and treatment does not result in a change of cognitive measures. See Dhadda, S. et al., “Baseline florbetapir amyloid PET standard update value ratio (SUVr) can predict clinical progression in prodromal Alzheimer’s disease (pAD).” Poster P4-291, Alzheimer’s Association International Conference, July 22- 26, 2018, Chicago, IL, USA. “Early AD” or “early Alzheimer’s disease,” as used herein, is a continuum of AD severity from mild cognitive impairment due to AD – intermediate likelihood to mild Alzheimer’s disease dementia. Subjects with early AD include subjects with mild Alzheimer’s disease dementia as defined herein and subjects with mild cognitive impairment Attorney Docket Number 08061.0063-00304 (MCI) due to AD – intermediate likelihood as defined herein. In some embodiments, subjects with early AD have MMSE scores of 22 to 30 and Clinical Dementia Rating (CDR) global range 0.5 to 1.0. Other methods for detecting early AD disease may employ the tests and assays specified below, including the National Institute of Aging-Alzheimer’s Association (NIA-AA) core clinical criteria for probable Alzheimer’s disease dementia in McKhann, G.M. et al., “The diagnosis of dementia due to Alzheimer’s disease: Recommendations from the National Institute on Aging – Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease.” Alzheimer Dement.2011; 7:263-9. Other methods include CDR-SB, ADCOMS Composite Clinical Score, the Mini-Mental State Examination, ADAS-Cog, ADAS MCI-ADL, modified iADRS, Wechsler Memory Scale-IV Logical Memory (subscale) I (WMS-IV LMI), and Wechsler Memory Scale-IV Logical Memory (subscale) II (WMS-IV LMII). In some embodiments, a subject with early AD has evidence of elevated amyloid in the brain or a positive amyloid load. In some embodiments, elevated amyloid in the brain or a positive amyloid load is indicated and / or confirmed by PET assessment. In some embodiments, elevated amyloid in the brain or a positive amyloid load is indicated and / or confirmed by a CSF assessment of markers such as Aβ1-42 (e.g., a soluble CSF biomarker analysis). In some embodiments, elevated amyloid in the brain or a positive amyloid load is indicated and / or confirmed by measuring the level of p-tau181. In some embodiments, elevated amyloid in the brain or a positive amyloid load is indicated and / or confirmed by an MRI. In some embodiments, elevated amyloid in the brain or a positive amyloid load is indicated by retinal amyloid accumulation. In some embodiments, more than one assessment method is used. “Amyloid” refers to fibers that are unbranched, usually extracellular, and found in vivo; in addition, the fibers bind the dye Congo Red and then show green birefringence when viewed between crossed polarizers. Amyloid-forming proteins have been identified and associated with serious diseases, including amyloid-β peptide (Aβ) with Alzheimer’s disease (AD), islet amyloid polypeptide (IAPP) with diabetes type 2, and prion protein (PrP) with the spongiform encephalopathies. As used herein, “amyloid,” “brain amyloid,” and “amyloid-β peptide (Aβ)” are used interchangeably. Aβ exists in various conformational states: monomers, oligomers (e.g., different forms of Aβ oligomers such as dimers, trimers, tetramers, pentamers, hexamers, nonamers, dodecamers), a paranucleus (e.g., a partially- folded monomer that forms a nucleus for fibril elongation), protofibrils (e.g., soluble, pre- fibrillar intermediates), and insoluble fibrils (plaques). Protofibrils are formed as intermediate species when Aβ monomers aggregate into insoluble fibrils, and various species of soluble Attorney Docket Number 08061.0063-00304 protofibrils have been implicated in AD pathogenesis (Hampel et al., Mol Psychiatry, 2021: 26, 5481–550). Aβ peptides generally exist in a dynamic continuum of conformational states such that species tend to progress from monomeric Aβ, to soluble Aβ assemblies that include a range of low molecular weight oligomers to higher molecular weight protofibrils, and finally to insoluble fibrils (plaques). In some embodiments, the subject has “elevated amyloid” or “intermediate amyloid.” As one of ordinary skill in the art will recognize, amyloid levels from amyloid PET can be reported using the Centiloid method in “centiloid” units (CL). (Klunk WE et al. The Centiloid Project: standardizing quantitative amyloid plaque estimation by PET. Alzheimer’s Dement.2015; 11:1–15 e1–4). The Centiloid method measures a tracer on a scale of 0 CL to 100 CL, where 0 is deemed the anchor-point and represents the mean in young healthy controls and 100 CL represents the mean amyloid burden present in subjects with mild to moderate severity dementia due to AD. (Id.) As is known to one of ordinary skill in the art, centiloid thresholds may vary, for example may be refined, based on new or additional scientific information. (See, e.g., http: / / www.gaain.org / centiloid-project.) An elevated level of amyloid can be set relative to a baseline threshold in a healthy control determined according to methods known to a person of ordinary skill in the art (POSA). For example, a centiloid value of 32.5 can be used as a threshold value for “elevated amyloid,” and an “intermediate amyloid” level refers to an Aβ amyloid PET in the range of 20-32.5 CL (e.g., 30 CL). In another example, a centiloid value of 40 can be used as a threshold value for “elevated amyloid,” and an “intermediate amyloid” level refers to an Aβ amyloid PET in the range of 20-40 CL. “Tau” refers to tau proteins, which belong to the family of microtubule-associated proteins (MAPs), and are mainly expressed in neurons and found in the axons and dendrites. Tau proteins play an important role in the assembly of tubulin monomers into microtubules to constitute the cytoskeleton and serve as tracks for axonal transport. Tau proteins are translated from a single gene located on chromosome 17, with alternative mRNA splicing leading to the formation of 6 different central nervous system tau isoforms, of which 5 are found in the human adult brain. The isoforms differ, having either 3 (Rl, R3, and R4) or 4 (R1-R4) repeat-regions in the carboxy (C)-terminal part and variable occurrence of microtubule binding region (MTBR). The amino (N)-terminal domain, which establishes links between microtubules and other parts of the cytoskeleton, or the plasma membrane, has a variable occurrence of 0, 1, or 2 inserts of 29 amino acids. Attorney Docket Number 08061.0063-00304 “Tau pathology” refers to pathological forms of tau, such as intracellular fibrillary tangles and components thereof, which are described in Alzheimer’s disease (AD) and other neurodegenerative disorders, referred to as tauopathies. Aggregation of hyperphosphorylated tau into insoluble paired helical filaments (PHF) that accumulate in neurons to form neurofibrillary tangles (NFTs) are hallmarks of tau pathology. In AD, NFTs occur in a neuroanatomically characteristic pattern of increasing severity, generally defined according to the Braak stages 1 to 6, which correlate well with progressive neuronal loss and clinical decline. Extracellular tau seeds are also a pathological form of tau. Some tau seeds contain the tau MTBR. Subjects with “mild Alzheimer’s disease dementia,” or “mild AD dementia” as used herein, are subjects meeting the National Institute of Aging-Alzheimer’s Association (NIA-AA) core clinical criteria for probable Alzheimer’s disease dementia in McKhann, G.M. et al., “The diagnosis of dementia due to Alzheimer’s disease: Recommendations from the National Institute on Aging – Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease.” Alzheimer Dement.2011; 7:263-9. Also included herein are subjects who have a CDR score of 0.5 to 1.0 and a Memory Box score of 0.5 or greater at screening and baseline and subjects that exhibit change in the score on the Wechsler Memory Scale-Revised Logical Memory subscale II (WMS-R LM II). Subjects with “MCI due to AD – intermediate likelihood,” as used herein are those identified as such in accordance with the NIA-AA core clinical criteria for mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood (see McKhann supra). For example, a subject may be symptomatic but not demented, with evidence of brain amyloid pathology making them less heterogeneous and more similar to mild Alzheimer’s disease dementia subjects in cognitive and functional decline as measured by the ADCOMS Composite Clinical Score defined herein. Also included are subjects who have a CDR score of 0.5 and a Memory Box score of 0.5 or greater at screening and baseline. Furthermore, subjects who report a history of subjective memory decline with gradual onset and slow progression over the last 1 year before screening, which is corroborated by an informant, are also included herein. Memory decline and / or episodic memory impairment can be assessed in a subject by change in the score on the Wechsler Memory Scale-Revised Logical Memory subscale II (WMS-R LM II). As used herein, a “control subject”, “untreated AD subject”, or an “untreated control subject” is a subject that is not being treated or has been treated for Alzheimer’s disease. In some embodiments, a control subject has Alzheimer’s disease. In some Attorney Docket Number 08061.0063-00304 embodiments, the control subject has early Alzheimer’s disease, or pre-Alzheimer’s disease. In some embodiments, the control subject has Alzheimer’s disease and is not treated with an anti-Aβ protofibril antibody. The terms “patient” and “subject” are used interchangeably. As used herein, “MMSE” refers to the Mini-Mental State Examination, a cognitive instrument commonly used for screening purposes, but also often measured longitudinally in AD clinical trials having a 30 point scale with higher scores indicating less impairment and lower scores indicating more impairment, ranging from 0 (most impaired) to 30 (no impairment). In some embodiments, seven items measuring orientation to time and place, registration, recall, attention, language, and drawing may be assessed as part of the MMSE score. (Folstein, M.F. et al., “Mini-mental state. A practical method for grading the cognitive state of patients for the clinician.” J. Psychiatr. Res.1975;12:189-98.) As used herein, “ADAS-Cog” refers to Alzheimer’s Disease Assessment Scale- Cognitive. The ADAS-Cog is a widely used cognitive scale in Alzheimer's disease trials having a structured scale that evaluates memory (word recall, delayed word recall, and word recognition), reasoning (following commands), language (naming, comprehension), orientation, ideational praxis (placing letter in envelope) and constructional praxis (copying geometric designs). (Rosen, W.G. et al., “A new rating scale for Alzheimer’s disease.” Am. J. Psychiatry 1984; 141:1356-64.) Ratings of spoken language, language comprehension, word finding difficulty, ability to remember test instructions, maze, and number cancellation may also be obtained. In some embodiments, ADAS-Cog refers to the use of the Alzheimer Disease Assessment Scale-Cognitive Subscale14 (ADAS-Cog14). In some embodiments, a modified version may be used herein and is scored from 0 to 90 points with a score of 0 indicating no impairment, and a score of 90 indicating maximum impairment. In some embodiments, the ADAS–Cog14 tasks include memory (word recall, delayed word recall, and word recognition), reasoning (following commands), language (naming, comprehension), orientation, ideational praxis (placing letter in envelope), constructional praxis (copying geometric designs), spoken language, language comprehension, word finding difficulty, ability to remember test instructions, maze, and number cancellation (Rosen et al, 1984). As used herein, “CDR-SB” refers to clinical dementia rating - sum of boxes. The CDR is a clinical scale that describes 5 degrees of impairment in performance on each of 6 categories of function including memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. (Berg, L. et al., “Mild senile dementia of the Alzheimer type: 2. Longitudinal assessment.” Ann. Neurol.1988; 23:477- Attorney Docket Number 08061.0063-00304 84.) A sum of boxes score provides a measure of change where each category has a maximum possible score of 3 points and the total score is a sum of the category scores giving a total possible score of 0 to 18 with higher scores indicating more impairment. As used herein, “CDR global”, “global CDR” score and “global rating of dementia CDR” score is used interchangeably. As used herein, CDR global score is a rating of the degree of impairment obtained on each of the 6 categories of function from the 6 categories of the CDR scale and is synthesized into 1 global rating of dementia CDR score, (ranging from 0 to 3) where 0 indicates no cognitive impairment, 0.5 indicates mild cognitive impairment, and 1-3 indicates mild, moderate, severe dementia respectively. The global CDR score may be used as a clinical measure of severity of dementia. In some embodiments, a global CDR score may be used to determine if a patient has progressed or maintained a stage of AD, e.g., a higher score on a subsequent evaluation indicating progression of AD, e.g., an unchanged score indicating no progression of AD. As used herein, “ADCOMS” refers to Alzheimer’s Disease Composite Score, a composite clinical score based on an analysis of four ADAS-Cog items (delayed word recall, orientation, word recognition, and word finding difficulty), two Mini Mental State Examination (MMSE) items (orientation to time, and drawing), and all six CDR-SB items (personal care, community affairs, home and hobbies, memory, orientation, and judgment and problem solving), as discussed in the Examples and in Wang, J. et al., “ADCOMS: a composite clinical outcome for prodromal Alzheimer’s disease trials.” J. Neurol. Neurosurg. Psychiatry.2016; 87:993-999. ADCOMS was developed to be particularly sensitive to disease progression during early stages of AD (i.e., preclinical AD or early AD). In some embodiments, ADCOMS can be calculated using the following formula: ^ଶ ^ ^^^^ ^^^ ^ ^^^ ^^ ^^^ ^^ ^^^ where ^^^^ ^^^, ^^^^ ^^^ and items from ADAS- cog, reversed MMSE scores, and CDR-SB, respectively (Wang, J. et al., “ADCOMS: a composite clinical outcome for prodromal Alzheimer’s disease trials). ADCOMS is particularly sensitive to disease progression during early stages of AD, i.e., prodromal and mild AD. As used herein, “ADCS MCI-ADL” refers to the Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale for Mild Cognitive Impairment (ADCS MCI-ADL). The ADCS MCI-ADL is a clinical scale that assesses the competence level of a patient at six Attorney Docket Number 08061.0063-00304 basic activities of daily living. Additional examples are discussed in Kreutzer J.S., DeLuca J., Caplan B. (eds) Encyclopedia of Clinical Neuropsychology. Springer, New York, NY. As used herein, “modified iADRS” or “iADRS” refers to a composite tool that combines scores from the ADAS Cog14 (all items) and the ADCS MCI-ADL (all items). The modified iADRS score can be used to evaluate disease progression: Modified iADRS score = [-1(ADAS-cog14) +90] + ADCS MCI-ADL. As used herein, “ApoE4-positive” subjects and “ApoE4 carriers” refer to subjects who harbor the ε4 variant of the apolipoprotein (APOE) gene. The ε4 variant is one of several major alleles of the apolipoprotein gene. The gene is generally responsible for metabolism of fats. It has been found that carriers of the apolipoprotein ε4 show significantly greater rates of amyloid retention when compared to non-carriers. (Drzezga, A. et al, “Effect of APOE genotype on amyloid plaque load and gray matter volume in Alzheimer disease.” Neurology. 2009; 72:1487-94.) In some embodiments, a subject treated herein is a heterozygous carrier of the apolipoprotein E ε4 gene allele. In some embodiments, the subject is a homozygous carrier of the apolipoprotein E ε4 gene allele. The terms “ApoE4-negative” and “ApoE4 non- carriers” are used interchangeably. As used herein, whether an early AD subject is “amyloid positive” or “amyloid negative” may be determined based on whether the subject has a positive amyloid load. In some embodiments, a subject is determined to be amyloid-positive or amyloid-negative as indicated by longitudinal positron emission tomography (PET) assessment of an imaging agent uptake into the brain, e.g., an amyloid imaging agent or a tau imaging agent. In some embodiments, a subject is determined to be amyloid-positive or amyloid-negative by evaluation of a tau PET imaging assessment. In some embodiments, the subject is “amyloid negative” if PET SUVr negativity is below a threshold determined for an amyloid PET tracer. In some embodiments, the amyloid PET tracer may be florbetaben (e.g., 18F-Florbetaben (Neuraceq®)), florbetapir (e.g., 18F-Florbetapir (Amyvid®)), and / or flutametamol (e.g., 18F- Flutemetamol (Vizamyl®)). In some embodiments, the threshold for PET SUVr for an amyloid PET tracer is about 1.17, and a measurement below this threshold may indicate that the subject is “amyloid negative.” In some embodiments, the florbetapir amyloid PET SUVr threshold is about 1.17. In some embodiments, the florbetaben amyloid PET SUVr threshold is about 1.17. In some embodiments, the flutemetamol amyloid PET SUVr threshold is about 1.17. In some embodiments, a subject is determined to be amyloid-positive or amyloid- negative by evaluation of the level of a biomarker in a sample (e.g., a Aβ42 / 40 ratio) from a subject, alone or in combination with another method such as PET measurement of brain Attorney Docket Number 08061.0063-00304 amyloid. In some embodiments, a subject is “amyloid negative” if the Aβ42 / 40 ratio in a sample is at or about above 0.092-0.094 e.g., at about 0.092. In some embodiments, a subject is “amyloid negative” if the Aβ42 / 40 ratio in a sample is above 0.092. In some embodiments, a subject is determined to be amyloid-positive or amyloid-negative by a CSF assessment of the presence of amyloid pathology using assessments of markers such as p-tau181, alone or in combination with another method such as PET measurement of brain amyloid. In some embodiments, a qualitative visual read of PET scans may be used to determine amyloid positive and amyloid negative by categorizing subjects as having either “normal” or “abnormal” uptake on the basis of the PET image pattern. Readers will have been trained and certified to recognize brain PET images with abnormal or normal patterns of uptake, or the detection of amyloid is done through a semi-quantitative or quantitative approach. In some embodiments, a threshold will be set for quantitatively determining from a biomarker (e.g., serum or CSF) and / or PET scan whether an Aβ brain load indicates a subject is amyloid-positive or negative. In some embodiments, a subject is determined to be amyloid- positive or amyloid-negative by an imaging method. An imaging method may be used to determine, calculate, or predict whether a subject is amyloid-positive or negative, even when the imaging method is not used to visualize amyloid directly. In some embodiments, the method uses MRI), and / or combines MRI and other imaging modalities such as PET. In some embodiments, a subject is determined to be amyloid-positive or amyloid-negative by retinal amyloid accumulation. In some embodiments, a subject is determined to be amyloid-positive or amyloid-negative by behavioral / cognitive phenotypes. As would be understood by one of ordinary skill in the art, digital, computerized, and / or conventional (e.g., pen and paper) cognitive tests may be used to detect early cognitive changes that may signal mild cognitive impairment and / or a risk for developing dementia, and thus may be used to identify subject in need of treatment as disclosed herein. Such tests, for example, may screen for cognitive impairment, and potentially identify individuals with MCI. Tests may use artificial intelligence to analyze cognitive test results to determine whether a case of mild cognitive impairment will escalate into Alzheimer’s within a year. Diagnosing the condition early, before symptoms have begun to appear, may be used to assist physicians identify subjects in need of treatment as disclosed herein sooner, potentially delaying onset or lessening the severity of the neurodegenerative disease. As used herein, the term “treat” refers to any administration or application of a therapeutic agent for a disease or disorder in a subject, and includes inhibiting the disease, slowing progression of the disease, delaying progression, arresting its development, reversing Attorney Docket Number 08061.0063-00304 progression of disease (e.g., reversing build up of Aβ fibrils), preventing the onset or development of the disease, relieving or ameliorating one or more symptoms or underlying condition(s) of the disease, curing the disease, improving one or more clinical metrics, or preventing reoccurrence of one or more symptoms of the disease. In some embodiments, treatment of AD in a subject comprises an administration, e.g., an intravenous infusion, of an anti-amyloid β (Aβ) protofibril antibody. In some embodiments, treatment of AD in a subject comprises a therapeutically effective dose by administration, e.g., an intravenous infusion, of an anti-amyloid β (Aβ) protofibril antibody. As used herein, the term “infusion” refers to an active administration of one or more agents with an infusion time of, for example, approximately 60 minutes. In some embodiments, an anti-amyloid β (Aβ) protofibril antibody, described herein is systemically administered to a human subject via infusion. In some embodiments, an anti-amyloid β (Aβ) protofibril antibody is alternatively administered to the human subject, e.g., by subcutaneous injection. In some embodiments, the subcutaneous injection is a weekly injection. In some embodiments, the subcutaneous injection is a biweekly injection. In some embodiments, an anti-amyloid β (Aβ) protofibril antibody is administered to the human subject by intravenous infusion. In some embodiments, the subject is administered a maintenance dose of a treatment. As used herein, the term “maintenance dose” refers to a dosage administered to a subject to maintain the desired therapeutic effect. In some embodiments, the maintenance dose is administered weekly, every two weeks, monthly, every two months, or every three months (quarterly) or every 24 weeks (every six months or semi-annually). In some embodiments, the maintenance dose comprises an anti-Aβ protofibril antibody. In some embodiments, the maintenance dose is administered as an intravenous infusion. In some embodiments, the intravenous infusion is a 10 mg / kg dose of lecanemab administered monthly. In some embodiments, the maintenance dose is administered subcutaneously, orally, or nasally. In some embodiments, the maintenance dose is administered subcutaneously. In some embodiments, the maintenance dose is administered as a subcutaneous injection. In some embodiments, the maintenance dose is administered as a weekly, subcutaneous injection. In some embodiments, the maintenance dose is administered as a biweekly, subcutaneous injection. In some embodiments, the maintenance dose is administered as a monthly, subcutaneous injection. In some embodiments, the maintenance dose is administered as a quarterly, subcutaneous injection. In some embodiments, the maintenance dose is administered weekly or less frequently, e.g., every two weeks Attorney Docket Number 08061.0063-00304 (biweekly), every four weeks, monthly, every six weeks, every eight weeks (2 months), every three months (quarterly) or every six monthly (semi-annually). In some embodiments, the maintenance dose is administered as a biweekly, subcutaneous injection of 500 mg, 360 mg, or 250 mg. In some embodiments, the maintenance dose is administered as a biweekly, subcutaneous injection of 500 mg comprising two concurrent, e.g., sequential, injections of 250 mg (e.g., 2 x 1.25 mL of 400 mg / 2 mL) of the subcutaneous formulation. In some embodiments, the subcutaneous dose is administered in a single injection of 360 mg (e.g., 1 x 1.8 mL of 400 mg / 2 mL) of the subcutaneous formulation. In some embodiments, the subcutaneous dose of 250 mg is administered in a single injection of 250 mg (e.g., 1 x 1.25 mL of 400 mg / 2 mL) of the subcutaneous formulation. In some embodiments, the subcutaneous dose is administered by a vial-syringe method or by an auto-injector (AI). In some embodiments, a subcutaneous dose of 500 mg, 360 mg, or 250 mg is administered using an auto-injector. In some embodiments, the maintenance dose is administered once or multiple times. In some embodiments, the maintenance dose is administered at a lower dose than during an earlier course of treatment and / or is administered less frequently than during the earlier course of treatment. In some embodiments, after switching to a maintenance dose, a subject’s biomarker levels may indicate increasing levels of amyloid in the brain. In some embodiments, after switching to a maintenance dose, a subject’s biomarker levels may begin to worsen, e.g. an increasing plasma Aβ42 / 40 ratio, indicating increasing levels of amyloid in the brain. In some embodiments, a subject on a maintenance dose may have a decrease in the Aβ42 / 40 ratio. In some embodiments, a subject is put on a maintenance dose chosen such that the subject may have a decrease in the Aβ42 / 40 ratio but the Aβ42 / 40 ratio may remain above the threshold for amyloid positivity, e.g. for at least one year (e.g., at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 years). In some embodiments, after switching to a maintenance dose, levels of a subject’s biomarker, e.g., MTBR-tau243 from a biofluid sample (e.g., CSF or blood) may increase. In some embodiments, after switching to a maintenance dose, a subject’s biomarker levels may begin to worsen, e.g. an increasing CSF MTBR-tau243. In some embodiments, a subject is put on a maintenance dose chosen such that the subject may have a decrease in the MTBR- tau243 concentration and maintain the concentration at a level comparable to a healthy control for at least one year (e.g., at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 years). Attorney Docket Number 08061.0063-00304 In some embodiments, after switching to a maintenance dose, a subject’s biomarker levels, e.g. a MTBR-tau243 concentration or a tau PET level, may begin to increase or a rate of increase may increase. In some embodiments, such a subject may be moved back to a treatment regimen. In some embodiments, a subject may remain on a maintenance dose, e.g., if the increase remains below a tau PET level or rate of increase seen in a control subject who has AD but does not receive an anti-Aβ protofibril antibody. As used herein, the term “prevent” refers to obtaining beneficial or desired results including, but not limited to, prophylactic benefit. For prophylactic benefit, the composition may be administered to a subject at risk of developing Alzheimer’s disease, to a subject having one or more preclinical symptoms but not clinical symptoms of Alzheimer’s disease, or to a subject reporting one or more of the physiological symptoms of Alzheimer’s disease, even though a clinical diagnosis of having Alzheimer’s has not been made. As used herein “prevention” may further include therapeutic benefit, by which is meant eradication or amelioration of the underlying condition being treated or of one or more of the physiological symptoms associated therewith. As used herein, the term “ARIA” refers to amyloid-related imaging abnormality as evaluated using MRI. In some embodiments, ARIA includes amyloid related imaging abnormality edema / effusion (ARIA-E). In some embodiments, ARIA includes amyloid related imaging abnormality hemorrhage (ARIA-H). In some embodiments, subjects with ARIA experience headache, confusion, and / or seizure and these may be used to identify a subject with ARIA or to indicate further evaluation for ARIA. In some embodiments, ARIA is evaluated at specified intervals during treatment. In some embodiments, ARIA is evaluated when the subject experiences symptoms of ARIA. In some embodiments, maximum serum concentration (Cmax) of anti-Aβ protofibril antibody can be used as a predictor of the risk of ARIA-E. In some embodiments, the use of a subcutaneous formulation may provide a reduced risk of ARIA-E (e.g., due to a lower Cmax) compared to an IV administration. As used herein, the term “clinical decline” refers to a worsening of one or more clinical symptoms of AD. Methods for measuring clinical decline may employ the tests and assays specified herein. In some embodiments, clinical decline is determined by a worsening of ADCOMS. In some embodiments, clinical decline is determined by a worsening of MMSE. In some embodiments, clinical decline is determined by a worsening of ADAS-Cog. In some embodiments, clinical decline is determined by a worsening of FAQ. In some embodiments, clinical decline is determined by a worsening of CDR-SB. In some embodiments, clinical decline is determined by a worsening of Wechsler Memory Scale-IV Attorney Docket Number 08061.0063-00304 Logical Memory (subscale) I and / or (subscale) II. In some embodiments, clinical decline is determined by a worsening of CDR score. In some embodiments, clinical decline refers to a worsening in one or more biomarkers of AD or brain measurement (e.g., by PET or MRI), e.g., of brain atrophy and / or amyloid accumulation. As used herein, the term “blood sample” or “blood” refers to a sample of blood, including serum and / or blood plasma from a human subject. In some embodiments, blood will be collected from subjects to evaluate potential biomarkers of AD that may include amyloid fragments and isoforms, tau, and other protein biomarkers (e.g., anti-microbial peptides, neurofilament light chain or NfL) for association with AD diagnosis, amyloid or tau load, or disease modification. In some embodiments, subjects are required to fast if possible before collection at Week 96 and Week 216. In other embodiments and / or at other time points, subjects do not require fasting. Pre-AD biomarker levels that may suggest the development of Alzheimer’s disease include, but are not limited to, brain amyloid level, cerebrospinal fluid level of Aβ1-42, cerebrospinal fluid level of total tau, cerebrospinal fluid level of neurogranin, and cerebrospinal fluid level of neurofilament light chain (NfL).

[0002] Attorney Docket Number 08061.0063-00304 SEQUENCE TABLES Table 1. Amino acid sequences of monoclonal antibody (mAb) CDRs mAb IgG chain SEQ ID NO Amino acid sequence BAN2401 HCDR1 1 SFGMH Table 2. Amino acid sequences of mAb variable regions mAb IgG chain SEQ ID NO Amino acid sequence F L S I V K

[0003] Attorney Docket Number 08061.0063-00304 Table 3. Amino acid sequences of mAb heavy and light chains mAb IgG chain SEQ ID NO Amino acid sequence BAN2401 Heavy chain 9 EVQLVESGGGLVQPGGSLRLSCSASGF

[0004] Attorney Docket Number 08061.0063-00304 Table 4. Amino acid sequences of mAb constant regions mAb IgG chain Class SEQ ID NO Amino acid sequence T V P H L K V V N A T K R Table 5. Amino acid sequences of Amyloid β Amyloid β SEQ ID NO Amino acid sequence S S Table 6. Amino acid sequences of E2814 CDRs mAb IgG chain SEQ ID NO Amino acid sequence Attorney Docket Number 08061.0063-00304 E2814 HCDR2 16 DIYPGSSISNYNEKFKS Heavy Chain HCDR3 17 EDGYDAWFAY abe . mno acd sequences o 8 varabe regons mAb IgG chain SEQ ID NO Amino acid sequence Y G I V P

[0005] Attorney Docket Number 08061.0063-00304 Table 8. Amino acid sequences of E2814 constant regions mAb IgG chain Class SEQ ID NO Amino acid sequence E2814 H h i I G1 23 ASTKGPSVFPLAPSSKSTSGGT V P H L K V N A T K R

[0006] Attorney Docket Number 08061.0063-00304 Table 9. Amino acid sequence of Tau SEQ ID NO Amino acid sequence T 25 MAEPR EFEVMEDHAGTYGLGDRKD GGYTMH D EGDT T K P P H S

[0007] Attorney Docket Number 08061.0063-00304 Table 10. Antimicrobial Peptides Peptide Fold- Cohen p- q Mapped to Peptide SEQ AMP_ID UniprotID change sD value Human sequence ID Protein NO P 3 2 4 P 3 2 4 2 4 2 4 P 3 P 3 Attorney Docket Number 08061.0063-00304 Peptide Fold- Cohen p- q Mapped to Peptide SEQ AMP_ID UniprotID change sD value Human sequence ID Protein NO P - - 5 P 4 2 4 2 4 P 3 P 3 P 4 Attorney Docket Number 08061.0063-00304 Peptide Fold- Cohen p- q Mapped to Peptide SEQ AMP_ID UniprotID change sD value Human sequence ID Protein NO P 3

[0008] Attorney Docket Number 08061.0063-00304 The present disclosure is further illustrated by the following examples that should not be construed as limiting. The contents of all references, patents, and published patent applications cited throughout this application, as well as the figures, are incorporated herein by reference in their entirety for all purposes. EXAMPLES Example 1: Identification of Antimicrobial Peptides (AMPs) Figure 1 shows the cohort demographics (Fig.1A) and cohort study methodology Fig.1B). CSF data was obtained from patients recruited at several memory clinics in western Sweden. All subjects were cognitively impaired. Mass spectrometry (MS) data obtained from a published study (PRIDE archive PXD016278; Bader et al., Mol Syst Biol, 2020;16(6):e9356) was used to compare peptides in the CSF from subjects with cognitively impaired A ^+ (AD) and A ^- (non-AD) individuals. Subjects with AD were classified based on t-tau levels above 400 ng / L, Aβ1-42 levels below 550 ng / L, and a Aβ1-42 / Aβ1-40 ratio below 0.065. The t-tau criterion and at least one of the Aβ criteria had to be met for a patient to be classified as AD. MS files were analyzed using a novel platform integrating a de novo-based- workflow with a custom human protein database integrating AMP sequences to enable the identification of antimicrobial peptides in CSF samples. Non-tryptic, semi-tryptic, and fully- tryptic peptides were selected. When AMPs are generated, they may not be fully-tryptic peptides (e.g., with K and R amino acid resides at their ends, resulting from the sites where trypsin cuts). Accordingly, selection strategies for non-tryptic and semi-tryptic peptides may enable selection of diverse peptides, including those which do not have K and R amino acids at the ends. Figure 2 shows the workflow used to obtain 24 AMPs. Starting with 39,447 peptides from de novo analysis, peptides mapped to contaminant database were removed. From the remaining 36,409 peptides, non-AMP peptides were removed, leaving 815 AMPs. Peptides with more than 75% missing data were excluded, leaving 547 AMPs. Peptides with zero variation were removed, leaving 485 AMPs. A PTM adjustment was performed, leaving 320 AMPs. Of these, 24 AMPs were significant at q<0.2. The sequences of the 24 AMPs are listed in Table 10, together with the fold change of each AMP, p, Cohen’s D, and q values. The UniProt ID refers to the protein to which the peptides map (e.g., proteins from which the Attorney Docket Number 08061.0063-00304 peptides are produced) and the AMP_ID refers to the ID number in the public AMP databases (dbAMP, https: / / awi.cuhk.edu.cn / dbAMP / and UDAMP, https: / / aps.unmc.edu / ). Peptide raw peak area intensities were quantile normalized and log2 transformed to reduce technical variation and ensure distribution symmetry. Differentially expressed peptides were identified via analysis of covariance after adjusting for age and gender, with the significance criteria set at 20% false discovery rate. Figure 3 is a volcano plot using 320 CSF peptides in cognitively impaired subjects. 24 / 320 CSF AMP peptides were differentially regulated in subjects that are Aβ+ (AD) vs Aβ- (non-AD) comparisons (q <0.2). Figure 4 shows a heat map showing 24 significantly altered AMPs (q<0.2) in subjects that are Aβ+ (AD) and Aβ- (non-AD) dementia. Figure 5 shows a box plot showing increased expression of antimicrobial peptides from Clusterin (Fig.5A) and Chromogranin A (Fig.5B) proteins in CSF of Aβ-driven dementia. A Multiscale Embedded Gene Co-expression Network Analysis (MEGENA) was used to identify AMPs with the potential to regulate the molecular changes in AD. Figure 6 shows MEGENA data-driven peptide co-expression network consisted of 642 modules (Fig.6A). CMGA peptide represented a hub in C1_16 and c1_179 modules and exhibited high correlation with a dementia-linked neurosecretory protein VGF (Fig.6B). Gene Ontology analysis of c1_16 module proteins showed enrichment of many neurodegeneration associated pathways (Fig.6C). The top enriched pathways in the c1_16 module were cell adhesion, system development, nervous system development, regulation of nervous system development, and neurogenesis.

Claims

Attorney Docket Number 08061.0063-00304 CLAIMS 1. A method of selecting a subject for a treatment with an Alzheimer’s disease (AD) therapy, comprising: a) obtaining a measurement of a level of at least one antimicrobial peptide (AMP) in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) selecting the subject for treatment if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

2. A method of selecting a subject for a treatment with an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) selecting the subject for treatment if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

3. The method of claim 2, wherein the AMP is a peptide listed in Table 10.

4. The method of any one of claims 1-3, wherein the subject has, is suspected of having, or is at risk for developing Alzheimer’s disease (AD).

5. The method of claim 4, wherein the subject has early AD or mild to moderate AD.

6. The method of any one of claims 1-5, wherein the subject is selected for treatment if the AMP level from the subject is increased as compared to the control.Attorney Docket Number 08061.0063-00304 7. The method of any one of claims 1-5, wherein the subject is selected for treatment if the AMP level from the subject is decreased as compared to the control.

8. A method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level as compared to first AMP level is an indicator of treatment efficacy, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

9. A method of monitoring treatment efficacy in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin- ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first AMP level to the second AMP level, wherein a change in the second AMP level as compared to first AMP level is an indicator of treatment efficacy, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

10. The method of claim 9, wherein the AMP is a peptide listed in Table 10.

11. The method of any one of claims 8-10, wherein a decrease in the second AMP level as compared to first AMP level indicates an effective treatment.Attorney Docket Number 08061.0063-00304 12. The method of any one of claims 8-10, wherein a lack of a decrease in the second AMP level as compared to first AMP level indicates a non-effective treatment.

13. The method of claim 3, wherein a decrease in the second AMP level as compared to first AMP level indicates a non-effective treatment.

14. The method of claim 3, wherein a lack of a decrease in the second AMP level as compared to first AMP level indicates an effective treatment.

15. A method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) comparing the level of at least one AMP to a control sample, e.g., an AMP level concentration in an individual who does not have Alzheimer’s disease (AD); and c) adjusting the treatment regimen if the level of at least one AMP is different compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), e.g., by changing the size of the dose, the frequency of administration, and / or the route of administration of the anti-Aβ protofibril antibody, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

16. A method of adjusting a treatment regimen in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) comparing the level of at least one AMP to a control sample, e.g., an AMP level concentration in an individual who does not have Alzheimer’s disease (AD); andAttorney Docket Number 08061.0063-00304 c) adjusting the treatment regimen if the level of at least one AMP is different compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), e.g., by changing the size of the dose, the frequency of administration, and / or the route of administration of the anti-Aβ protofibril antibody, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

17. The method of claim 16, wherein the AMP is a peptide listed in Table 10.

18. The method of any one of claims 15-17, wherein the treatment regimen is adjusted if the AMP level is higher than a control.

19. The method of any one of claims 15-17, wherein the treatment regimen is adjusted if the AMP level is lower than a control.

20. A method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab).

21. A method of detecting a decrease in a brain Aβ level in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-Attorney Docket Number 08061.0063-00304 ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody.

22. The method of claim 21, wherein the AMP is a peptide listed in Table 10.

23. The method of any one of claims 20-22, wherein a decreased AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject.

24. The method of any one of claims 20-22, wherein an increased AMP level in the second sample relative to the first sample indicates a decrease of a brain Aβ level in the subject.

25. A method of detecting a decrease in a brain tau level (e.g., a reduction in tau tangles) in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is selected from any of those listed in Table 10; b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).Attorney Docket Number 08061.0063-00304 26. A method of detecting a decrease in a brain tau level (e.g., a reduction in tau tangles) in a subject receiving a treatment comprising a therapeutically effective dose of an AD therapy, comprising: a) obtaining a measurement of a first AMP level in a first biofluid sample, e.g., a CSF or blood sample, from the subject prior to the treatment, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin- ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) obtaining a measurement of a second AMP level in a second biofluid sample, e.g., a CSF or blood sample, from the subject during or after the treatment; and c) comparing the first and second AMP levels, wherein an altered AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject; optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

27. The method of claim 26, wherein the AMP is a peptide listed in Table 10.

28. The method of any one of claims 25-27, wherein a decreased AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject.

29. The method of any one of claims 25-27, wherein an increased AMP level in the second sample relative to the first sample indicates a decrease of a brain tau level in the subject.

30. The method of any one of claims 25-29, wherein a decrease of a brain tau level is a decrease in tau tangles.

31. A method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising:Attorney Docket Number 08061.0063-00304 a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the first AMP level is elevated compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level in a biofluid sample, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles, optionally wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3).

32. A method of reducing tau tangles in a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a first AMP level in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); b) administering to the subject a treatment comprising a therapeutically effective dose of an anti-tau protofibril antibody if the first AMP level is elevated compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD); and c) obtaining a measurement of a second AMP level in a biofluid sample, wherein a change in the second AMP level as compared to the first AMP level indicates a reduction in tau tangles,Attorney Docket Number 08061.0063-00304 optionally wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3).

33. A method of treating a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is selected from any of those listed in Table 10; and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

34. A method of treating a subject having, suspected of having, or at risk for developing Alzheimer’s disease (AD), comprising: a) obtaining a measurement of a level of at least one AMP in a biofluid sample, e.g., a CSF or blood sample, from the subject, wherein the AMP is a peptide of a human protein selected from Amyloid-beta precursor protein (A4), Beta-2-microglobulin (B2MG), Clusterin (CLUS), Chromogranin-A (CMGA), Secretogranin-1 (SCG1), Ubiquitin-ribosomal protein eL40 fusion protein (RL40), Ubiquitin-40S ribosomal protein S27A, Polyubiquitin-B (UBB), and Polyubiquitin-C (UBC); and b) administering to the subject a treatment comprising a therapeutically effective dose of an AD therapy if the level of at least one AMP is altered compared to a control sample, e.g., compared to an AMP level in an individual who does not have Alzheimer’s disease (AD), optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).Attorney Docket Number 08061.0063-00304 35. The method of claim 34, wherein the AMP is a peptide listed in Table 10.

36. The method of any one of claims 33-35, wherein the AD therapy is administered if the AMP level is increased compared to the control sample.

37. The method of any one of claims 33-35, wherein the AD therapy is administered if the AMP level is decreased compared to the control sample.

38. The method of any one of claims 33-37, further comprising: a) obtaining a further measurement of the level of at least one AMP (e.g., a further AMP level) in a second biofluid sample, e.g., a CSF or blood sample, from the subject; b) determining that the further AMP level has changed relative to the level of at least one AMP obtained prior to administration of the AD therapy; and c) administering a further therapeutically effective dose of the AD therapy to the subject, optionally wherein the AD therapy is an anti-Aβ protofibril antibody (e.g., lecanemab) or an anti-tau antibody (e.g., E2814).

39. The method of claim 38, wherein the further therapeutically effective dose is administered according to a maintenance dosing regimen.

40. The method of any one of claims 1-38, wherein the treatment comprises administration of a therapeutically effective dose of the AD therapy according to an initiation dosing regimen, optionally after which the subject is switched to a maintenance dosing regimen.

41. The method of claim 40, wherein the subject is switched from an initiation dosing regimen to a maintenance dosing regimen when a further measurement of AMP level in a further biofluid sample, e.g., a CSF or blood sample, from the subject differs from a threshold, e.g., a level seen in a control sample from an individual who does not have AD.

42. The method of claim 41, wherein the subject is switched when the AMP level is below the threshold.Attorney Docket Number 08061.0063-00304 43. The method of claim 41, wherein the subject is switched when the AMP level is above the threshold.

44. The method of any one of claims 1-43, wherein the AMP level is quantified by LC / MS.

45. The method of any one of claims 1-44, wherein the biofluid sample is CSF.

46. The method of any one of claims 1-45, wherein the subject shows a change and / or difference in a measurement of one or more additional biomarkers associated with AD pathology prior to treatment.

47. The method of claim 46, wherein the change and / or difference in the measurement is selected from: a) increased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), b) increased tau in the brain, e.g., as measured by positron emission tomography (PET), c) decreased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and d) decreased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or increased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL).

48. The method of any one of claims 1-45, wherein the subject shows a change and / or difference in a measurement of one or more additional biomarkers associated with AD pathology during and / or after treatment.Attorney Docket Number 08061.0063-00304 49. The method of claim 48, wherein the change and / or difference in the measurement is selected from: a) decreased amyloid in the brain, e.g., as measured by amyloid PET (e.g., a centiloid measure of about 20-40, e.g., a centiloid measure of about 20-32), b) decreased tau in the brain, e.g., as measured by positron emission tomography (PET), c) increased cerebrospinal fluid levels of ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, neurogranin, and / or neurofilament light chain (NfL), and d) increased blood serum or plasma levels of a ratio of Aβ1-42 / 1-40 and / or decreased total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, glial fibrillary acidic protein (GFAP), and / or neurofilament light chain (NfL).

50. The method of any one of claims 1-49, wherein the treatment a) delays clinical decline as determined by ADCOMS; b) delays clinical decline as determined by ADAS MCI-ADL; c) delays clinical decline as determined by modified iADRS; d) delays clinical decline as measured by a CDR-SB; or e) delays clinical decline as measured by an ADAS-Cog.

51. The method of any one of claims 1-50, wherein the subject has a genetic mutation for a dominantly inherited Alzheimer’s disease, e.g., wherein the subject a genetic mutation in at least one of three genes — PSEN1, PSEN2, or APP.

52. The method of claim 51, wherein the subject has a mutation in APP.Attorney Docket Number 08061.0063-00304 53. The method of any one of claims 1-52, wherein the subject has a family history of Alzheimer’s disease, e.g., a history of a family member being diagnosed with Alzheimer’s disease before the age of 60.

54. The method of any one of claims 1-53, wherein the subject is ApoE4-positive.

55. The method of any one of claims 1-54, wherein the subject is 65 to 80 years old.

56. The method of any one of claims 1-55, wherein the subject is 55 to 64 years old and has at least one risk factor chosen from: (i) a first degree relative diagnosed with dementia onset before age 75; (ii) at least one apolipoprotein E4 variant (APOE4) allele; and (iii) elevated brain amyloid according to PET or cerebrospinal fluid (CSF) testing prior to said administration.

57. The method of any one of claims 1-56, wherein the subject is amyloid positive.

58. The method of claim 57, wherein the subject is amyloid positive based on a PET assessment, a CSF assessment of Aβ(1-42), a CSF assessment of total tau, a CSF assessment of phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231), MTBR-tau243, MRI, retinal amyloid accumulation, and / or a blood biomarker assessment (e.g. a plasma Aβ1-42 / 1-40 ratio, total tau, phosphorylated tau (e.g., p-tau181, p-tau205, p-tau217, and / or p-tau231), the ratio of phosphorylated tau / non-phosphorylated tau (e.g., tau181 / np-tau181, tau205 / np-tau205, p- tau217 / np-tau217 and / or tau231 / np-tau231) and / or MTBR-tau243.

59. The method of any one of claims 1-58, wherein the subject has Alzheimer’s disease.

60. The method of any one of claims 1-58, wherein the subject has early Alzheimer’s disease.

61. The method of any one of claims 1-560, wherein the subject has been diagnosed withAttorney Docket Number 08061.0063-00304 a) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood and / or has been diagnosed as having mild Alzheimer’s disease dementia; b) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by National Institute of Aging – Alzheimer’s Association (NIA-AA) core clinical criteria; c) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by a CDR global score of 0.5 and a Memory Box score of 0.5 or greater before treatment; d) mild cognitive impairment due to Alzheimer’s disease – intermediate likelihood by a history of subjective memory decline with gradual onset and slow progression over the last 1 year before treatment, e.g., as corroborated by an informant; e) mild Alzheimer’s disease dementia by the NIA-AA core clinical criteria for probable Alzheimer’s disease dementia; or f) mild Alzheimer’s disease dementia by a CDR score of 0.5 to 1.0 and a Memory Box score of 0.5 or greater before treatment.

62. The method of any one of claims 1-56, wherein the subject is suspected of having AD.

63. The method of any one of claims 1-56, wherein the subject is a subject at risk for developing AD.

64. The method of claim 63, wherein the subject at risk for developing AD has pre- Alzheimer’s disease (pre-AD).

65. The method of claim 63 or 64, wherein the subject does not have cognitive impairment.

66. The method of any one of claims 1-65, wherein the anti-Aβ protofibril antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 1 (HCDR1), SEQ ID NO: 2 (HCDR2), and SEQ ID NO: 3 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 4 (LCDR1), SEQ ID NO: 5 (LCDR2), and SEQ ID NO: 6 (LCDR3).

67. The method of claim 66, wherein the anti-Aβ protofibril antibody is lecanemab.Attorney Docket Number 08061.0063-00304 68. The method of any one of claims 1-65, wherein the anti-tau antibody comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) comprising amino acid sequences of SEQ ID NO: 15 (HCDR1), SEQ ID NO: 16 (HCDR2), and SEQ ID NO: 17 (HCDR3); and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) comprising amino acid sequences of SEQ ID NO: 18 (LCDR1), SEQ ID NO: 19 (LCDR2), and SEQ ID NO: 20 (LCDR3).

69. The method of claim 68, wherein the anti-tau antibody is E2814.

70. The method of any one of claims 1-69, wherein the antimicrobial peptide comprises any one of SEQ ID NOs: 27-50.

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