Plasma Amyloid-β in Relation to Antibodies Against Herpes Simplex Virus, Cytomegalovirus, and Chlamydophila pneumoniae

BACKGROUND: Amyloid-β (Aβ), the key constituent of Alzheimer’s disease (AD) plaques, has antimicrobial properties. OBJECTIVE: To investigate the association between plasma Aβ and antibodies against the AD-related pathogens herpes simplex virus (HSV), cytomegalovirus (CMV), and C. pneumoniae. METHODS: Plasma from 339 AD cases, obtained on average 9.4 years (±4.00) before diagnosis, and their matched controls were analyzed for Aβ(40) and Aβ(42) concentrations with Luminex xMAP technology and INNOBIA plasma Aβ-form assays. Enzyme-linked immunosorbent assays were utilized for analyses of anti-HSV immunoglobulin (Ig) G, anti-HSV1 IgG, anti-HSV2 IgG, anti-CMV IgG, and anti-C. pneumoniae IgG. Follow-up samples were available for 150 of the cases. RESULTS: Presence and levels of anti-HSV1 IgG, anti-HSV2 IgG, anti-CMV IgG, and anti-C. pneumoniae IgG did not correlate with concentrations of Aβ(42) or Aβ(40) in cases or controls. CONCLUSION: Levels of plasma Aβ were not associated with antibodies against different AD-related pathogens.