Plasma Biomarkers of Alzheimer’s Disease in African Americans

BACKGROUND/OBJECTIVE: The aim of this study was to determine if plasma concentrations of 5 surrogate markers of Alzheimer’s disease (AD) pathology and neuroinflammation are associated with disease status in African Americans. METHODS: We evaluated 321 African Americans (159 AD, 162 controls) from the Florida Consortium for African-American Alzheimer’s Disease Studies (FCA(3)DS). Five plasma proteins reflecting AD neuropathology or inflammation (Aβ(42), tau, IL6, IL10, TNFα) were tested for associations with AD, age, sex, APOE and MAPT genotypes, and for pairwise correlations. RESULTS: Plasma tau levels were higher in AD when adjusted for biological and technical covariates. APOE ɛ4 was associated with lower plasma Aβ(42) and tau levels. Older age was associated with higher plasma Aβ(42), tau, and TNFα. Females had lower IL10 levels. Inflammatory proteins had strong pairwise correlations amongst themselves and with Aβ(42). CONCLUSION: We identified effects of demographic and genetic variants on five potential plasma biomarkers in African Americans. Plasma inflammatory biomarkers and Aβ(42) may reflect correlated pathologies and elevated plasma tau may be a biomarker of AD in this population.