Lawrence Berkeley National Laboratory

INTRODUCTION: It is unclear whether the different Alzheimer's disease (AD) progression trajectories of apolipoprotein E (APOE) ɛ4 carriers is reflected by blood phosphorylated tau (p-tau) analytes. METHODS: We assessed longitudinal trajectories in plasma p-tau181, 217, and 231, in amyloid beta-positive (A+) and negative (A-) APOE ɛ4 carriers (E+) or non-carriers (E-). We included 2039 participants from the observational Translational Biomarkers in Aging and Dementia (TRIAD) and Alzheimer's Disease Neuroimaging Initiative cohorts, categorized into 840 A-E-, 251 A-E+, 386 A+E4-, and 616 A+E4+. Longitudinal data were available for 1045 participants. RESULTS: In TRIAD, ALZpath p-tau217 (β = 0.45, p = 0.02) and p-tau217+^Janssen (β = 0.67, p = 0.002), and in ADNI p-tau217 (β = 0.90, p = 0.002) increased faster in A+E4+. This was not the case in E- or A- individuals or for p-tau181 and p-tau231. DISCUSSION: These findings suggest p-tau217 as a marker of faster progression in APOE ɛ4 carriers, highlighting its potential in disease stratification. HIGHLIGHTS: Blood phosphorylated tau (p-tau)217 increases faster in apolipoprotein E (APOE) ɛ4 carriers with amyloid pathology. p-tau181 and p-tau231 do not increase faster in APOE ɛ4 carriers. APOE ɛ4 carriership does not change p-tau in individuals without amyloid pathology.