In this study, we aimed to add to and put our previous findings on P-tau into context, by evaluating the association of the plasma biomarkers, Aβ42/40 ratio, NfL, and GFAP, all reflecting different disease processes, with AD copathology, clinical features, and progression of cognition in DLB, leveraging a large multicenter cohort from the European-Dementia With Lewy Bodies (E-DLB) consortium. This evidence concerns the gene GFAP and Alzheimer disease.