To gain insight into how the expression of tight junction proteins is altered in AD, we quantified the levels of AD-related molecules including Aβ, tau, p-tau, and apoE, and two major tight junction proteins, CLDN5 and OCLN, by ELISAs in a large sample cohort of autopsy-confirmed AD cases (N = 469; Table 1). Here, APOE is linked to Alzheimer disease.