Analysis of apoptosis and DR5 in HIV-1–infected patients and uninfected controls. (A) Flow cytometric analysis of annexin V⁺ and DR5⁺ CD4⁺ T cells from 16 uninfected control donors (HIV^-) and 22 HIV-1–infected patients (HIV⁺). P values were calculated using 2-tailed Student t test. (B) Linear regression analysis of DR5-mediated CD4⁺ T-cell apoptosis (DR5⁺annexin V⁺) compared with all apoptotic CD4⁺ T cells (annexin V⁺) performed in the same cohort. (C) PBMCs from 5 HIV-1–infected patients were cultured for 48 hours with (+) or without (-) anti-DR5 blocking antibody. CD3⁺ CD4⁺ T cells were analyzed for annexin V by FACS.