Apoptosis in HIV-infected individuals is an early marker occurring independently of high viremia

We have analyzed the immunoreactivity of peripheral blood mononuclear cells by determining the proliferative response to four mitogens, one superantigen, and one recall antigen together with the occurrence of activation-induced apoptosis from 213 HIV-1-seropositive individuals from all stages of infection. The expected decline of immunoreactivity observed with time after infection correlated with disease progression and the loss of CD4 cells. Apoptosis was already detectable at the early stages of infection and increased only slightly with disease progression. In analyzing 13 patients with high and low apoptosis rates we observed no correlation to HIV-1 viremia. Our results argue that mitogen-induced apoptosis occurs in both infected and noninfected T cells and can be detected before mitogenic responsiveness is reduced.