Inverse correlation between CD8+ lymphocyte apoptosis and CD4+ cell counts during potent antiretroviral therapy in HIV patients

Abstract

We have addressed the relationships between inhibition of CD4+ and CD8+ cell apoptosis and CD4+ cell recovery in HIV patients undergoing potent antiretroviral therapy (PART) by correlating apoptosis levels with virological and immunological parameters detected over a long-term period in HIV patients undergoing therapy. Twenty-two HIV-1-infected patients undergoing PART were enrolled in a long-term, open longitudinal study. Data derived from 17 patients with successful response to therapy (TS; median time of follow-up 36 months, range 24-36 months) were used for correlation studies. Apoptosis was evaluated after short-term culture of peripheral blood lymphocytes by flow cytometry analysis of isolated nuclei or of annexin V/CD4, annexin V/CD8 double-stained cells. Sustained, noticeable levels of apoptosis inhibition in peripheral blood mononuclear cells were measured, in the long-term, in 16 of the 17 TS patients. Levels of total cell apoptosis correlated with levels of CD8+ apoptotic cells more significantly than with levels of CD4+ apoptotic cells. In addition, CD4+ cell counts were correlated inversely with levels of CD8+ apoptotic cells in a highly significant fashion, but not with levels of CD4+ apoptotic cells. Our data indicate that the increase of CD4+ lymphocytes in HIV patients, as a consequence of successful response to PART, may be related to changes in apoptosis level occurring in the CD8+, and not in the CD4+, cell compartment.