ALL-TRANS-RETINOIC ACID INHIBITION OF ANTI-CD3-INDUCED T-CELL APOPTOSIS IN HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION MOSTLY CONCERNS CD4 T-LYMPHOCYTES AND IS MEDIATED VIA REGULATION OF CD95 LIGAND EXPRESSION

This study analyzes the influence of all-trans retinoid acid (tRA) on apoptosis of peripheral lymphocytes from human immunodeficiency virus (HIV)-positive patients. tRA inhibits the ex vivo apoptosis in T cells ; a more potent effect was observed on activation-induced apoptosis, P henotypic characterization of T cell subsets prevented from anti-CD3-i nduced apoptosis by tRA revealed a more potent effect on CD4 T cells, A central regulatory system for apoptosis is the CD95 system, and inap propriate induction of this pathway is thought to contribute to AIDS p athogenesis, In investigation of CD95-based apoptosis, tRA had no effe ct on activation-dependent induction of CD95 on T lymphocytes, but it: inhibited the induction of CD95 ligand expression on anti-CD3-activat ed T cells. The previously reported in vivo effect of tRA inhibiting H IV-associated apoptosis and the present observations suggest that tRA could be considered to down-regulate apoptosis associated with AIDS pa thogenesis.