Characterization of Cellular Immune Responses in Thai Individuals With and Without HIV-Associated Neurocognitive Disorders.

HIV-associated neurocognitive disorder (HAND) remains a challenge despite antiretroviral therapy (ART), and has been linked to monocyte/macrophage (M/M) migration to the brain. Due to the potential impact of T cell effector mechanisms in eliminating activated/HIV-infected M/M, T cell activation may play a role in the development of HAND. We sought to investigate the relationship between cognition and both CD8+ T cell activation (HLA-DR+ /CD38+ ) and HIV-specific CD8+ T cell responses at the time of HIV diagnosis and 12 months postinitiation of ART. CD8+ T cell activation was increased in HAND compared to cognitive normal (NL) individuals and correlated directly with plasma viral load and inversely with the cognitive status. In addition, Gag-specific cytolytic activity (CD107a/b+ ) was decreased in HAND compared with NL individuals and correlated with their neurological testing, suggesting a potential role of cytotoxic CD8+ T cells in the mechanism of HAND development.