Natural Killer cells from long-term non-progressor HIV patients are characterized by altered phenotype and function.

Natural killer (NK) cells are part of the innate immune system important in the control of viral infections and recent evidence suggests that they may play a role in the pathogenesis of HIV. Long-term non-progressor (LTNP) HIV patients who control replication of the virus and show a delayed disease progression have naturally occurring successful immune responses to HIV. We investigated a role for NK cells in these patients. In agreement with previous reports, NK cell cytotoxic activity was decreased in viremic HIV patients relative to healthy individuals (p < 0.05). Viremic HIV patients showed an altered cell surface phenotype, including a reduction in natural cytotoxicity receptor expression and an increase in leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) expression. These phenotypic changes were also present in LTNP patients; however, these patients showed increased levels of NK cell activity relative to viremic HIV patient group.