Depletion of natural killer cells in the colonic lamina propria of viraemic HIV-1-infected individuals.
HIV-1 infection is known to have a detrimental impact on peripheral blood natural killer cell phenotype and function. Chronic HIV-1 also causes a substantial depletion of CD4+ T cells in the gastrointestinal tract and the blood. To investigate the impact of chronic HIV-1 infection with on natural killer cell populations in the gastrointestinal tract and the effect of suppression of plasma viraemia with antiretroviral therapy. Lymphocyte populations were extracted from the lamina propria of biopsies taken from the sigmoid colon of HIV-1-infected and uninfected individuals. The proportions of natural killer cell subsets were compared in viraemic (n = 15) and aviraemic HIV-1-positive, HAART-treated individuals (n = 27) and HIV-1 negative control individuals (n = 26) using flow cytometry on gated subsets. Natural killer cells are depleted in colonic biopsies from HIV-1-infected individuals with detectable plasma virus in comparison with HIV-1-negative individuals. A significant increase in the proportion of both natural killer and CD4+ T cells in the colonic lamina propria is observed in aviraemic individuals compared to viraemic individuals. Chronic HIV-1 infection results in depletion of both natural killer cells and CD4+ T cells in colonic tissue and antiretroviral therapy results in a recovery of these subsets in individuals with undetectable plasma viral load.