Normalization of natural killer cell activity with effective antiretroviral therapy coincides with restoration of natural killer cell receptor expression.

Natural Killer (NK) cell function is likely important in the control of HIV infection. We evaluated the impact of potent antiretroviral therapy (ART) on NK cell number and activity in ART naive patients over a period of 48 weeks. To address potential mechanisms of restored NK activity with ART a cross-sectional study was undertaken to evaluate surface expression of CD94, CD158a, CD158b, p70 and CD161, receptors known to regulate NK cell cytolytic activity. Median baseline NK activity was 56.09 lytic units for 10% lysis (LU10) and decreased to 28.18 LU10 and 18.42 LU10 at 8 and 24 weeks respectively, levels similar to HIV seronegative individuals. Expression of CD158a, and CD161 was greater in individuals not receiving ART as compared individuals receiving ART or HIV seronegative individuals. Normalization of NK cytolysis due to ART coincides with restoration of NK receptor expression, indicating a role for NK activity in HIV immunopathogenesis