Innate natural killer cell phenotype and function during HIV-1 infection: potential avenues for modulation

Recent developments in the field of innate immunity and the discovery of novel functions of natural killer (NK) cells have opened up potential new avenues for therapeutic intervention in HIV-1 infection. NK cells inhibit virus entry into CD4+ T cells, kill infected CD4+ T cells, help the maturation of antigen-specific T-cell responses and promote physiological repair processes throughout the body. NK cells are numerically and functionally compromised during chronic HIV-1 infection, with reduced ability to kill infected cells and to produce regulatory cytokines. HAART induces a recovery in cell number and in some functions of blood NK cells, whilst others remain suppressed. This article reviews the potential of supplementary cytokines, hormones and therapeutic vaccines to reconstitute NK cell functions in people with HIV-1 infection receiving HAART.