NK cells of HIV-1-infected patients with poor CD4+ T-cell reconstitution despite suppressive HAART show reduced IFN-γ production and high frequency of autoreactive CD56bright cells

HIV-1-infected patients failing to recover CD4(+) T-cell count despite HAART (immunological non-responders, NRs), are at increased risk of disease progression and death. To better understand the NR status, we performed a comprehensive assessment of NK cells in NR patients as compared to immunologic responders. NRs exhibited an accumulation of CD56(bright) NK cells inversely correlated with CD4(+) counts. Both CD56(bright) and CD56(dim) NK cells of NRs displayed unimpaired degranulation ability, but poorly responded to cytokine stimulation in terms of NKp44 up-regulation and IFN-gamma production that may explain the susceptibility of NRs to infections and tumors. Notably, CD56(bright) NK cells from NRs showed higher cytotoxicity against autologous activated CD4(+) T cells. Moreover, NRs had reduced Treg cell counts that showed an inverse correlation with autoreactive CD56(bright) cells. These data suggest that accumulation of CD56(bright) NK cells, possibly linked to decreased homeostatic control by Tregs, contributes to poor immune reconstitution in NRs.