HIV patients stable on ART retain evidence of a high CMV load but changes to Natural Killer cell phenotypes reflect both HIV and CMV

Abstract

Background: Whilst ART corrects many effects of HIV disease, T cell populations retain features of accelerated immunological aging. Methods: Here we analyse phenotypic changes to natural killer (NK) cells in HIV patients who began ART with <200 CD4 T-cells/µl and maintained virological control for 12-17 years, compared with CMV seropositive and seronegative healthy control donors. Results: Humoral responses to CMV antigens (lysate, gB, IE-1) remain elevated in the patients (P <0.0001) despite the long duration of ART. Patient's NK cells responded poorly to K562 cells when assessed by CD107a and IFNγ, but this could not be attributed to CMV as responses were low in CMV-seronegative controls. Moreover HIV (and not CMV) increased expression of CD57 on CD56lo cells. Conclusions: Comparisons with published studies suggest that CMV accelerates age-related increases in CD57 expression but levels plateau by 60-70 years of age, so the effect of CMV disappears. In HIV patients the plateau is higher and perhaps reached sooner.