Human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy maintain activated CD8(+) T cell subsets as a strong adaptive immune response to cytomegalovirus

CD8(+) T lymphocyte function specific for human cytomegalovirus (CMV) was e valuated in 14 patients infected with human immunodeficiency virus (HIV) re ceiving highly active anti-retroviral therapy (HAART) and 26 CMV-seropositi ve donors without HIV infection. Fifty-seven percent of the HIV-infected gr oup had CMV-specific cytolytic activity in freshly isolated peripheral bloo d mononuclear cells (PBMC) against targets expressing CMV pp65. Both interf eron (IFN)-gamma secretion by CD8(+) T cells and the frequency of human leu kocyte antigen (HLA)-tetramer-positive T cells in HLA-A*0201-positive HIV-i nfected subjects correlated with CMV-specific cytolysis. In contrast, PBMC from healthy CMV-seropositive donors did not have either measurable CMV-spe cific cytolysis or secretion of IFN-gamma without in vitro stimulation. The T helper response to CMV antigens was vigorous in healthy CMV-seropositive donors but low in the cohort of HIV-infected patients. Potent CD8(+) cytot oxic T lymphocyte responses to CMV in HIV-infected patients receiving HAART is the converse of what is found in healthy CMV-seropositive subjects and may be the predominant adaptive immune response against CMV in HIV-infected patients.