Dynamics of cytomegalovirus (CMV)-specific T cells in HIV-1-infected individuals progressing to AIDS with CMV end-organ disease

Background. Since cytomegalovirus (CMV) infection can cause serious clinical complications in immunocompromised individuals, we assessed cellular immune requirements for protection against CMV end-organ disease (CMV-EOD) in human immunodeficiency virus type 1 (HIV-1) infection. Methods. Longitudinal samples from HIV-1-infected patients in the Amsterdam cohort were analyzed. Dynamics of CMV-specific CD8(+) and CD4(+) T cell responses were analyzed by 4-color fluorescence analysis using major histocompatibility class I CMV peptide-tetramers and by intracellular staining for perforin, granzyme B, and interferon (IFN)-gamma after stimulation with CMV-specific stimuli. CMV load was measured in parallel. Results. In individuals progressing to acquired immunodeficiency syndrome with CMV-EOD, CMV-specific IFN-gamma-producing CD4(+) T cells disappeared during the year before onset of CMV-EOD. This disappearance was accompanied by a sharp increase in CMV load before onset of disease. Despite increasing CMV-specific CD8(+) T cell counts, decreasing CMV-specific IFN-gamma-producing CD8(+) T cell counts were found over time. In contrast, the percentage of CMV-specific perforin- and granzyme B - expressing CD8(+) T cells increased. Conclusions. Our data indicate that insufficient help of CD4(+) T cells may cause loss of IFN-gamma-producing CD8(+) T cells and loss of control of CMV dissemination. Increasing CMV-infected cell counts in the face of high CMV-specific perforin- and granzyme B - expressing CD8(+) T cell counts may explain the immune pathological characteristics of CMV disease