Elevated humoral response to cytomegalovirus in HIV-infected individuals with poor CD4 ⁺ T-cell immune recovery

Abstract

Some HIV-infected c-ART-suppressed individuals show incomplete CD4 ⁺ T-cell recovery, abnormal T-cell activation and higher mortality. One potential source of immune activation could be coinfection with cytomegalovirus (CMV). IgG and IgM levels, immune activation, inflammation and T-cell death in c-ART-suppressed individuals with CD4 ⁺ T-cell counts >350 cells/μL (immunoconcordant, n = 133) or <350 cells/μL (immunodiscordant, n = 95) were analyzed to evaluate the effect of CMV humoral response on immune recovery. In total, 27 HIV-uninfected individuals were included as controls. In addition, the presence of CMV IgM antibodies was retrospectively analyzed in 58 immunoconcordant individuals and 66 immunodiscordant individuals. Increased CMV IgG levels were observed in individuals with poor immune reconstitution (p = 0.0002). Increased CMV IgG responses were significantly correlated with lower nadir and absolute CD4 ⁺ T-cell counts. In contrast, CMV IgG responses were positively correlated with activation (HLA-DR ⁺) and death markers in CD4 ⁺ T-cells and activated memory CD8 ⁺ T-cells (CD45RA ^-CD38 ⁺). Longitudinal subanalysis revealed an increased frequency of IgM ⁺ samples in individuals with poor CD4 ⁺ T-cell recovery, and an association was observed between retrospective IgM positivity and the current level of IgG. The magnitude of the humoral immune response to CMV is associated with nadir CD4 ⁺ T-cell counts, inflammation, immune activation and CD4 ⁺ T-cell death, thus suggesting that CMV infection may be a relevant driving force in the increased morbidity/mortality observed in HIV ⁺ individuals with poor CD4 ⁺ T-cell recovery.