Hierarchy Low CD4+/CD8+ T-Cell Counts and IFN-γ Responses in HIV-1+ Individuals Correlate with Active TB and/or M.tb Co-Infection

Objective Detailed studies of correlation between HIV- M . tb co-infection and hierarchy declines of CD8+/CD4+ T-cell counts and IFN-γ responses have not been done. We conducted case-control studies to address this issue. Methods 164 HIV-1-infected individuals comprised of HIV-1 + ATB, HIV-1 + LTB and HIV-1 + TB - groups were evaluated. Immune phenotyping and complete blood count (CBC) were employed to measure CD4+ and CD8+ T-cell counts; T.SPOT.TB and intracellular cytokine staining (ICS) were utilized to detect ESAT6, CFP10 or PPD-specific IFN-γ responses. Results There were significant differences in median CD4+ T-cell counts between HIV-1 + ATB (164/μL), HIV-1 + LTB (447/μL) and HIV-1 + TB - (329/μL) groups. Hierarchy low CD4+ T-cell counts (<200/μL, 200-500/μL, >500/μL) were correlated significantly with active TB but not M . tb co-infection. Interestingly, hierarchy low CD8+ T-cell counts were not only associated significantly with active TB but also with M . tb co-infection ( P <0.001). Immunologically, HIV-1 + ATB group showed significantly lower numbers of ESAT-6-/CFP-10-specific IFN-γ+ T cells than HIV-1 + LTB group. Consistently, PPD-specific IFN-γ+CD4+/CD8+ T effector cells in HIV-1 + ATB group were significantly lower than those in HIV-1 + LTB group ( P <0.001). Conclusions Hierarchy low CD8+ T-cell counts and effector function in HIV-1-infected individuals are correlated with both M . tb co-infection and active TB. Hierarchy low CD4+ T-cell counts and Th1 effector function in HIV-1+ individuals are associated with increased frequencies of active TB, but not M . tb co-infection.