Short-term antiretroviral therapy fails to reduce the expanded activated CCR5-expressing CD4+ T lymphocyte population or to restore the depleted naive population in chronically HIV-infected individuals with active pulmonary tuberculosis.

The effective role of antiretroviral (ARV) therapy in the regulation of CD4 T cell subset distribution, coreceptor expression, and activation status in individuals with chronic HIV also presenting with active pulmonary TB is not clearly understood. A cross-sectional analysis was performed on a total of 137 South African individuals. CCR5, CXCR4, and CD38 expression of CD4 T cell subsets in HIV-infected individuals with and without active pulmonary tuberculosis (TB) disease, pre- and post-ARV therapy, were determined by flow cytometry. In treatment-naive patients, CD4 T cells showed elevated surface expression of CCR5 and CD38 in TB/HIV coinfection as compared to HIV infection alone despite the overall percentage of CD4 T cells expressing CCR5 being reduced. Total CD38+ CD4 T cells were not significantly increased in either group; however, mean CD38 fluorescence was significantly higher in the context of TB infection. HIV/TB-coinfected individuals also displayed an increased percentage of activated (CD38+) CCR5+ CD4 T cells as compared to HIV patients alone. The naive CD4 T cell subset was depleted similarly in both HIV and HIV/TB groups. Only the HIV treatment group and not the TB-coinfected treatment group showed significantly decreased activated CCR5+ CD4 T cells, an increased percentage of naive T cells, and a decreased percentage of antigen-experienced T cells. This study highlighted an association of TB disease with immune activation, particularly of the CCR5+ CD4 T cell subset in HIV infection and the differential impact of ARV treatment. Further studies are needed to understand how TB coinfection confounds normal responses to ARV.