The cumulative data indicate that PD-1 expression was significantly increased on M. tuberculosis-specific memory CD8 T cells in HIV/PTB compared to PTB (P < 0.05) (Fig. 6D), indicating that HIV infection strongly influenced PD-1 expression on M. tuberculosis-specific CD8 T cells and was associated with reduced IL-2 production capacity. Here, CD8A is linked to HIV infectious disease.