CTLA4 and tuberculosis: Among HIV-TB co-infected individuals, we observed significantly higher frequencies of TIM-3, CTLA-4 and LAG-3 expressing CD4+ and CD8+ T cell (Figure 4A,B,E–H, respectively) and TIGIT expressing CD4+ T cell (Figure 4C) subsets as compared to HIV mono-infected individuals (p < 0.05).