By contrast, Mtb-specific CD4 T cells from the same individuals consistently exhibited markedly lower proportions of CTLA-4+PD-1+ cells and PD-1 single-positive cells, compared with virus-specific CD4 T cells in both HIV-infected and HIV-uninfected individuals with LTBI and active TB (Figures 5B,D). Here, CTLA4 is linked to tuberculosis.