Previous studies have indicated that expression of PD-1 and CTLA-4 is upregulated on HIV-specific CD4 T cells (21), yet we did not find evidence that HIV co-infection is associated with upregulation of PD-1 and CTLA-4 expression on Mtb-specific CD4 T cells, compared with HIV-uninfected individuals. Here, CTLA4 is linked to coinfection.