PRF1 and tuberculosis: As shown in Figure 4, in comparison to the HC group, the TB group had significantly higher percentages of CD8+ T cells secreting perforin and granzyme A (p=0.002; p=0.008), while the HIV group had significantly higher percentages of CD4+ T cells secreting perforin, CD8+ T cells secreting perforin and granzyme A (p=0.004; p=0.018; p=0.002).