PRF1 and tuberculosis: Subgroup analysis stratified by age revealed that although there were no significant differences in LAG-3 gene expression among TB patients in different age groups, younger patients (under 60 years old), tended to have higher levels of GZMB and PRF1 mRNA, while older patients (over 60 years old) had relatively higher IL-2 levels (Supplementary Figures 2E-I).