PRF1 and tuberculosis: Moreover, the release of perforin, granzyme B, granulysin and IFN-γ from effector cells may play a major role in host immune mechanisms efficient in restricting the growth of Mtb. In this study, the coordinated release of these effector molecules by PBMCs from active TB or HIV/TB coinfected patients after in vitro stimulation with PPD or avirulent Mtb, H37Ra was investigated in association with clinical outcomes before and after anti-TB treatment.