Common T cell pathways (namely cytotoxicity and apoptosis) were observed in subjects with an ‘effective’ immune response (NAE form that transitioned to the AE form at a later timepoint) in both acute and chronic HIV infection, although the genes driving these differences varied (for example, cytotoxicity was driven by GZMB, IFNG, GZMH and TNF for subject C1 and C2 tetramer comparison, but by GZMB, KLRD1 and PRF1 for subject C1 peptide comparison). This evidence concerns the gene PRF1 and HIV infectious disease.