CD4 and neoplasm: REP TILs were able to respond to activation in the presence of tumor cells; increases in the CD3+ (median 0.72% vs. 1.33%, P = 0.098) and CD4+ (0.46% vs. 1.08%, P = 0.012) T cell IFNγ and TNFα expressions were observed after 6 hours of co-culture (Fig. 2C).