CD4 and hepatocellular carcinoma: As expected, the frequency of CD4+CD25+ T cells in tumor-infiltrating lymphocyte (TIL), representing 34.9±2.7% of CD4+ T cells, was significantly higher than those in non-tumor-infiltrating lymphocyte (NIL; 7.8±0.6%), and peripheral blood mononuclear cells from HCC patients (cPBMC; 16.7±1.2%), HBV patients (vPBMC; 11.7±1.3%) and healthy donors (nPBMC; 6.7±0.7%) (P<0.001, Figure 1a, b).