Abstract: Objective To evaluate the changes of CD4+ CD25+ regulatory cells (Treg) in peripheral blood and the serum levels of transforming growth factor beta-1 (TGF-β1 ) in patients with hepatocellular carcinoma. Methods The ratios of Treg in peripheral blood of 32 patients with hepatocellular carcinoma, 25 cases with
metastatic liver cancer and 30 healthy controls, were determined by flow cytometry. Meanwhile, the serum levels of TGF-β1  were detected by ELISA. Results The ratio of Treg in total CD4+ T cells in peripheral blood [(9.61 ± 3.32)% vs (5.88 ± 1.16)%, P ＜ 0.01] and the serum levels of TGF-β1  [(98.10 ± 20.41) ng/L vs (9.78
± 2.54) ng/L, P ＜ 0.01] of patients with hepatocellular carcinoma were significantly higher than those in healthy controls. Meanwhile, the ratio of Treg in total CD4+  T cells in peripheral blood [(9.61 ± 3.32)% vs (7.56 ± 2.17)%, P ＜ 0.05] and the serum levels of TGF-β1  [(98.10 ± 20.41) ng/L vs (29.33 ± 6.90) ng/L, P ＜ 0.01] of patients with hepatocellular carcinoma was higher compared with those in metastatic liver cancer (P ＜ 0.05 or P ＜ 0.01). The correlation indicated that the ratio of Treg in total CD4+ T cells in peripheral blood were positively related with TGF-β1  levels and tumor clinical stages (r = 0.698 and 0.762, P ＜ 0.01), but negatively correlated with Karnofsky performance status score (KPS) (r =  －0.642, P ＜ 0.01). Conclusions The ratio of Treg in total CD4+ T cells in peripheral blood from hepatocellular carcinoma is higher and correlated with TGF-β1  level, tumor clinical stages and KPS. It might be helpful to determine the prognosis of hepatocellular carcinoma by detecting the ratio of Treg in total CD4+ T cells in peripheral blood.