To evaluate cellular immunity, mitogen-induced lymphocyte transformation was assessed in 146 patients with chronic hepatitis B virus (HBV) infection, including 63 patients with chronic hepatitis (CH), 34 with liver cirrhosis (LC), and 49 patients combined with liver cirrhosis and hepatocellular carcinoma (HCC). The PHA-induced transformation indices (TI) were lower in patients with chronic HBV infection, especially in the LC and the HCC groups. The Con A-induced TI were also diminished in patients with chronic HBV infection. The mitogen-induced TI in patients with CH showed no significant difference in regards to different histological patterns, HBeAg/anti-HBe statuses, sex groups, age distributions, and SGPT levels. However, the mitogen-induced TI were substantially higher in CH patients with elevated serum AFP levels, especially in the group with AFP levels over 100 ng/ml. From these data, we conclude that: (1) impaired PHA-induced TI in patients with LC may partly explain the high risk factor of LC in the occurrence of HCC; (2) the reduction in TI induced by optimal concentration of Con A reflects the defective suppressor cell activity in patients with chronic HBV infection, even in patients with HCC; (3) no significant difference among the control group and patients with chronic HBV infection in PWM-induced TI implies that the response of B cells may be normal in patients with chronic HBV infection; (4) elevated mitogen-induced TI in CH patients with high AFP levels indicate that the activation of lymphocyte may contribute to the severity of inflammation and tissue damage.