To ascertain whether the abnormalities of circulating T-cell subsets in patients with hepatitis B virus (HBV)-related chronic liver diseases represent the primary immunological process or are secondary to liver disease process, peripheral T-cell subsets were analyzed by indirect immunofluorescence using monoclonal antibodies against total T cells (OKT3), T helper/inducer cells (OKT4), and T suppressor/cytotoxic cells (OKT8), in 30 asymptomatic HBV carriers without biochemical or histological evidence of liver disease, and the results were compared to 15 HBV-induced chronic active liver diseases. The results revealed that OKT4/OKT8 ratios were significantly reduced in 15 hepatitis B e antigen (HBeAg)-positive asymptomatic carriers as compared with controls, with decreased OKT4-positive cells and increased OKT8-positive cells, while T-cell subsets and ratios were normal in 15 hepatitis B e antibody (anti-HBe)-positive asymptomatic carriers. The changes of circulating T-cell subsets in 15 HBe-Ag-positive asymptomatic carriers showed no significant difference from those of 15 HBeAg-positive patients with chronic active liver diseases. These findings suggest that the deranged T-cell subsets in chronic HBV infection are not secondary to liver cell damage, but might represent the underlying immunological abnormalities which are closely related to HBeAg/anti-HBe status, and that the pathogenetic mechanism of liver cell damage in chronic HBV infection may not be simply related to circulating T-cell subsets.