We characterized the cytokine profile in the liver of patients with primary biliary cirrhosis (PBC). Total RNA was extracted from the biopsy specimens of 9 patients with early-stage PBC, 10 with chronic hepatitis C (CHC), and 4 normal controls. cDNA was prepared and amplified with a polymerase chain reaction using primers for interferon (IFN)-gamma and interleukin (IL)-2, -4, -5, -6, -10, -12 (p40), and -15. Cytokines such as IFN-gamma and IL-5, -6, -10, -12, and -15 were expressed in most cases of PBC. Expression rates of IL-5 and IL-6 were higher than in CHC and controls. The higher expression rate of IL-5 in PBC was associated with eosinophil infiltration. IL-2 and IL-4 were rarely detected. Semiquantitative analysis revealed that the expression of IFN-gamma and IL-10 was reversed in PBC and CHC: high IFN-gamma and low IL-10 in PBC and high IL-10 and low IFN-gamma in CHC. These results suggest that cytokine expression is skewed in PBC and both Th1 and Th2 cytokines may play a role in the pathogenesis.