ObjectiveTo investigate the condition of autoimmunity in patients infected with the hepatitis B virus (HBV). MethodsSerum samples were collected from 120 HBV-infected patients and 50 healthy controls. Antinuclear antibodies (ANA) and smooth muscle antibodies (SMA) were detected by indirect immunofluorescence. Antimitochondrial antibody-M2 antigen (AMA-M2) was detected by enzyme-linked immunosorbent assay. Rheumatoid factor (RF) was detected by a scatter turbidity method. Antibodies against soluble liver antigen (SLA/LP), liver kidney microsomal (LKM-1), and liver cystosol antigen type 1 (LC-1) were detected by immunoblotting. ResultsThe positive rate autoantibodies was significantly higher in the HBV-infected patients (48.3% vs. controls: 4.0%, χ2=30.375, P＜0.05. However, among the HBV-infected patients, there were no significant differences in the positive rates of autoantibodies between the sub-groups of HBV carriers (40.0%), hepatitis (40.0%), hepatic sclerosis (56.7%), and hepatic cancer (56.7%) (χ2=3.337, P=0.343). ANA and RF were the most frequently detected autoantibodies. The ANA titer was mostly 1∶100, and the ANA pattern was mostly of the “homogeneous type” or “granular type”. The liver profile (IgG) was taken for patients with ANA titer ≥1∶320 and as a result there were only two positive samples of AMA-M2 in the hepatic sclerosis group, indicating that HBV infection can induce autoimmune liver disease. The levels of aspartate aminotransferase were significantly different between the HBV-infected patients who were negative for autoantibodies and those who were positive for autoantibodies (P=0.007), indicating that the autoantibodies contributed to liver function damage. ConclusionHBV-infected individuals express many kinds of autoantibodies, which may promote damage to liver function and should be paid attention to by treating physicians.