A 16 year-old girl was admitted to hospital because of fatigue and somnolence,nausea,epistaxis and jaund ice.Physical examination revealed jaundice,an enlarged liver and tenderness of upper right abdom en.Laboratory tests revealed an increased level of acute liver failure,bilirubin,bile acids,GGTP and a decreased prot hrombin ratio,with elevated gamma-globulin and IgG levels,and the presence of anti-mitochondrial M2 antibodies and HBV infection markers.The patient was diagnosed with liver failure resulting from chronic hepatitis B with an autoimmune component.The treatment consisted of steroids,azathioprine,vitam in K,low-protein diet and lactulose enemas.After undergoing a molecular test(HBV DNA 3.23 × 105 IU/mL and mutations 204 and 80),the treatment was mo tient was discharged in good clinical condition,with the recommendation of continued entecavir,prednisone and azathioprine.In subsequent months,no clinical deter ioration or abnormal biochemical liver function test results were found,despite the discontinuation of immunos up pressive therapy after 10 mo.The patient cont inues entecavir therapy.