[A case of autoimmune hepatitis diagnosed after acute hepatitis B]

We describe a case of autoimmune hepatitis diagnosed after acute hepatitis B. The patient was a 65-year-old man admitted because of markedly elevated transaminase level. Laboratory tests showed positive IgM-HBc antibody and a short prothorombin time. He was diagnosed as severe acute hepatitis B due to sexual transmission. He received lamivudine and steroid pulse therapy. Transaminase level increased again after steroid pulse therapy and liver atrophy progressed, so cyclosporine was induced. Liver biopsy was done because of prolonged liver function disorder. Biopsy specimens showed not only centrizonal inflammation but also interface hepatitis and bridging fibrosis, which were characteristic of autoimmune hepatitis. We diagnosed autoimmune hepatitis which became clinically evident after acute hepatitis B. Lamivudine was discontinued 7 months after diagnosis and he is now receiving 3mg prednisolone.