Study of the Clinical Features of Autoimmune Hepatitis

The purpose of this study is to explore the pathogenes, clinical characteristics, laboratory and histological examination results, treatment and prognosis of autoimmune hepatitis(AIH). At phase 1, the investigators focus on studying of the clinical characteristics of acute autoimmune hepatitis, and then will study the difference about treatment effects between acute autoimmune hepatitis and chronic AIH. Morever, the investigators have noticed that drug induced AIH have some special characteristics that may be beneficial to distinguish it with durg induced liver disease. Therefore the investigators will do some studies about drug induced AIH or other disease which maybe related to the onset of AIH.