Auto-immune Hepatitis

Evaluate the proportion of seronegative auto-immune hepatitis and a possible relationship with the severity of the disease. Criteria of severity will be defined by corticodependance, corticoresistance and a severe form of the disease at diagnosis (cirrhosis or fulminant hepatitis). In case of predominant seronegative forms, other auto-antibodies related to this auto-immue hepatitis will be searched.