[A case of probable autoimmune hepatitis from which the persistence of hepatitis A IgM antibody, and the improvement was pathologically obtained by ursodeoxycholic acid medication].

We present a 68 years old woman who was referred to our department due to impaired liver function. Hepatitis A IgM antibody and anti-nuclear antibody were positive, IgG, and gamma-globulin were elevated. Percutaneous liver biopsy was performed and autoimmune hepatitis was suspected pathologically. Oral administration of ursodeoxycholic acid was started and liver function was normalized three months later. The improvement of a hepatitis image was examined by percutaneous liver biopsy one year later. Although hepatitis A IgM antibody was positive throughout the course, hepatitis A virusemia was not considered the cause of persistent positive hepatitis A. IgM antibody could not be clarified. There was a possibility of a non-specific reaction and abnormalities in antibody production control were considered possible. We present this case and discuss the previous literature.