Clinical implications of antimitochondrial antibodies in type 1 autoimmune hepatitis: a longitudinal study

Autoimmune hepatitis (AIH) is a chronic liver disease characterized by the presence of antinuclear antibodies. However, antimitochondrial antibodies (AMA) and bile duct changes, which are the characteristics of primary biliary cirrhosis (PBC), can be detected in AIH patients.

Twenty patients with definite AIH were prospectively followed-up, and the serial changes in AMA profiles were determined. We also examined the correlations between these antibodies and histopathological findings in the liver.

Of the 20 patients, 7 (35%) had bile duct injury, and 2 of these 7 patients also showed chronic nonsuppurative destructive cholangitis or ductopenia of interlobular bile ducts histopathologically. Serologically, 7 patients (35%) were positive for AMA at least once by immunoblotting during the follow-up periods. There were no significant differences in biochemical hepatobiliary indices, the presence of bile duct lesions, or the changes in biochemical profiles between AMA-positive and AMA-negative AIH patients during the follow-up periods.

We confirmed that AMA and certain histopathological findings that are characteristics of PBC can be seen in some AIH patients. However, there was no significant correlation between AMA positivity and the histopathological findings in the liver, or biochemical hepatobiliary indices. Thus, the clinical implications of AMA in AIH patients remain unclear.