Comparison of clinical features and liver histology in acute and chronic autoimmune hepatitis

Aim: We investigated the clinical and morphological features between acute and chronic autoimmune hepatitis (AIH) with or without acute exacerbation. Methods & Results: Serum total bilirubin on average was elevated to 12 mg/dL in acute AIH, alanine aminotransferase and aspartate aminotransferase peaked to more than 1000 U/L, and serum γ‐glutamyl transpeptidase was higher in the acute type compared with the chronic type without exacerbation. Serum immunoglobulin G was lowest in all other types of AIH. A liver biopsy showed interface or lobular hepatitis with lympho‐plasmacytic infiltration, and rosette formations were frequently seen in acute AIH. There were morphological changes of central necrosis with plasmacytic infiltration and giant cell hepatitis. CK19‐positive cholangiolar cells had proliferated in the periportal area with massive necrosis, and bile duct injuries were seen in acute AIH more frequently than in the chronic type. Conclusion: Laboratory data and liver histology in acute AIH differed from those of chronic AIH and were clarified for the diagnosis of acute AIH.