Assessment of the histopathological key features in autoimmune hepatitis

Aims: In this study, we aimed to evaluate the use of typical histological features of both the revised original (1999) and simplified (2008) criteria in the diagnosis of autoimmune hepatitis (AIH) in clinical practice. Methods and results: We performed a detailed histopathological evaluation of the pretreatment biopsies of 63 AIH patients, and used biopsies of 62 untreated chronic viral hepatitis patients [hepatitis B (n = 21) or hepatitis C (n = 41)] as a reference cohort. Biopsies were systematically reviewed for inflammation, fibrosis and the presence of interface hepatitis, plasma cells, rosettes and emperipolesis with a well-defined assessment method. AIH biopsies showed more interface hepatitis (87% versus 63%, P = 0.002), more plasma cell-rich infiltrates (48% versus 27%, P = 0.02), more rosettes (49% versus 23%, P = 0.004) and more emperipolesis (78% versus 50%, P = 0.001) than chronic viral hepatitis biopsies. Emperipolesis (P = 0.01) and rosettes (P < 0.01) were superior to plasma cells and interface hepatitis as independent predictors for AIH. Moderate to severe lymphocytic cholangitis was found in 28% of AIH patients. Conclusions: Emperipolesis and rosette formation are superior histological predictors of AIH than the classic hallmark features of interface hepatitis and plasma cells. In addition, moderate to severe lymphocytic cholangitis does not preclude the diagnosis of AIH.