['The significance of bile duct injury and ductular reaction in biopsies from autoimmune hepatitis patients is not clear. We aim to establish the prevalence and clinical relevance of both phenomena in autoimmune hepatitis.', 'Cases of newly diagnosed, untreated autoimmune hepatitis without overlap syndrome were selected. Pretreatment and follow up biopsies were scored for inflammation, fibrosis, bile ductal injury and ductular reaction.', 'Thirty-five cases were studied of whom 14 cases had follow up biopsies. Bile duct injury was present in 29 cases (83%), mostly in a PBC-like pattern and was not correlated with demographical or laboratory findings. Ductular reaction, observed in 25 of 35 cases (71%) using conventional histology and in 30 of 32 cases (94%) using immunohistochemistry, was correlated with portal and lobular inflammation, interface hepatitis and centrilobular necrosis as well as bile duct injury and fibrosis. In 11 of 14 cases (79%) ductular reaction remained present on post-treatment biopsy whereas bile duct injury persisted in six of 14 (43%) of cases.'] Are bile ductal injury and ductular reaction frequent phenomena with different significance in autoimmune hepatitis?