Clinical features and outcomes of patients with drug-induced autoimmune hepatitis: a retrospective cohort study.

BACKGROUND Drugs and herbal products can induce autoimmune hepatitis. We assessed frequency and clinical outcomes of patients suffering from drug-induced autoimmune hepatitis. METHODS All patients with drug-induced liver injury admitted between 2000 and 2011 were retrospectively studied. Diagnoses of drug-induced autoimmune hepatitis and idiopathic autoimmune hepatitis were made according to simplified criteria. After discharge, all patients had regular follow-up and were contacted to update outcomes. RESULTS Among 10,270 in-hospital patients, 136 (1.3%) were diagnosed with drug-induced liver injury. Among them, 12 (8.8%) were diagnosed as drug-induced autoimmune hepatitis (41.7% males, age range 17-73); 8 (66.7%) were with jaundice at admission. Liver biopsies showed a pattern compatible with drug-induced autoimmune hepatitis, featured by severe portal inflammation and lymphoplasmacytic infiltrate. Drug-induced autoimmune hepatitis group had a shorter duration of drug intake, and higher values of transaminases and gamma globulins. All patients received immunosuppressive therapy with subsequent clinical remission, and five achieved a steroid-free long-term remission. CONCLUSIONS A diagnosis of drug-induced autoimmune hepatitis was quite rare in our cohort, and clinical pattern was similar to idiopathic autoimmune hepatitis. Severe portal inflammation, prominent portal-plasma cells, rosette formation and severe focal necrosis were significantly more frequent in drug-induced autoimmune hepatitis as compared to drug-induced liver injury.