Abstract: Objective The aim of this study was to investigate clinical features of patients with drug-induced autoimmune hepatitis (DILI-AIH), autoimmune hepatitis (AIH) and drug-induced liver injury (DILI). Methods Clinical data from 18 patients with DILI-AIH, 25 patients with AIH and 32 patients with DILI were retrospectively collected between June 2023 and June 2025, and clinical materials, immunological manifestations, histopathological study and response to treatment were reviewed. Results Percentages of female and concomitant autoimmune diseases in patients with DILI-AIH and with AIH were much higher than in those with DILI(P<0.05);serum ALP total bilirubin levels in patients with DILI were 242.1(164.5,333.2)U/L and 86.3(45.7,140.2)μmol/L,both much higher than [165.3(120.4,230.6)U/L and 56.3(32.3,98.4)μmol/L,respectively, P<0.05] in those with DILI-AIH or [130.3(105.4,193.4)U/L and 48.2(25.2,80.4)μmol/L,respectively, P<0.05] in those AIH,while serum IgG level as well as serum ANA and SMA positive rates were much lower than in those with DILI-AIH or with AIH(P<0.05);incidences of liver tissue interface hepatitis and plasma cell infiltration in patients with DILI-AIH or with AIH were significantly higher than in those with DILI(P<0.05); all patients with DILI-AIH and with AHI received steroid therapy, but only a few with DILI did(P<0.05),and serum ALT level returning to normal took longer times than in those with DILI(P<0.05), with more steroid dependence or resistant to steroid in those DILI-AIH or with AIH (P<0.05). Conclusion DILI-AIH shares clinical, immunological, and histopathological features of both DILI and AIH, much similar to clinical manifestations and prognosis in patients with AIH. These findings suggest that DILI-AIH might represent an immune-mediated liver injury triggered by medicines. In individuals with a history of drug exposure accompanied with elevated serum IgG levels and positive autoantibodies, DILI-AIH should be considered. Early recognition and appropriate immunosuppressive therapy might improve long-term outcomes.

Key words: Drug-induced autoimmune hepatitis, Autoimmune hepatitis, Drug-induced liver injury, Clinical features