Long-term observation of acute-onset autoimmune hepatitis presenting clinically and radiologically as acute hepatitis

Background There is yet no gold standard for the diagnosis of acute-onset autoimmune hepatitis (A-AIH), especially histologically acute AIH. As a result, long-term observation of A-AIH has been difficult and the nature is not well known. We retrospectively analyzed the clinicopathological features of A-AIH over a long prospective follow-up period. Methods Clinical, biochemical, immunological and pathological features of 30 patients (21 female, mean age 55.1 ± 13.1 years) with non-severe A-AIH “without signs of clinical and radiological chronicity” admitted to a community hospital between 2001 and 2015 who were prospectively followed for more than 2 years were analyzed retrospectively. Results Liver histology of 45% showed acute and 55% chronic hepatitis. Mean age was older, prothrombin time activity was higher, AIH scores before treatment were lower in histologically acute hepatitis than histologically chronic hepatitis significantly. Liver fibrosis was not coarse, but delicate with severe activity in most patients showing chronic hepatitis defined by our strict criteria. Median (range) follow-up period was 6.9 (2.1–16.2) years. Six (20%) patients experienced episode of relapses. All were alive at the last follow-up point. Corticosteroid was continued at 2.5–5 mg/day until the study end point without serious side effects in most patients. Serial change of alanine aminotransferase levels, immunoglobulin G levels and anti-nuclear antibody titers did not show statistical difference between histologically acute and chronic hepatitis. Conclusion Rapid progression of fibrosis could occur in A-AIH. Treatment response and long-term prognosis were good, and not different between patients with histologically acute and chronic hepatitis.