Autoimmune hepatitis in Japan: trends in a nationwide survey

A nationwide survey of autoimmune hepatitis (AIH) patients was performed in Japan in 2015. The aims of this study were to elucidate the trends and characteristics of AIH in Japan, in addition to identifying differences in AIH between acute hepatitis and chronic hepatitis. Questionnaires about patients with AIH diagnosed from 2009 to 2013 were sent to 437 hospitals or clinics with hepatology specialists. A total of 1682 patients were enrolled. The mean age at diagnosis was 60.0 years, and 87.1 % of patients were female. Serum immunoglobulin G levels were high, peaking at 1.5-2.0 g/dL. Histological diagnoses of chronic hepatitis, acute hepatitis, and cirrhosis were seen in 79.6, 11.7, and 6.7 % of patients respectively. In addition to elevation of aminotransferase levels, the frequencies of emperipolesis and human leukocyte antigen (HLA)-DR2 positivity were higher in patients with acute hepatitis than in those with chronic hepatitis. Approximately 80 % of patients were treated with corticosteroids, and in 97.7 % of them, their condition improved. Steroid pulse therapy was more frequently given to patients with acute hepatitis than to those with chronic hepatitis. In the present nationwide survey of AIH patients in Japan, patients with acute hepatitis had clinical features different from those of patients with chronic hepatitis.