Is severe cryptogenic chronic hepatitis similar to autoimmune hepatitis?

Background/Aims: It has been reported that severe cryptogenic chronic hepatitis may be a subgroup of autoimmune hepatitis. The aims of this study were to investigate the clinical features, liver function tests, human leukocyte antigens and response to immunosuppressive therapy in severe cryptogenic chronic hepatitis, and to compare the findings in such patients with those in patients with autoimmune hepatitis. Methods: History of alcohol and hepatotoxic drug intake, markers of metabolic liver disease, autoantibodies (antinuclear antibody, smooth muscle antibody, antibody to liver/kidney microsome type 1), and viral markers (HBsAg, HBV DNA, anti-HCV, HCV RNA) were negative in all severe cryptogenic chronic hepatitis patients (histological activity index>9 and alanine aminotransferase level>2×normal). Fifteen cryptogenic patients (13 women; mean age, 33±16 years) and seven autoimmune patients (seven women; mean age, 28±3.9 years; five type 1; two type 2a) received prednisolone and azathioprine for at least 2 years. Results: Cryptógenic chronic hepatitis patients were similar to patients with autoimmune hepatitis with respect to age, sex, clinical presentation, liver function tests and Knodell scores at admission. HLA phenotype frequencies were comparable between cryptogenic and autoimmune groups: BW6 (77% vs. 100%), DR4 (62% vs. 57%), and HLA B8 (15% vs. 43%). The rates of complete and partial remissions achieved during therapy were 87% vs. 57% and 13% vs. 29%, respectively (p>0.05). Conclusions: The clinical, biochemical and HLA phenotypic features, and the responsiveness to immunosuppressive therapy in severe cryptogenic chronic hepatitis support the idea that it may be an autoimmune liver disease similar to autoimmune hepatitis.