Definition and classification of autoimmune hepatitis 1999 (on behalf of the International Autoimmune Hepatitis Group)

Abstract

At the beginning of the 1990s there was considerable uncertainty about the diagnostic criteria for the condition which was then known as ‘lupoid’ or “autoimmune chronic active” hepatitis (AICAH). It was recognized that the disease, which had been increasingly diagnosed during the 1970s and 1980s, was markedly heterogeneous with respect to its clinical and laboratory manifestations and possibly also its pathogenesis1. The hepatitis C virus (HCV) had been very recently identified23 and early reports suggested that a high proportion of patients with presumed AICAH had HCV infections and, conversely, that many patients with chronic hepatitis C had features (notably mild to moderate hypergammaglobulinemia and circulating autoantibodies) associated with AICAH4-6. Additionally, it was recognized that these features, as well as the histological changes of chronic active hepatitis, can often be seen at various stages in other liver disorders including primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), Wilson’s disease and some forms of drug- and alcohol-induced liver disease. The advent of interferon (IFN) therapy for chronic viral hepatitis was also presenting a problem for clinical management because it was becoming apparent that IFN can provoke (or unmask pre-existing) autoimmune conditions and that accuracy of diagnosis was crucial7.