Acute exacerbation of autoimmune liver disease associated with hantaviral infection

Detection of hantaviral antibodies among patients with hepatitis of unknown etiology in Japan

Hantaviral antibodies were detected in the sera from patients with hepatic disease of unknown etiology in Japan by several different serological diagnostic methods. A total of 105 sera from diseased patients which were negative to A-G hepatitis virus infections in the Tokyo area were tested. Among them, 3 out of 73 sera from patients with chronic hepatic disease were positive to hantaviral antibody by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescent antibody assay (IFA) and Western blot analysis (WB). Neutralizing antibody titers of the 3 sera to Seoul virus (SEO) were 4 to 8 times higher than those to Hantaan virus (HTN). However, all of the 32 sera from patients with acute hepatitis were negative for hantaviral antibody. Among the 60 patients with chronic hepatitis in Hokkaido which were serologically negative to B and C hepatitis virus infection, one was positive for hantaviral antibody by ELISA and WB. In contrast, the sera from healthy adults in Japan, 550 from the Honshu and Kyushu regions, and 1,000 from the Hokkaido region, were negative for hantavirus antibody. These results show that hantaviral antibodies are more frequently detected in patients with hepatic disease than in healthy adults. However, the observation that no positive sera were detected from patients with acute hepatitis implies that hantavirus might not be directly related to hepatitis.

Autoimmune liver disease

The incidence and prevalence of autoimmune hepatitis are greater than expected among white northern Europeans. Patients with type 2 autoimmune hepatitis have different HLA frequencies than patients with type 1 disease and HLA-DRB1*07 may be an important risk factor. Hepatitis C virus can trigger autoimmune hepatitis after needlestick inoculation. Elderly patients have milder disease than young patients and they are frequently untreated. Cryptogenic chronic hepatitis is indistinguishable from autoimmune hepatitis and it responds as well to corticosteroids. Variant syndromes are common and the degree of cholestasis influences the treatment response. Endomysial antibodies indicate celiac sprue in asymptomatic patients, and multiple endocrinopathies in individuals with type 2 disease may reflect molecular mimicries and cross-reacting autoantibodies. Phase I (cytochromes P-450) and phase II (uridine diphosphate glucuronosyltransferases) drug-metabolizing enzymes are the autoantigens of syndromes characterized by liver/kidney microsomal autoantibodies. T-cell vaccination prevents the occurrence of experimental hepatitis in mice and it can also treat the disease. Liver transplantation can be complicated by recurrent disease, frequent allograft rejection, and de novo autoimmune hepatitis.