High incidence of antitissue antibodies in patients experiencing chronic liver allograft rejection

Background. The precise immunologic mechanisms responsible for chronic rejection of liver allografts are unknown. We have recently shown in a rodent model that recipients of liver allografts developed non-major histocompatibility complex antitissue antibodies. The aim of the present study was to test this hypothesis in the clinical setting. Methods. Posttransplant sera of 14 patients undergoing chronic rejection and of 48 control patients (12 liver transplant patients with chronic active hepatitis or liver cirrhosis related to hepatitis C virus [HCV] infection and without chronic rejection, 10 with sclerosing cholangitis, and 26 with normal liver function tests and liver biopsy) were tested for the presence of antitissue antibodies by indirect immunofluorescence. Pretransplant sera of all these patients lacked antitissue antibodies. Results. Antitissue antibodies were detected in 71% of patients who developed chronic rejection (before or at the time of chronic rejection). This incidence was significantly greater than that observed in patients not undergoing rejection (HCV-related chronic active hepatitis, 16%; sclerosing cholangitis, 0%; normal liver biopsy, 7%). All these autoantibodies were directed against the smooth muscle and/or the nucleus. In two patients, anti-smooth muscle antibodies had an antiactin or antivimentin specificity. Conclusions. These results show a strong association between chronic allograft rejection and the development of antitissue antibodies and suggest that these antibodies could be used to identify patients at high risk of developing chronic rejection after liver transplantation.