Autoantibody to the liver arginase present in sera of patients with autoimmune hepatitis and chronic hepatitis

We have reported previously that immunization of rat liver arginase in rabb its induced autoantibody that is reactive with their own liver arginase and has cytotoxic activity to their hepatocytes. This promoted us to investiga te whether or not such an autoantibody is present in sera of patients with certain hepatic disorders, since the liver arginase is dominant in the live r and highly homologous in structure among ureotelic animals. By Western bl ot analysis, sera from patients with chronic hepatitis and autoimmune hepat itis were shown to have an autoantibody reacting with purified human liver arginase. Since the autoantibody was also reactive with liver arginase of r at origin to almost the same extent as that of human origin, ELISA with Tat liver arginase as a coating antigen was developed and used for the quantif ication of the autoantibody. Prominent increase of the anti-liver arginase autoantibody was found in autoimmune hepatitis, moderate increase in chroni c liver diseases, and no increase in acute hepatitis or normal controls by the ELISA, These results suggest that the increased anti-liver arginase aut oantibody might involve in some parts in the pathophysiology of the hepatit ic disorders. Assay of the autoantibody can also be utilized as a marker fo r the differentiation of certain hepatitis.