Autoantibodies against liver-specific membrane lipoprotein in acute and chronic liver diseases: studies on organ-, species-, and disease-specificity.

A double antibody radioimmunoprecipitation test was used to detect anti-human LSP, anti-rabbit LSP, and autoantibodies against the human kidney equivalent of LSP (anti-HKP) in patients' serum. Anti-human LSP was found in 27/62 cases with chronic active liver disease (CALD), 9/16 cases with chronic persistent hepatitis (CPH), and 14/33 patients with acute viral hepatitis (AVH), 2/10 patients with ;inactive' cirrhosis of the liver (Ci), 4/14 patients with alcohol induced liver disease (ALD), 1/7 patients with miscellaneous liver diseases (MLD), and in 6/58 patients with primary non-hepatic autoimmune disease (PNHA). Frequencies of anti-LSP did not depend on HBsAg status. Anti-rabbit LSP was detected in only 9% of patients with AVH as compared with 42% for anti-human LSP. No such difference was observed in the other groups of patients. Anti-HKP was found in 6/62 patients with CALD, 1/7 patients with MLD, and 2/58 patients with PNHA; no anti-HKP occurred in patients with CPH, AVH, ALD, and Ci. The frequency of anti-LSP was not correlated with the presence of non-organ-specific autoantibodies in patients with CALD; furthermore, no correlation with sex-distribution, age, gammaglobulin levels, and SGOT occurred in this group of patients. No correlation existed between anti-LSP and liver membrane autoantibodies detected by indirect immunofluorescence on isolated rabbit hepatocytes (LMA). The reported data show that naturally occurring anti-LSP, characteristic for acute and chronic inflammatory liver diseases, are mostly directed against organ-specific determinants of the LSP complex. It is suggested that the occurrence of antibodies to species-specific determinants of LSP reflects a transient state of autoimmunity. The LMA immunofluorescence test seems to detect antibodies against other liver membrane antigens as well as LSP.