Tissue localization of Australia antigen immune complexes in acute and chronic hepatitis and liver cirrhosis.

In a significant percentage of examined cases of fulminant hepatitis, subacute hepatitis, chronic aggressive hepatitis, liver cirrhosis and chronic persistent hepatitis, Australia (hepatitis-associated) antigen (Au HAA) was identified in the liver and in extrahepatic locations. The several immunofluorescent patterns of Au HAA localization in hepatocytes strongly suggested various stages of Au HAA accumulation and release. Deposits of a mixture of immunoglobulins G and M and occasionally beta1C-globulin were found in the cytoplasm of Au HAA containing hepatocytes, on their plasma membranes, on or in the nuclei, in the cytoplasm of Kupffer cells and, rarely, in the sinusoids. The accompanying tissue changes were hepatocellular degeneration and necrosis. These intra- and extracellular complexes of Au HAA and immunoglobulins displayed strong affinity for guinea pig complement in the immunohistochemical complement fixation reaction. When tested by immunodiffusion in agar, IgG dissociated from these complexes by potassium thiocyanate (KSCN) treatment showed anti-Au HAA specificity. In fulminant hepatitis neither Au HAA nor immunoglobulins and complement were found in the liver. In chronic aggressive hepatitis and subacute hepatitis the amount of the Au HAA immune complexes identified in the liver was approximately inversely proportional to the extent and severity of the parenchymal lesions. In liver cirrhosis and chronic persistent hepatitis there was a positive correlation between the amount of the Au HAA immune complexes found in the liver and the degree of hepatocellular damage. The deposits of Au HAA, identified in extrahepatic locations including germinal centers of lymph nodes and spleen, kidney glomeruli and blood vessel walls, were as a rule accompanied by deposits of IgG, IgM, beta1C-globulin and fibrin. All these deposits showed strong affinity for guinea pig complement in the immunohistochemical reaction of complement fixation. Germinal center activation, chronic membraneous glomerulonephritis, panarteritis and simple arteriolar hyalinosis were found at sites of localization of these deposits.