[Histocompatibility-(HLA) antigens in patients with HBsAg positive and negative hepatitis and healthy carriers of HBsAg and anti-HBs. (author's transl)]

New own data and a survey of published data concerning the frequencies of 23 HLA antigens in patients with HBsAg positive and negative chronic active hepatitis (CAH) and healthy carriers of Hepatitis-surface antigen (HBsAg) and high titers of antibodies to HBaAg (Anti-HBs) allow to conclude as follows: 1. Patients with CAH and persistence of HBsAg show a normal frequency of HLA-B8. 2. There is no increased frequency of HLA-B8 in HBsAg negative CAH without autoimmune antibodies. 3. Only in patients with HBsAg negative CAH with autoimmune antibodies is the frequency of HLA-B8 is statistically significantly increased (p less than 0.01 after correction for the number of antigens and different groups of patients compared). These are patients with the autoimmune form of CAH. 4. There exist no significant differences in the frequencies of the HLA antigens tested in patients with HBsAg positive CAH and healthy carriers of HBsAg and Anti-HBs. Thus no indications could be found for HLA-associated factors in the different behaviour to the hepatitis-B virus.

[Humoral immune reactions on the hepatocellular plasma membrane in the experimental chronic active hepatitis in rabbits (author's transl)]

For the induction of experimental chronic active hepatitis (CAH) in rabbits long term immunization was performed with human liver-specific protein plus complete Freunds adjuvants. Serum antibodies against allogeneic hepatocellular membrane antigens could be detected after 23 weeks using isolated normal rabbit hepatocytes or by the passive hemagglutination technique with liver-specific membrane protein as antigen. Isolated hepatocytes from these rabbits showed in vivo fixed IgG on their plasma membranes in a linear and granular fluorescence pattern. Furthermore immune complexes (Raji-cell test) were detectable in the sera of these animals. After 23 weeks 3 out of 16 animals had developed a chronic active hepatitis (CAH). After 44 weeks 10 of 15 animals and after 78 weeks 6 of 7 surviving animals had a CAH. All these 7 animals had serum antibodies against membrane antigens of isolated rabbit hepatocytes and in vivo fixed IgG on their hepatocellular plasma membranes. The results suggest the existence of autoantibodies against hepatocellular membrane antigens. In addition, immune complexes may be bound to the plasma membranes. The pathogenetic role of these humoral immune reactions has yet to be determined.

Detection of a liver-membrane autoantibody in HBsAg-negative chronic active hepatitis

Investigation of humoral immunity against hepatocellular membrane antigens in patients with chronic active hepatitis and other liver diseases showed two different immunofluorescence patterns of IgG on hepatocyte membranes. A linear pattern was seen in HBsAg-negative hepatitis, but HBsAg-positive cases and some of protracted, acute hepatitis B had a granular pattern. In patients with IgG bound to hepatocytes, continuing necrosis of parenchymal liver cells was seen. Conversely, hepatocytes without bound IgG were found in cases of chronic active hepatitis in remission, acute viral hepatitis without HBsAg and chronic persistent hepatitis, in "healthy" HBsAg-carriers and in patients with fatty liver or alcoholic cirrhosis. A liver-membrane autoantibody in serum, proved by fixation on membranes of isolated rabbit hepatocytes, could be demonstrated only in HBsAg-negative chronic active hepatitis with elevated IgG-concentrations. The results support the existence of different pathogenetic types of chronic active hepatitis, a so-called autoimmune type and a hepatitis virus-B-induced type.

Studies on the pathogenesis of chronic inflammatory liver diseases. I. Membrane-fixed IgG on isolated hepatocytes from patients

Membrane-fixed IgG on isolated hepatocytes from biopsy material could be demonstrated by direct immunofluorescence in nine of thirty-four patients with acute virus-B hepatitis and in seventeen of forty-nine cases with chronic active hepatitis (CAH). Patients with acute virus-A hepatitis, chronic persistent hepatitis (CPH) or metabolic liver diseases did not show this phenomenon. Cases with CAH and IgG on the hepatocytes-HBsAg-positive as well as HBsAg-negative-had high inflammatory activity. Antibodies against HBsAg were not present in any serum. Autoimmune phenomena (antibodies against smooth muscle, mitochondria and nuclei) were only rarely demonstrable. The findings suggest that an antibody- or immune complex-mediated lymphocyte cytotoxicity may be involved in the pathogenesis of chronic liver diseases.

[Investigations concerning the fixation of hepatitis B-antigen (HBAg) on peripheral lymphocytes and isolated hepatocytes in patients with inflammatory liver diseases. (author's transl)]

The fixation of HBAg on lymphocytes was investigated in 127 patients with various inflammatory liver diseases. The fixation of HBAg on lymphocytes and isolated hepatocytes as well as the fixation of IgG on isolated hepatocytes were studied in 60 cases. Membrane-fixed HBAg could in no case be demonstrated on isolated hepatocytes whether these cells were derived from patients with or without HBAg in the serum. HBAg on hymphocytes was detectable in most cases of acute hepatitis during the phase when HBAg disappeared from the serum. HBAg on lymphocytes was detectable in most cases of acute hepatitis during the phase when HBAg disappeared from the serum (time of immunoelimination). Membrane-fixed IgG could be mainly demonstrated in HBAg positive acute hepatitis with a protracted course or in HBAg-positive active chronic hepatitis and signs of inflammatory activity. The results obtained for HBAg-carriers indicate (a) an immunological tolerance against HBAg, (b) a persistance of the virus infection in liver cells, and (c) an antibody-mediated cyto- and histotoxicity as a pathogenetic principle for the course of certain chronic liver diseases. The antigenic determinant of the membrane-fixed antibody is not known until now.

Studies on the pathogenesis of experimental chronic active hepatitis in rabbits. I. Induction of the disease and protective effect of allogeneic liver specific proteins

By long-term immunization intraperitoneally over 143 weeks with human liver specific proteins (HLP) together with complete Freund's adjuvant a chronic active hepatitis (CAH) was produced in rabbits, and the protective effect of allogeneic liver specific proteins (RLP) against the development of liver lesions was tested. The animals (white New Zealands) were divided into 6 groups. Immunization with HLP caused in all animals the development of CAH or liver cirrhosis, depending on the antigen dose. An autoimmunity against liver antigens, induced by HLP, persisted by immunization with RLP. The combined application of HLP and RLP (native and aggregate free, respectively) caused the development of histologically demonstrable liver lesions in only 13% of the animals. Underlying the pathogenesis of the experimental CAH is, according to the existing results, a cellular cytotoxicity. This concept is supported by the protective effect of RLP on cellular immune reactions against RLP and the induction of liver lesions. The importance of an antibody mediated cellular cytotoxicity for the pathogenesis of the experimental CAH has to be clarified by further experiments.

Liver-specific antigens of different species. II. Localization of a membrane antigen at cell surface of isolated hepatocytes

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