Hütteroth Th

Cellular cytotoxicity against autologous hepatocytes in acute and chronic non-A, non-B hepatitis.

In a microcytotoxicity assay we tested lymphocyte cytotoxicity against autologous hepatocytes. The following cytotoxicity values were found (given mean +/- SEM): acute non-A, non-B (NANB) hepatitis 45.7 +/- 4.3% (n = 7), chronic NANB hepatitis 32.8 +/- 5.1% (n = 11), chronic active hepatitis B (CAH-B) 27.7 +/- 6.7% (n = 10), toxic lesions 18.1 +/- 4.2% (n = 18), controls with normal liver histology or minimal changes 4.9 +/- 2.5% (n = 8). Thus our study shows enhanced cellular cytotoxicity in acute and chronic NANB hepatitis and indicates that T cells as well as non-T cells have cytotoxic effector functions. These findings are similar to those obtained in CAH-B and suggest that cellular immune reactions play an important role in the course of NANB hepatitis. For comparison we tested cytotoxic reactions in toxic lesions. They were only moderate and well distinguishable from those observed in NANB hepatitis and CAH-B; they even may be unspecific. No correlation was seen between cytotoxicity and aminotransferase concentrations.

HBsAg Clearance in Patients with Long-Standing Chronic Active Hepatitis B and Hepatitis B Virus-Induced Liver Cirrhosis

During a period of 3 years we observed 5 patients with chronic active hepatitis B and 2 with hepatitis B virus-induced liver cirrhosis who cleared HBsAg from their sera after 2-14 years of HBsAg carriership. 4 of them developed anti-HBs. After HBsAg clearance there was no evidence of persisting inflammatory activity within their livers. 5 of the 7 patients had been treated for 1-39 months with prednisolone, sometimes in combination with azathioprine. This therapy, however, had been stopped more than 3 years before these patients terminated their HBsAg carriership. Our observations indicate that even after long-standing chronic active hepatitis B or hepatitis B virus-induced liver cirrhosis HBsAg may be eliminated in a considerable number of patients.

Discontinuation of immunosuppressive therapy in hepatitis B surface antigen-positive chronic hepatitis: effect on viral replication and on liver cell damage.

Immunosuppressive therapy was stopped in 12 individuals positive for hepatitis Be antigen (HBeAg) and hepatitis B surface antigen (HBsAg) and in 4 individuals positive for HBsAg but negative for HBeAg. Discontinuation of immunosuppressive therapy in HBeAg-positive patients was always associated with a bout of hepatitis and elimination of HBeAg in 8/12 patients. One patient died from liver failure and 2 patients experienced a decompensation of their liver disease indicating that this approach might be harmful if used therapeutically. A bout of hepatitis was not noted in any of the individuals negative for HBeAg when the immunosuppressive therapy was stopped, implying that this event is not potentially harmful to the patient.

Treatment of hepatitis B surface antigen (HBsAg)-positive chronic hepatitis with recombinant leucocyte α-A interferon

A total of 32 individuals with HBsAg-positive and anti-delta-negative chronic hepatitis were treated with recombinant alpha-A interferon in phase I and phase II studies. In 5/32 patients HBsAg could be eliminated and in 19/32 individuals HBeAg became negative including all those who also eliminated HBsAg. Side-effects were tolerable in most patients and were readily reversible upon discontinuation of interferon therapy. In conclusion, treatment of HBsAg-positive chronic hepatitis with interferon seems to be a promising therapeutic approach. Future studies will have to establish the optimal dose, duration of treatment and factors predicting a favourable outcome of the treatment.

Liver cell damage caused by monoclonal antibody against an organ-specific membrane antigen in vivo and in vitro

Monoclonal antibodies have been raised against different antigenic determinants of normal rabbit hepatocytes. One antibody (2D3) recognized a liver-specific 43 kDa protein displayed exclusively on the basolateral portion of the hepatocellular membrane. Purified monoclonal antibodies were injected intravenously into rabbits. Following the injection of antibody 2D3, a dose-dependent increase of liver enzyme activities in sera was observed. Within 8 h, marked morphological alterations of the hepatocytes, including multiple cell necroses, could be demonstrated by light and electron microscopy. When isolated vital rabbit hepatocytes in culture were used as targets, cytotoxic effects of this antibody could also be observed. This indicates that liver cell damage was not due to antibody-dependent cellular cytotoxicity, but was mediated by the antibody itself. Control antibodies did not show these effects. Thus, our results clearly demonstrate that humoral immune reactions against particular liver membrane antigens may play a role in the development of liver diseases, and provide a useful experimental approach for the investigation of their specificity.

Analysis of liver-specific protein LSP using murine monoclonal antibodies.

Abstract. We describe twenty murine monoclonal antibodies directed against different antigenic determinants of human and rabbit liver‐specific protein LSP. Among them, nine were directed against liver‐specific epitopes as judged from immunohistological studies. Immunoelectronmicroscopy revealed that seven of these monoclonals recognized membrane determinants differing in staining of distinct areas of the hepatocellular surface. Eleven antibodies were directed against intracellular structures. Western blot analysis showed that the epitopes detected were displayed on either single or multiple protein bands with apparent molecular weights between 24 000 and 60 000. Further differences were observed with respect to the species specificity and (among the non‐organspecific antibodies) pattern of tissue cross‐reactivity. Our results demonstrate the presence of several liver‐specific determinants and membrane components within LSP. There are, however, a very much greater number of non‐organ‐specific epitopes and numerous determinants displayed on intracellular structures. This emphasizes the remarkable heterogeneity of the antigen preparation named LSP and warrants the use of clearly defined antigens in further studies dealing with auto‐immune phenomena in liver diseases.

Antigenic relationship between Chang liver cells and human hepatocytes

ZusammenfassungMit Hilfe monospezifischer Antiseren gegen menschliches lebermembranspezifisches Protein (LSP) konnte gezeigt werden, daß Chang Leberzellen LSP auf der Zellmembran besitzen. Chang Leberzellen können daher als in vitro System zur Untersuchung immunologischer Reaktionen gegen LSP in menschlichen entzündlichen Lebererkrankungen benutzt werden.SummaryUsing monospecific antisera against human liver specific protein (LSP) it could be demonstrated that Chang liver cells bear LSP on their membranes. Chang liver cells can therefore be used as in vitro system to study immune reactions against LSP in human inflammatory liver diseases.

Monoclonal Antibodies as Probes to Define Critical Surface Structures Involved in T Cell Activation

The production of monoclonal antibodies directed against surface structures of human T lymphocytes has provided unique probes to define discrete stages of T cell differentiation as well as individual T cell subpopulations that are programmed to perform regulatory and effector functions in the immune response (1–3). Importantly, besides their usefulness for phenotypic characterization of normal and malignant cells of the T lineage, these reagents have also been employed to characterize the physiologic role of their respective membrane molecules. For example, it was possible to identify by monoclonal antibodies the transferrin receptor (4), the receptor for interleukin-2 (5), and, more recently, the T cell antigen receptor (6). Moreover, on the basis of functional antibody effects in vitro, it was suggested that the subset restricted glycoproteins, T4 and T8, are themselves involved as associative recognition structures for constant portions of, respectively, class II or class I MHC gene products in effector—target cell interaction (7). This view originated from studies in which antibodies were utilized to block in vitro responses such as cytotoxicity or/and proliferation (8,9,10).

Characterization of Circulating Immune Complexes in Chronic Non-A, Non-B Hepatitis

We studied the frequency and composition of circulating immune complexes (CIC) in patients with chronic persistent non-A, non-B (NANB) hepatitis and in convalescent persons after an apparently normal recovery from acute NANB hepatitis. 10 of 16 patients with chronic NANB hepatitis and 5 of 11 convalescent persons after acute NANB hepatitis had CIC as detected by the Raji cell technique. CIC in chronic NANB hepatitis were composed of IgG, C3, and in 7 of 10 cases also IgM, while in CIC from convalescent persons IgG and C3 were present, too, but IgM was detected in only 1 case. Viral antigens within the CIC were not detectable in any case while 14 of 16 chronic NANB hepatitis patients were found to have free virus-associated antigen in serum.

Kooperative prospektive Studie „Akute Virushepatitis“ (DFG)

Motiv fur die 1972 begonnene prospektive DFG-Studie „Akute Virushepatitis“ war ursprunglich die Abklarung der diagnostischen und prognostischen Bedeutung des ersten HBV-Markers, des Australia-Antigen (= HBsAg). Insbesondere sollte die Spatprognose von HBsAg-positiver und-negativer Hepatitis verglichen werden. 1976 konnte ich an gleicher Stelle in einem ersten Zwischenbericht [1] mitteilen, das sich ein Jahr nach akuter HBsAg-positiver Virushepatitis mit 8,5% ebenso haufig gesicherte chronische Verlaufe fanden wie nach HBsAg-negativer Hepatitis (8,6%). Bereits damals wurde vermutet und heute ist erwiesen, das sich die HBsAg-negative Gruppe aus A-, Non-A, Non-B- und einem kleinen Anteil von HBsAg-negativen B-Hepatitiden zusammensetzt. Aufgrund der Planung der Studie mit Anlage einer Serumbank und der weiteren Entwicklung der Virusserologie mit der Moglichkeit zur Differenzierung von Hepatitis A und — vorerst per exclusionem — Non-A, Non-B sind heute Aussagen zu erweiterten Fragestellungen moglich: 1. Abgrenzung von Virushepatitiden unterschiedlicher atiologie: A; B; Non-A, Non-B. 2. Haufigkeit der Entwicklung einer chronischen Hepatitis in Abhangigkeit von der atiologie. 3. Die Bedeutung virusserologischer Parameter der Hepatitis B fur die fruhe Prognosestellung. 4. Besonderheiten des Krankheitsverlaufes bei akuter Virus-Hepatitis unterschiedlicher Atiologie.