IgG subclass distribution of autoantibodies to glomerular basement membrane in Goodpasture's syndrome compared to other autoantibodies

The IgG subclass distribution of autoantibodies to glomerular basement membrane (anti-GBM antibodies) was investigated and compared to the distribution of liver-kidney microsomal (LKM) autoantibodies in chronic active hepatitis, to antimitochondrial autoantibodies (AMA) in primary biliary cirrhosis, and to the subclass distribution of total serum IgG within a healthy population. Solid phase assays for the demonstration of these autoantibodies were performed with four mouse monoclonal antibodies specific for each human subclass to provide quantitative data for the autoantibodies. In addition, the subclass distribution of total IgG in these sera was analyzed. IgG1 accounted for 75% of the total antibody activity in anti-GBM antibodies. In LKM antibodies a more homogeneous distribution was observed between the different subclasses with a relative high proportion of IgG4 autoantibodies (21.2%). In AMA a high proportion of IgG3 subclass autoantibodies was found (anti-p-48 = 28.7%, anti-p-62 = 29.9%). In these patients a high proportion of IgG3 (23 vs. 27.2%) could also be demonstrated in the subclass distribution of total IgG, whereas in patients with anti-GBM antibodies and LKM antibodies the subclass distribution of total IgG was comparable to a population of healthy volunteers. We conclude that the subclass distribution in anti-GBM antibodies differs from the distribution in other autoimmune diseases and from a healthy population and that these differences may be of pathogenetic relevance.

Expression of Pre-S-encoded proteins in sera of individuals chronically infected with hepatitis D virus

The sera of 16 individuals chronically infected with the hepatitis D virus were analyzed for hepatitis B virus (HBV) markers. The majority of these patients had a non-replicative form of viral type B hepatitis as indicated by negative tests for HBeAg and HBV-DNA. Pre-S-encoded proteins were detected in 13/16 sera. Sera that were negative for polymerized serum albumin did also not contain pre-S1-encoded proteins. The presence of pre-S-encoded proteins is probably predominantly associated with 22-nm HBsAg forms present in large amounts in sera of individuals with chronic type D hepatitis.

Distinction between natural and pathological autoantibodies by immunoblotting and densitometric subtraction: liver-kidney microsomal antibody (LKM) positive sera identify multiple antigens in human liver tissue

Using one-dimensional and two-dimensional immunoblotting techniques the reactions of sera from 14 patients with liver-kidney microsomal (LKM) antibody positive chronic active hepatitis (CAH) with human liver microsomal preparations was compared with the reaction of sera from 12 healthy persons and from five patients with systemic lupus erythematosus (SLE). All sera displayed a multiplicity of reactions. This demonstrates the presence of many autoantibodies in normal human sera. It could be shown that all sera react with the cytoskeletal antigens cytokeratin, actin and actomyosin. These reactions were more marked in the autoimmune sera, i.e. LKM-positive CAH and SLE. Densitometric subtraction was found to be a reliable technique to distinguish the natural antigen/autoantibody reactions from pathological, disease-characteristic autoantibodies. It was shown that the pathological LKM autoantibodies recognize non species-specific microsomal proteins at 50 kD of pI 7.5-8.0 at high titres, which are only very weakly recognized by normal or SLE sera. We recommend sensitive immunoblotting techniques and densitometric subtraction as the currently most accurate method to distinguish natural from pathological autoantibodies.

Relationship of pre-S encoded antigens in liver and clinical manifestations of chronic hepatitis B infection

Pre-S1 and pre-S2 encoded antigens of hepatitis B virus were localized in liver tissue using monoclonal antibodies. They were found to be exclusively expressed in the cytoplasm of liver cells. Cell bound pre-S1 encoded protein was often detected in patients with chronic liver disease and viremia. Only a small number of the HBsAg positive cells also contained pre-S1 antigen. There was no correlation with nuclear HBcAg. Livers of non-viremic HBsAg carriers contained many HBsAg expressing liver cells, that were frequently also positive for pre-S2 encoded protein but contained no detectable pre-S1 encoded protein at all. It remains open whether cell bound pre-S2 containing proteins of middle size have a significance for pathogenesis, as they are present in individuals with chronic liver disease as well as in healthy HBsAG carriers, and may be associated with both increased and normal liver enzymes. Cell bound pre-S1 antigen with viremia may, however, be involved in the maintenance of viremia and liver disease.

Two different subtypes of antimitochondrial antibodies are associated with primary biliary cirrhosis: identification and characterization by radioimmunoassay and immunoblotting

Antimitochondrial antibodies from patients with primary biliary cirrhosis react with different mitochondrial polypeptides as demonstrated by Western blots. The IgG fractions of a patient with primary biliary cirrhosis Stage I reacting exclusively with a pair of polypeptides at 48,000 daltons (p 48) on Western blot and from a patient with Stage III primary biliary cirrhosis reacting exclusively with a single 62,000 dalton polypeptide (p 62) were labeled with 125I; two radioimmunoassays were established detecting antimitochondrial antibodies against p 62 and p 48, respectively. Autologous sera blocked the assay, but the two reference sera did not block each other. Fourteen of 40 patients with primary biliary cirrhosis reacted with p 62, 6/40 with p 48 and 20 sera with both antigens. Sera from 200 patients with various hepatic and nonhepatic diseases were negative for anti-p 62 and anti-p 48. This collection of sera included 5 patients with nonhepatic autoimmune disorders, 3 with drug-induced pseudolupus syndrome and 2 with syphilis II, which were positive for antimitochondrial antibodies by immunofluorescence. Mitochondrial autoantigens p 62 and p 48 were both localized on mitoplasts, presumably inner mitochondrial membranes; they were thermolabile, trypsin- and chymotrypsin-sensitive, but resistant to DNAase, RNAase and neuraminidase treatments. In cesium chloride density gradients, p 62 floated at 1.28 gm per cm3 and p 48 at 1.30 gm per cm3. Thus, radioimmunoassays have been developed that specifically detect two distinct primary biliary cirrhosis-specific subtypes of antimitochondrial antibodies: anti-p 62 and anti-p 48. All primary biliary cirrhosis sera were positive for at least one of these antimitochondrial antibodies subtypes.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of liver-specific protein LSP using murine monoclonal antibodies

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-organ-specific 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.

Liver membrane autoantibodies in chronic active hepatitis. Studies on mechanically and enzymatically isolated rabbit hepatocytes

Target antigens relevant for immune reactions in inflammatory liver diseases should be expressed on the hepatocellular membrane. Using mechanically or enzymatically isolated rabbit hepatocytes, we evaluated the influence of cell integrity on the detection of membrane-expressed antigens by sera from patients with chronic hepatitis and by murine monoclonal antibodies. Our results provide evidence that target antigens of liver membrane autoantibodies (LMA) as well as liver kidney microsomal antibodies (LKM) are not expressed on the hepatocellular membrane of viable and intact isolated rabbit hepatocytes. However, LMA were detected in the sera of 56% of patients with autoimmune chronic active hepatitis using mechanically isolated hepatocytes. These findings underline the diagnostic relevance of the autoantibodies. It is suggested that LMA are directed against constituents of the cytoskeleton. Therefore, it seems to be unlikely that this antibody is causally involved in the pathogenesis of autoimmune liver diseases.

The effect of recombinant alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins in man

The effect of alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins was analyzed in eight patients with chronic type B hepatitis who participated in a pilot study of interferon therapy. Three individuals became HBsAg-negative, 4 lost HBeAg but remained HBsAg-positive and 1 remained positive for both HBsAg and HBeAg. Initiation of interferon treatment was rapidly followed by reduction or loss of hepatitis B virus DNA in the serum but by little immediate change in hepatitis B virus antigen levels. Changes in hepatitis B virus antigens were usually delayed. Loss of HBsAg from the serum was preceded by the sequential disappearance of pre-S-encoded proteins (pre-S1 and polymerized human serum albumin) and HBeAg. In patients who lost HBeAg but remained HBsAg-positive, serum levels of pre-S1 and polymerized human serum albumin usually, but did not always, decrease. The individual who remained HBsAg- and HBeAg-positive had unchanged serum levels of pre-S1, polymerized human serum albumin and HBsAg. These results suggest that alpha-interferon inhibits hepatitis B virus DNA replication but has little direct effect on synthesis of hepatitis B virus gene products.

Pre-S encoded surface proteins in relation to the major viral surface antigen in acute hepatitis B virus infection

The role of pre-S encoded viral surface proteins in acute hepatitis B virus infection is still poorly understood. Binding sites for polymerized human serum albumin have been found to be encoded by the pre-s2 region of the hepatitis B virus genome. Recently, murine monoclonal antibodies against pre-s1 and pre-s2 encoded hepatitis B virus gene products were generated and used for their specific detection in serum. In sera from patients with acute hepatitis B, pre-s1 and pre-s2 antigen occurred in 16 of 20 and 15 of 20 patients, respectively. In the initial stage of the disease, pre-S gene products correlated with binding sites for polymerized human serum albumin, but not with hepatitis B surface antigen. Subsequently, pre-s1 and pre-s2 antigens were cleared from the serum of patients with acute hepatitis B before binding sites for polymerized human serum albumin and hepatitis B surface antigen. Possibly, the early clearance of pre-S markers can be of prognostic value in acute hepatitis B. The mechanisms of the early clearance of the pre-S antigens in acute hepatitis B remain to be elucidated. However, elimination by immunologic mechanisms appears likely.

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.

Characterisation of a new subgroup of autoimmune chronic active hepatitis by autoantibodies against a soluble liver antigen

Autoantibodies against a soluble liver antigen (SLA) were detected in 23 patients with HBsAg-negative chronic active hepatitis (CAH) but not in 502 patients with various other hepatic and non-hepatic disorders or 165 healthy blood donors. Anti-SLA-positive serum samples were negative for antinuclear and liver-kidney-microsomal antibodies, markers of two subgroups of autoimmune-type CAH, 6 anti-SLA-positive patients were negative for all autoantibodies sought. Most of the anti-SLA-positive patients were young women (2 men, 21 women; mean age 37 years) with hypergammaglobulinaemia (mean 3.2 g/l, range 1.8-5.3 g/l); 18 of the 23 patients had received immunosuppressive treatment and all responded well. Anti-SLA titres declined during therapy, corresponding to disease activity. Anti-SLA cannot be detected by immunofluorescence. SLA is not organ-specific or species-specific, but the highest concentrations were found in liver and kidney. Anti-SLA autoantibodies characterise a third subgroup of autoimmune-type CAH and will allow a better differentiation of HBsAg-negative CAH which has therapeutic consequences.

Identification of Goodpasture target antigens in basement membranes of human glomeruli, lung, and placenta

Collagenase-digests of human glomerular (GBM), alveolar (ABM), and placenta basement membranes (PBM) were separated by gel filtration columns and the pools rich in Goodpasture antigens (GP) were identified by an antibody inhibition-ELISA. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting on nitrocellulose membranes was performed with each basement membrane preparation. Sera from patients with florid GP-syndrome and antibodies to glomerular basement membrane (anti-GBM antibodies) were incubated with nitrocellulose strips of GBM, ABM, and PBM. Immunoperoxidase staining revealed reactivity with target antigens of 24, 26, 44, and 50 kD in the GBM and of 44 and 50 kD in the ABM and PBM, respectively. No corresponding reactivity was observed using convalescent GP-sera, sera from patients with other immunological diseases or sera from healthy blood donors. The antigens were sensitive to reduction. We conclude, that antigens of similar molecular-weights can be identified by anti-GBM positive sera in human glomerular, alveolar and placenta basement membranes.

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.

Virus-associated receptors for polymerized human serum albumin (RpHSA) in patients with chronic active hepatitis B treated with recombinant leukocyte A interferon

Hepatitis B surface antigen (HBsAg)-associated receptors for polymerized human serum albumin (RpHSA) are assumed to mediate viral attachment to hepatocytes in hepatitis B virus (HBV) infection. RpHSA was found to be coded by the pre-S region of HBV genome. Recently, the antiviral effect of recombinant leukocyte alpha-interferon was shown in patients with hepatitis B. Our study evaluated the detection and the clinical implications of RpHSA in patients with chronic active hepatitis B under treatment with recombinant alpha-interferon. Two out of nine patients eliminated all HBV markers including RpHSA. Four out of nine patients became negative for markers of viral replication but remained positive for HBsAg and in part for RpHSA. In three out of nine patients HBV markers including RpHSA remained unchanged. In summary, the titer for RpHSA is a reliable indirect marker for infectivity and of prognostic value in patients with chronic active hepatitis B during interferon treatment. Future studies should evaluate a putative immune response to RpHSA-containing viral surface proteins, which could be relevant for viral clearance in HBV infection.

Subtypes of antimitochondrial antibodies in primary biliary cirrhosis before and after orthotopic liver transplantation

Antimitochondrial antibodies are markers for primary biliary cirrhosis and probably reflect a specific defect in immunoregulation underlying this disease. Antimitochondrial antibodies and their primary biliary cirrhosis-specific subtypes were tested before and up to 6 years after orthotopic liver transplantation. Sera from 31 consecutive patients were tested, 15 patients had primary biliary cirrhosis and 16 non-primary biliary cirrhosis. Antimitochondrial antibodies were investigated under code by immunofluorescence, and primary biliary cirrhosis-specific subtypes were determined by radioimmunoassay (anti-p62, anti-p48) and complement fixation test (anti-M2, anti-M4, anti-M8). Before orthotopic liver transplantation, antimitochondrial antibodies were detected by immunofluorescence in 13 of 15 patients with primary biliary cirrhosis. Of these patients, 12 were positive for anti-p62 and 8 for anti-p48. Ten patients were positive for anti-M2, 4 patients for anti-M4 and 7 patients for anti-M8. Two primary biliary cirrhosis patients and all non-primary biliary cirrhosis patients were negative with all tests. One month after orthotopic liver transplantation, antimitochondrial antibodies titers declined or became negative by antimitochondrial antibodies immunofluorescence, 3 patients became negative by radioimmunoassay for anti-p62 and 1 for anti-p48. With complement fixation test, 4 patients became negative for anti-M2, 2 for anti-M4 and 4 for anti-M8. Antimitochondrial antibody titer reduction observed 1 month after orthotopic liver transplantation remained unchanged in most sera during the following years. A rise was observed in two patients after 4 and 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of hepatitis B virus markers in sera of asymptomatic hepatitis B surface antigen carriers with special emphasis to pre-S-encoded proteins

Sera of asymptomatic hepatitis B surface antigen (HBsAg) carriers were analyzed for the presence of pre-S-encoded proteins. Four individuals with biopsy-proven chronic hepatitis uniformly expressed pre-S1- and pre-S2-encoded proteins. Individuals who had histologically normal or largely normal livers were heterogeneous with respect to expression of pre-S-encoded proteins. This heterogeneous expression of pre-S-encoded proteins occurred most likely due to difference in serum HBsAg concentration. Alternatively differences in pre-S gene expression need to be considered. Clinically the study indicates that expression of pre-S domains in serum is unrelated to viremia or chronic liver disease.

[Acute fatty liver of pregnancy. A case report of the differential diagnosis of pregnancy-associated liver diseases]

Acute fatty liver of pregnancy (AFLP) is a rare, but often fatal disorder in the third trimester of pregnancy. We report on a patient with AFLP complicated by acute hemorrhagic diathesis, who survived after early diagnosis and adequate treatment. On electronmicroscopy, the characteristic microvesicular fatty deposits in the centrolobular hepatocytes could be demonstrated.

[Myxoma of the right atrium. Rare differential diagnosis of fever of unknown origin]

Cholecystectomy had been performed in a 52-year-old woman because of upper abdominal pain with nausea, fever and accelerated ESR and known cholelithiasis. Attacks of fever up to 39.5 degrees C persisted and she lost 10 kg in weight, requiring re-admission after eight months. Transoesophageal echocardiography revealed an echo-dense space-occupying lesion, 3.0 X 3.5 cm, in the right atrium. Due to contrast medium allergy angiography was omitted. M-mode and 2D echocardiography and computed tomography of the heart failed to demonstrate any space-occupying body. Thoracotomy revealed a fibro-angio-myxoma attached to the right side of the interatrial septum, and it was removed in toto. The postoperative course was without complications and the patient left hospital free of symptoms. It is suggested that transoesophageal echocardiography should be considered in case of "fever of unknown origin".

[Neurocysticercosis. Diagnostic and therapeutic advances]

A 42-year-old man of Croatian birth, with long-standing neurological symptoms, was found to have neurocysticercosis (a rare disease in Central Europe), as proven by positive antibody titres in serum and CSF and typical foci by computed tomography (CT). Ventriculo-cisternal drainage (after Torkildsen) controlled the acute symptoms of raised intracranial pressure. Postoperatively the CT revealed new low-density intracerebral foci, which responded to praziquantel.

Effect of modern analgesic drugs (tramadol, pentazocine, and buprenorphine) on the bile duct sphincter in man

Modern narcotic analgesic drugs, such as tramadol, pentazocine, and buprenorphine share similarities of molecular structure with morphine which is widely believed to cause spasm of the bile duct sphincter and so impede bile flow. This study assessed the effects of intravenously administered analgesics on bile duct sphincter motor activity measured by ERCP manometry. Ten minutes after pentazocine injection the duration of contractions and baseline pressure of the bile duct sphincter rose from 6.2 +/- 0.2 to 8.2 +/- 0.27 s and from 5.1 +/- 0.6 to 8.8 +/- 0.4 mmHg respectively. Tramadol, buprenorphine and saline showed no such effect. These data indicated that the effects of such drugs on bile duct sphincter function can be safely assessed by ERCP manometry and that pentazocine adversely affects the bile duct sphincter, whilst tramadol and buprenorphine do not. We consider therefore that pentazocine is not the premedication of first choice for endoscopic procedures involving the sphincter of Oddi and should also be avoided in patients with pancreatic and biliary disorders.