Antibodies to liver/kidney microsome1 in chronic active hepatitis recognize specific forms of hepatic cytochrome P-450

Anti-liver/kidney microsome1-positive sera from children with chronic active hepatitis were studied in an effort to identify the microsomal antigens selected during induction and progression of this autoimmune disease. Immunoblot analysis of sodium dodecyl sulfate gel-resolved microsomal proteins from human and rat liver using anti-liver/kidney microsome1-positive sera revealed a single polypeptide of 48 kilodaltons (human microsomes) or 50 kilodaltons (rat microsomes). Levels of the 50-kilodalton rat microsomal polypeptide were suppressed in vivo by several drugs known to modulate expression of individual forms (enzymes) of hepatic cytochrome P-450, with the largest decrease effected by phenobarbital. Dot blot analysis using a panel of 10 electrophoretically homogeneous rat liver cytochrome P-450 forms under nondenaturing conditions established that the two methylcholanthrene-inducible forms, P-450 BNF-B and P-450 ISF-G (P-450 gene subfamily IA), are selectively recognized by the anti-liver/kidney microsome1 antibodies. These findings demonstrate that sera associated with autoimmune (anti-liver/kidney microsome1) chronic active hepatitis are specifically reactive with select rat hepatic P-450 forms and suggest that these autoantibodies may be principally directed against one or more constitutive forms of the corresponding human liver cytochromes.

Anti-liver kidney microsome antibody recognizes a cytochrome P450 from the IID subfamily

Children with autoimmune hepatitis have high serum titers of antibodies directed against a 50-kD protein of rat liver endoplasmic reticulum. Affinity-purified anti-50-kD antibodies were used to screen a rat liver cDNA library in lambda GT-11 expression vector. 12 immunopositive clones were obtained. Crossreactivities between fusion proteins of these clones and the 50-kD protein was demonstrated, and four clones were analyzed by restriction mapping, one of them by nucleotide sequencing. Complete identity was found between the restriction maps of two clones (LKMC1 and LKMC2) and that of the 5' end of the rat cytochrome P450 db2. Sequence of a 608-bp fragment of LKMC1 showed complete homology with the rat P450 db2 form. The restriction map of the other two clones (LKMC3 and LKMC4) was identical to that of rat P450 db1. These results suggest that the antigen recognized by LKMA is a P450 of the IID subfamily.

Counterimmunoelectrophoresis (CIE) for the detection of anti-liver-kidney microsome (LKM) antibodies in the sera of patients with chronic liver disease

A counterimmunoelectrophoresis (CIE) test for the detection of liver-kidney microsome specific antibodies in human sera is described. By testing different subcellular preparations the LKM antigen was found in the membranes of the smooth endoplasmic reticulum subfraction. The antigen was sensitive to trypsin digestion and behaved as an anionic protein in the experimental conditions used in the test. All sera positive for LKM in immunofluorescence gave a precipitin line of identity while none of the control sera gave a positive reaction. The CIE titers ranged between neat and 1/4096. A significant correlation was observed between the LKM titers obtained in immunofluorescence and those obtained in CIE. Moreover, by absorption experiments, it was concluded that the antigen preparation reactive in CIE was able to abolish the immunofluorescence pattern of LKM positive sera on rat liver and kidney sections. The LKM target antigen, although previously considered a structural protein of microsomal membranes, was shown to solubilize spontaneously during the isolation of microsomal membranes. Counterimmunoelectrophoresis appears to be an appropriate test for anti-LKM antibodies in human sera.

Does the immune response play a role in the pathogenesis of chronic liver disease?

The pathogenesis and perpetuation of hepatocellular injury in chronic inflammatory liver disease is still unclear. Several pieces of circumstantial evidence point to the importance of antigen-specific immune responses. In chronic hepatitis B virus infection, the hepatitis B virus nucleoprotein appears to be a major target antigen for both helper and cytotoxic T lymphocytes. In autoimmune chronic active hepatitis, several autoantibodies have been identified that are associated with different disease subgroups and that may be helpful to distinguish this form of chronic active hepatitis from that caused by non-A, non-B agents. In primary biliary cirrhosis, antimitochondrial antibodies are almost invariably present and have now been characterized at the molecular level.

Electrophoretic protein blots as aids in choosing fixatives for immunocytochemistry

We used electrophoretic protein blots prepared from polyacrylamide gels to test the effect of different fixatives on the antigenicity of rough endoplasmic reticulum (RER) peptides from rat liver. Protein blots were prepared by the procedure of Towbin et al. (Proc Natl Acad Sci USA 76:4350, 1979), treated with different fixatives, rinsed to inactivate non-specific reactive sites, and then reacted with rabbit polyclonal anti-rat liver RER antibodies, followed by peroxidase-conjugated anti-rabbit antibodies. On the basis of differences in immunostaining densities as determined by densitometry, we found that RER peptides displayed differential sensitivities to various fixatives. Anti-rat liver RER antibodies and the immunogold technique were applied to methacrylate sections of in vitro fixed rat liver rough microsomes. Specific labeling was observed over the microsomes and was shown by quantitation to vary in a similar manner to the immunostaining of specific peptides in protein blots following different fixations. We conclude that protein blots may serve as useful tools for screening the effects of different fixatives on cell antigenicity, and therefore may be helpful in immunocytochemical studies.

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.

Chronic active hepatitis associated with antiliver/kidney microsome antibody type 1: a second type of "autoimmune" hepatitis

Sixty-five patients with histologically proven chronic active hepatitis of unknown cause but associated with the antiliver/kidney microsome antibody type 1, confirmed by immunofluorescence and immunoprecipitation, were selected as forming a special entity. This disease was found to be rare with a prevalence of 5/1,000,000. The female to male ratio was 8:1. The condition occurred at all ages but was most common between the ages of 2 and 14 years. In 22 of the 65 cases, the hepatitis was associated with an autoimmune disease, most commonly insulin-dependent diabetes, autoimmune thyroid disease and vitiligo. The same autoimmune diseases were present in first-degree relatives from seven families. In 36 cases, the onset of disease resembled acute viral hepatitis. Serum biochemical tests showed marked elevation in aminotransaminases and hypergammaglobulinemia. Paradoxically, serum and salivary IgA levels were often normal or low. Histologic findings were multifocal hepatic necrosis with bridging in the acute stage, and aggressive hepatitis with mononuclear cell infiltration or macronodular cirrhosis in the late stages. Serologically, apart from the presence of antiliver/kidney microsome antibody type 1, the disease was characterized by the absence of antiactin, antimitochondria and antinucleus antibodies; however, organ-specific autoantibodies were often present. The clinical course was usually severe: six patients in the acute stage presented with fulminant hepatitis, and all, except two, other patients progressed to cirrhosis. Prolonged treatment with corticosteroids and immunosuppressants was usually effective in rendering the cirrhosis inactive. The cumulative survival rate was 51% at 14 years. We propose to call this entity "anti-LKM1 chronic active hepatitis" or "autoimmune hepatitis type II" to differentiate it from classical "lupoid hepatitis" or autoimmune hepatitis type I.

Characterization of anti-liver kidney microsomal antibody in childhood autoimmune chronic active hepatitis: evidence for IgG1 subclass restriction, polyclonality and non cross-reactivity with hepatocyte surface antigens

An indirect immunofluorescence technique was used to investigate the immunoglobulin class, IgG subclass, light chain type and complement fixing ability of anti-liver kidney microsomal antibody (anti-LKM) in the sera of six children and five adults with autoimmune chronic active hepatitis (aCAH). Anti-LKM titres ranged from 1/80 to 1/20,480. In the children, the antibody belonged to the IgG1 subclass alone (titre 1/80-1/20,480) and was able to fix complement (titre 1/40-1/5120). In the adult group, antibody belonged to the IgG1 subclass in three cases (titre 1/40-1/640) whilst two belonged to both IgG1 (titre 1/640) and IgG4 (titre 1/40, 1/640). Such subclass restriction is similar to that found in other autoimmune disorders and may be genetically determined. Investigation of the light chain constituent of anti-LKM revealed that the kappa to lambda ratio was consistent with a polyclonal antibody response. To investigate the nature of the antigen to which anti-LKM is directed, the ability of these sera to bind to the surface membrane of isolated human hepatoma cells (Alexander cells) was investigated. Four of the eleven sera showed significant binding activity. Prior incubation of these four sera with Alexander cells abolished their membrane binding activity, but did not alter the anti-LKM titre. These results suggest that anti-LKM binds to cytoplasmic constituents alone and does not cross-react with surface antigens.

Heterogeneity of growth-hormone receptors detected with monoclonal antibodies to human growth hormone

The specificity of hormone-receptor interactions has been examined with the aid of monoclonal antibodies (MABs) (EB1, EB2, QA68 and NA71) defining four non-overlapping antigenic determinants on human growth hormone (hGH). The results indicate that growth-hormone receptors in liver obtained from different sources differ with regard to their affinities and relative numbers; they may also differ with respect to the region of the growth-hormone molecule to which they bind. Antibody NA71 effectively inhibited hormone binding to all receptor preparations tested, although with various degrees of potency. Monoclonal antibody EB1 demonstrated a graded inhibition with respect to its ability to block 125I-hGH binding to receptors from various sources, the maximum inhibition being seen in receptor preparations from mouse and ovine liver and the minimum in rat liver. MABs EB2 and QA68 also showed various abilities to inhibit hormone-receptor interaction, depending on the origin of the receptor preparation. Furthermore, the receptor-binding characteristics of hormone-antibody complexes were dependent on whether the binding-site preparation was derived from pregnant, lactating or 'normal' animals. A particularly striking difference between the ability of hormone-MAB complexes to bind to receptors from different sources was seen for microsomes (microsomal fractions) derived from livers of animals of the 'Little' mouse strain. These animals become progressively obese, and it was shown that MABs were considerably more effective in inhibiting 125I-labelled hGH binding to microsomes from phenotypically obese mice than to those derived from their non-obese littermates. The results can be explained by the presence of multiple receptor types for GH, the relative proportions of which vary according to the physiological state of the animal, and possibly between species.

Human anti-endoplasmic reticulum autoantibodies appearing in a drug-induced hepatitis are directed against a human liver cytochrome P-450 that hydroxylates the drug

"Anti-liver/kidney microsome" (anti-LKM) autoantibodies have been found in the serum of patients with cryptogenic chronic hepatitis and with immunoallergic drug-induced hepatitis, such as those induced by halothane or by tienilic acid (called anti-LKM2 in this case). So far the nature of the human microsomal macromolecules recognized by these antibodies has not been determined. Here we show, by using immunoblot techniques, that among the macromolecules present in human adult liver microsomes, one protein called cytochrome P-450-8 is specifically recognized by most sera of patients containing anti-LKM2 antibodies but not by control serum. Human fetal liver microsomes that do not contain cytochrome P-450-8 are not recognized by the anti-LKM2 antibodies. It is also shown that anti-cytochrome P-450-8 antibodies as well as human serum containing anti-LKM2 antibodies specifically inhibit the hydroxylation of tienilic acid by human liver microsomes. These results indicate that anti-LKM2 antibodies appearing in patients with hepatitis and concomitant administration of tienilic acid are directed against a cytochrome P-450 isoenzyme that catalyzes the metabolic oxidation of this drug. This suggests a possible mechanism for the appearance of anti-organelle antibodies in a drug-induced hepatitis.

Immunochemical characterization of human lung epoxide hydrolases

Immunochemical techniques were used to investigate the biochemical properties of human lung epoxide hydrolases. Two epoxide hydrolases with different immunoreactive properties were identified. These two epoxide hydrolases were found in both cytosolic and microsomal cell fractions. Immunotitration of enzyme activity showed that enzymes that catalyze the hydration of benzo(a)pyrene 4,5-oxide react with antiserum to rat microsomal epoxide hydrolase; those that hydrate trans-stilbene oxide do not. Immunotitration and Western blot experiments showed that microsomal and cytosolic benzo(a)pyrene 4,5-oxide hydrolases have significant structural homology. Immunohistochemical staining of human lung benzo(a)pyrene 4,5-oxide hydrolase showed that the enzyme is localized primarily in the bronchial epithelium. No cell type-specific localization was observed. An enzyme-linked immunosorbent assay was developed which allows direct quantitation of benzo(a)pyrene 4,5-oxide hydrolase protein. Levels of enzyme protein detected by this assay correlated well with enzyme levels determined by substrate conversion assays.

Immunochemical subfractionation of a microsomal fraction of rat liver with antibody-coated Staphylococcus aureus cells

The procedure for immunochemical adsorption of vesicles with specific antigen on their outer surfaces was improved. When microsomal vesicles were mixed with Staphylococcus aureus cells coated with the antibody against NADPH-cytochrome c reductase, more than 90% of the enzyme activity was adsorbed on the cell, whereas, only about 10% of the activity was adsorbed on cells coated with the same amount of anti-ovalbumin antibody. NADH-cytochrome c reductase and aldehyde dehydrogenase activities were adsorbed on the cell to the same extent as was NADPH-cytochrome c reductase activity. Under this condition, there was no adsorption of the activities of the marker enzymes of lysosomes and Golgi apparatus, whereas large amounts of the activities of the plasma membrane enzymes were adsorbed. The specific activity of NADPH-cytochrome c reductase in the adsorbed vesicles from the microsomal fractions increased considerably. In contrast, marker enzymes of the Golgi or of the plasma membranes could be enriched in unadsorbed vesicles from the Golgi fractions.

Chronic active hepatitis associated with liver-kidney microsomal antibody of an autoimmune type. Two familial cases

We report the findings in two sisters with active cirrhosis and an anti-liver-kidney microsomal antibody (anti-LKM) of the autoimmune type. This unusual disease is characterized by the presence of high levels of antibodies that react with the smooth and rough endoplasmic reticulum of the liver and other tissues. Our patients had the usual features of chronic hepatitis associated with presence of antibodies: they were young girls, they had anti-LKM antibodies of autoimmune type persisting at a high titer during the whole course of the disease, but with no smooth muscle antibodies; one had a low level of IgA. The occurrence of two cases in the same family has not yet been reported and is probably not coincidental because of the rare occurrence of this disease.

Measurement of spontaneous and stimulated anti-microsomal antibody synthesis in vitro by avidin-biotin enzyme immunoassay

The spontaneous and stimulated anti-microsomal (anti-Mic) antibody synthesis in vitro by peripheral blood lymphocytes (PBL) from patients with Hashimoto's thyroiditis (HT) was studied by a highly sensitive and thyroid microsome-specific enzyme immunoassay using an avidin-biotin system (A-B EIA). Since the amount of the synthesized anti-Mic antibody by PBL in vitro is very small, it is difficult to study its kinetics and response to mitogens or the specific antigen by conventional assay systems. We applied the avidin-biotin system to conventional indirect EIA and established an assay system which was about four times as sensitive as indirect EIA. PBL from patients with HT synthesized significant amount of IgG anti-Mic antibody spontaneously but those from normal individuals and patients with rheumatoid arthritis did not. IgG anti-Mic antibody synthesis with pokeweed mitogen stimulation was increased in all HT patients and that with thyroid microsome stimulation was increased in three out of five patients. These results indicate that A-B EIA is a useful system to study the mechanism of anti-Mic antibody synthesis in vitro.

[Determination of the monospecificity of antibodies to different forms of cytochrome p-450 using rocket immunoelectrophoresis]

Antibodies against different forms of cytochrome P-450 were analyzed, using rocket immunoelectrophoresis technique. The technique was found capable of revealing antibody monospecificity. The antibodies against a certain form of cytochrome P-450 may be regarded as monospecific when they form a single precipitation line during the analysis of microsomal preparations which contain a mixture of different forms of cytochrome P-450.

Liver disease associated with anti-liver-kidney microsome antibody in children

In the past 10 years we have examined 20 children with inflammatory liver disease associated with high serum titers of anti-liver-kidney microsome antibody (anti-LKM). The first hepatic symptoms were progressive fatigue and jaundice, the fortuitous finding of hepatomegaly or splenomegaly with raised transaminase activity, or an acute hepatitis-like illness. At the time of diagnosis, hepatomegaly was present in 18 children, splenomegaly in 16, jaundice in nine, and ascites in two. Serum alanine transferase activities were elevated in all but two, who had already received steroids. Serum total gammaglobulin values were greater than 2.0 gm/dl in 16 children, prothrombin activity less than or equal to 60% in six, and serum titer of anti-LKM between 1:100 and 1:100,000. All children but one had cirrhosis, and histologic signs of aggressivity were present in 14. In 11 children one or more extrahepatic diseases were present, including type 1 diabetes, vitiligo, glomerulonephritis, autoimmune hemolytic anemia, hypoglycemia with hyperinsulinism, autoimmune thyroiditis, chronic mucocutaneous candidiasis with hypoparathyroidism, and multiple cutaneous and visceral telangiectasias. Treatment with prednisone and azathioprine improved the liver condition in 16 of the 18 patients given treatment. In eight of them discontinuation of treatment resulted in rapid relapse; 14 are still receiving treatment and have stable hepatic function with follow-up from 8 months to 6 1/2 years. Only two are free of treatment. Four children died, two in spite of immunosuppressive therapy, one during a relapse, and one of extrahepatic disease. These results indicate that this autoimmune inflammatory liver disease may have onset early in life, with several clinical patterns; is frequently associated with certain types of extrahepatic manifestations of autoimmune origin; and is a potentially fatal disease for which immunosuppressive treatment must be started early.

Drug-induced hepatitis associated with anticytoplasmic organelle autoantibodies

A study from five hepatology units documenting 157 cases of drug-induced hepatitis and a second study from a laboratory of immunology which tested more than 100,000 sera permitted us to establish the frequency of antiorganelle antibodies and their diagnostic value in drug-induced hepatitis. In drug-induced hepatitis caused by a heterogenous group of drugs consisting of ajmaline, aminopterine, isaxonine, isoniazid, perhexiline, phenylbutazone and troleandromycine, antiorganelle antibodies were absent or rare. In drug-induced hepatitis caused by another heterogenous group of drugs, including clometacin, fenofibrate, oxyphenisatin and papaverine, antismooth muscle, antinucleus and antimitochondria antibodies were found in isolation or in different combinations in 70% of cases. From the presence of antismooth muscle antibodies in sera, we could trace 30 cases of clometacin-induced hepatitis. The third group included drug-induced hepatitis with special antibody:iproniazid-induced hepatitis with antimitochondrial antibody 6 and tienilic acid (ticrynafen)-induced hepatitis with antiliver/kidney microsome antibody 2 (anti-LKM2). These two antibodies are rare in routine sera and were absent in patients who received the drug and had no liver damage. From the presence of corresponding antibodies, we detected six cases of iproniazid-induced hepatitis and 67 cases of tienilic acid-induced hepatitis. Antiorganelle antibodies found in high titers disappeared in 2 to 24 months following withdrawal of the offending drug. The fourth group was represented by halothane-induced hepatitis; antiliver/kidney microsome antibody 1 was weak and infrequent. Similarities between drug-induced hepatitis of the second group and lupoïd hepatitis suggest that drugs may reveal this spontaneous disorder.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-liver-kidney microsome antibody recognizes a 50,000 molecular weight protein of the endoplasmic reticulum

Children with autoimmune chronic active hepatitis may have high titers of antibodies detected by immunofluorescence staining of hepatocytes and tubular cells in rat liver and kidney sections, respectively. These antibodies are directed against antigens contained in microsomal fractions prepared from these two organs. We have found that sera from these patients recognized a 50,000 mol wt protein present in higher concentration in smooth microsome subfractions compared with rough microsome subfractions. This protein is an integral membrane protein and is not glycosylated. It is exposed on the cytoplasmic face of the endoplasmic reticulum and is rather resistant to proteolysis with proteinase K. Since patients with liver disease of different etiology and similar severity of cell lysis do not give rise to liver-kidney microsome antibody (LKMA), lysis of hepatocytes is apparently not a sufficient condition for their development.

[Significance of autoantibodies in the diagnosis of non-A, non-B hepatitis]

Various autoantibodies against different components of the hepatocytes have been demonstrated in chronic active hepatitis (CAH) which is an etiologically heterogeneous disease. These antibodies are essentially antinuclear antibodies (ANA), antibodies against liver cell membranes (LMA), antibodies against a microsomal antigen from liver and kidney (LKM), antibodies against soluble liver antigen (SLA) and antimitochondrial antibodies (AMA). These various autoantibodies mentioned could not be demonstrated in 18 patients with clearly established acute and 27 patients with clearly established acute and 27 patients with clearly established chronic hepatitis non-A-non-B. In addition these autoantibodies could not be found in our own cases of clearly established hepatitis non-A-non-B after the acute stage of the disease. Testing for the presence of these antibodies thus helps essentially to differentiate the autoimmunologically caused form of CAH from the CAH non-A-non-B.

Detection of liver-kidney microsomal autoantibodies by radioimmunoassay and their relation to anti-mitochondrial antibodies in inflammatory liver diseases

A radioimmunoassay (RIA) was developed for the detection of liver-kidney microsomal (LKM) autoantibodies. These were detected in four of 62 patients with HBsAg negative chronic active hepatitis (CAH) and in one patient with mixed connective tissue disease (MCTD). LKM antibodies were not detected in other hepatic and non-hepatic diseases. Other autoantibodies, especially anti-mitochondrial ones, do not react in this assay system. Sera positive for LKM antibodies by RIA showed a cytoplasmic staining of hepatocytes and proximal renal tubules by immunofluorescence. The LKM antigen was detected by RIA in microsomes prepared from rat liver, kidney, stomach, heart, lung, and skeletal muscle. It was destroyed after treatment with trypsin and chymotrypsin, but preserved after treatment with RNAase, DNAase and neuraminidase. Upon centrifugation of purified rat liver microsomes in CsCl gradient, LKM reactivity was detected at a density of 1.20 g/ml. In addition, the M2 antigen of the inner mitochondrial membrane specific for primary biliary cirrhosis (PBC) was localized at 1.28 g/ml in these density gradient fractions. The LKM antigen could not be solubilized. The presence of LKM antibodies characterizes a distinct subgroup of HBsAg negative CAH; they do not occur in PBC.

Correlations between polychlorinated biphenyl immunotoxicity, the aromatic hydrocarbon locus, and liver microsomal enzyme induction in C57BL/6 and DBA/2 mice

The suppression of the antibody response by polychlorinated biphenyls (PCB) in mice is dependent on the planarity of the PCB molecule and on the expression of the aromatic hydrocarbon (Ah) receptor. In this study, the hypothesis that this form of immunotoxicity is a consequence of the activation of the Ah gene complex and that other compounds which are Ah receptor ligands would also be immunotoxic was tested. 2,2',4,4'-Tetrachlorobiphenyl (TCB), 2,3,3',4,4',5-hexachlorobiphenyl (HCB), phenobarbital (PB), or beta-naphthoflavone (BNF) was given ip to either C57BL/6 (B6,Ahb/Ahb) or DBA/2 (D2, Ahd/Ahd) mice 2 days before immunization with sheep erythrocytes. Organ weights, histopathology, hemagglutinating antibody titers, and the splenic direct antibody plaque-forming cell (PFC) response were evaluated on Day 5. Hepatic aryl hydrocarbon hydroxylase (AHH) induction by these compounds and by 2,2',5,5'-TCB and 3,3',4,4'-TCB was measured as an indicator of Ah receptor binding and subsequent activation of the Ah gene complex by methylcholanthrene-type inducers, while aminopyrine N-demethylase (APND) was measured as an indicator of PB-type induction. 2,2',4,4'-TCB and PB had no effects on the immune parameters of either strain but induced APND activity in both strains. 2,2',5,5'-TCB slightly induced APND activity in B6 mice. 2,3,3',4,4',5-HCB caused a 70% suppression of PFC per spleen, decreased the serum antibody titer, elevated cytochrome P-450 levels (193%), induced both APND (165%) and AHH (217%) activity in B6 mice, but it induced only APND (156%) activity in D2 mice. 3,3',4,4'-TCB elevated cytochrome P-450 levels (210%) and induced both APND (129%) and AHH (321%) activities in B6 mice but only increased APND activities (115%) in D2 mice. BNF elevated cytochrome P-450 (144%), caused a 49% suppression in PFC per spleen, and induced both APND (156%) and AHH (248%) activities but only in B6 mice. These results support the hypothesis that the immunotoxicity caused by halogenated and polycyclic aromatic hydrocarbons is a consequence of activation of the Ah gene complex and suggests that this toxic effect can be initiated by any Ah receptor ligand.

Androgen regulation of specific mRNAs, endoplasmic reticulum and Golgi-system

The seminal vesicles of male rat secrete tissue-specific proteins under androgenic control. The effects of testosterone on the rough endoplasmic reticulum (RER) and Golgi-system of this tissue have been quantified using specific antibodies. Castration was followed within 2 weeks by a 10-fold reduction in RER-specific membrane protein. This was reversed by testosterone commencing about 4 h after exposure to the hormone. Five individual major RER antigens were separately quantified; these changed coordinately in response to androgen. No hormone-induced changes were seen in Golgi-specific membrane protein. Hormonal effects on mRNAs for two major secretory proteins were also measured using hybridisation to specific cDNA probes. The cellular concentrations of the two mRNAs changed by at least 1000-fold during hormonal treatment. A detailed examination of the time-course of induction by testosterone failed to show any temporal distinction between effects on mRNA and RER.

A new anti-liver-kidney microsome antibody (anti-LKM2) in tienilic acid-induced hepatitis

The sera of 131 patients with anti-liver-kidney microsome antibodies (anti-LKM) detected between 1973 and 1979 in two different laboratories were re-examined. (1) Eighty-six anti-LKM corresponded to the description given by Rizzetto, Swana & Doniach (1973), with a pattern of fluorescence predominating on the 3rd portion of the proximal tubules (P3). This group comprised 45 cases of idiopathic chronic hepatitis or idiopathic cirrhosis and one case of halothane-induced hepatitis. (2) Forty-five anti-LKM gave a different pattern on male mouse liver and male rat kidney: (a) fluorescence was greater on centrolobular than on periportal hepatocytes; (b) the first and second portions of proximal tubules (P1 and P2) predominated over P3; (c) P1 fluorescence was equally intense as P2 and (d) P3 cells were heterogeneous with one cell out of 20 more positive than the rest. Absorption tests confirmed that the corresponding antigen was also present in the liver microsomal fraction. A retrospective clinical study discovered tienilic acid-induced hepatitis in all cases. We suggest naming this new antibody 'anti-LKM2'.

Liver cell surface expression of the antigen reacting with liver-kidney microsomal antibody (LKM)

To test the hypothesis that liver membrane antibodies, found in all liver-kidney microsomal antibody (LKM) positive sera from patients with chronic active hepatitis, were directed against antigens shared by both hepatocellular endoplasmic reticulum and plasma membranes, absorption experiments have been performed using viable isolated hepatocytes and liver microsomes as antigens. Results are in agreement with the above hypothesis, LKM, which displays a restricted organ specificity, is thus able to react with antigenic determinants expressed on the liver cell surface, as it has been demonstrated for strictly organ specific antibodies directed against thyroid, adrenal and gastric parietal cell microsomes.

Increased incidence of hypothyroidism in primary biliary cirrhosis

We examined the thyroid status of 58 patients with primary biliary cirrhosis (PBC) using total serum thyroxin, thyroid hormone binding ratio, free thyroxin index, serum TSH, antithyroglobulin, and antimicrosomal antibodies. Seven patients were known to be hypothyroid prior to the diagnosis of PBC. Six additional patients were found to have biochemical evidence of hypothyroidism. The prevalence of hypothyroidism was 12% if we include only those six PBC patients with newly diagnosed hypothyroidism or 22% if we include all 13 patients. Five of the 58 patients had evidence for an elevation of thyroid hormone binding capacity. Three hypothyroid patients had normal total thyroxins with low thyroid hormone binding ratios. Two euthyroid patients had elevated total T4s with low thyroid hormone binding ratio and normal FTI. The prevalence of positive antimicrosomal antibodies was 34%, including 11 euthyroid PBC patients. The prevalence of positive antithyroglobulin antibodies was 20% including five euthyroid patients. There was no association between HLA DR3 or DR5 and the patients with hypothyroidism and/or antithyroid antibodies. Because fatigue, lethargy, and anorexia as well as hypercholesterolemia are common features of both hypothyroidism and PBC, patients with PBC should be screened for evidence of thyroid dysfunction. Thyroid disease may precede the diagnosis of PBC by several years. Therefore, the development of cholestatic liver disease in a patient with known autoimmune thyroiditis should arouse suspicion of PBC.