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Ghozzi M, Mankai A, Zneidi I, Manoubi W, Melayah S, Mechi F, Trabelsi A, Ghedira I. Serological markers of rheumatoid arthritis in patients with primary biliary cholangitis and the vice versa: A Tunisian study. Immunobiology 2023; 228:152398. [PMID: 37269587 DOI: 10.1016/j.imbio.2023.152398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/14/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023]
Abstract
BACKGROUND Primary biliary cholangitis (PBC) is an autoimmune disease of the liver characterized by destructive lymphocytic cholangitis and anti-mitochondrial antibodies (AMA). Anti-gp210 and anti-Sp100, are used for the diagnosis of PBC in AMA-negative PBC patients. Patients with PBC have a propensity to have an extrahepatic manifestation which is especially autoimmune. OBJECTIVE We aimed to determine the frequency of serological markers of rheumatoid arthritis (RA) (CCP-Ab or RF) in PBC patients and to do the vice versa. METHODS Our PBC study included 70 patients with PBC and 80 healthy blood donors (HBD) and our RA study included 75 patients with RA and 75 HBD. Anti-cyclic citrullinated peptide antibodies (CCP-Ab) and rheumatoid factor (RF) were performed by indirect ELISA. AMA, anti-Sp100 and anti-gp210 were determined by indirect immunofluorescence. RESULTS RA autoantibodies (CCP-Ab or RF) were more frequent in PBC patients than in HBD (65.7% vs. 8.7% p 〈10-6). CCP-Ab were significantly more frequent in patients than in controls (15.7% vs. 2.5%; p = 0.004). Nine patients had both CCP-Ab and RF vs. none of controls (12.8% vs. 0%; p = 0.001). RF were detected in 45 patients with PBC and in 5 HBD (64.3% vs. 6.2%; p 〈10-6). In PBC patients, RF were more frequent than CCP-Ab (64.3% vs. 15.7%; p 〈10-6). RF-IgG were present in 18.5% of patients; RF-immunoglobulin (Ig) A in 34.3% and RF-IgM in 54.3%. These frequencies were significantly higher than those found in control group (1.2% for RF-IgG (p 〈10-3); 0% for RF-IgA (p 〈10-6); and 6.2% for RF-IgM (p 〈10-6)). In our PBC patients, RF-IgA were more frequent than RF-IgG (34.3% vs. 18.5%; p = 0.03) and than CCP-Ab (34.3% vs. 15.7%; p = 0.01). Six patients had only RF-IgA versus none of the control group (8.6% vs. 0%; p = 0.01). AMA, anti-Sp100 and anti-gp 210 were absent in all RA patients. CONCLUSIONS Serological markers of RA were more frequent in PBC patients than in HBD and the vice versa was not true.
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Affiliation(s)
- Mariam Ghozzi
- Laboratory of Immunology, Farhat Hached University Hospital, Sousse, Tunisia; Faculty of Pharmacy, Department of Immunology, University of Monastir, Monastir, Tunisia; Research Laboratory for "Epidemiology and Immunogenetics of Viral Infections" (LR14SP02), Sahloul University Hospital, University of Sousse, Sousse, Tunisia.
| | - Amani Mankai
- High School of Sciences and Techniques of Health, Tunis El Manar University, Tunis, Tunisia; Research Unit "Obesity: Etiopathology and Treatment, UR18ES01", National Institute of Nutrition and Food Technology, Tunis, Tunisia
| | - Inssaf Zneidi
- Faculty of Pharmacy, Department of Immunology, University of Monastir, Monastir, Tunisia
| | - Wiem Manoubi
- Erasmus University Medical Centre, Department of Neuroscience, Rotterdam, Netherlands
| | - Sarra Melayah
- Laboratory of Immunology, Farhat Hached University Hospital, Sousse, Tunisia; Faculty of Pharmacy, Department of Immunology, University of Monastir, Monastir, Tunisia; LR12SP11, Biochemistry Department, Sahloul University Hospital, Sousse, Tunisia
| | - Fatma Mechi
- Laboratory of Immunology, Farhat Hached University Hospital, Sousse, Tunisia; Faculty of Pharmacy, Department of Immunology, University of Monastir, Monastir, Tunisia
| | - Abdelhalim Trabelsi
- Research Laboratory for "Epidemiology and Immunogenetics of Viral Infections" (LR14SP02), Sahloul University Hospital, University of Sousse, Sousse, Tunisia; Laboratory of Microbiology and Virology, Sahloul University Hospital, Sousse, Tunisia
| | - Ibtissem Ghedira
- Laboratory of Immunology, Farhat Hached University Hospital, Sousse, Tunisia; Faculty of Pharmacy, Department of Immunology, University of Monastir, Monastir, Tunisia
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Khanna A, Leighton J, Lee Wong L, Jones DE. Symptoms of PBC - Pathophysiology and management. Best Pract Res Clin Gastroenterol 2018; 34-35:41-47. [PMID: 30343709 DOI: 10.1016/j.bpg.2018.06.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/08/2018] [Indexed: 01/31/2023]
Abstract
Primary biliary cholangitis is a chronic cholestatic liver disease characterised by progressive bile duct damage and, ultimately, biliary cirrhosis. Though up to fifty percent of the patients can be asymptomatic at presentation, symptoms when present are frequently debilitating with significant impact on quality of life and functional status. Characteristic symptoms include pruritus, fatigue and an increasingly recognised mild cognitive impairment. With the exception of pruritus, the "classic" cholestatic symptom, therapeutic options to treat PBC related symptoms are currently limited leaving patients with often significant residual problems. Symptoms can frequently contribute to depression and social isolation further compounding the quality of life impairment. There is need to better understand the current therapeutic options available in order to optimise their use, and to explore newer avenues to understand the pathophysiology of the symptom-generating processed in PBC in order to develop new therapies.
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Affiliation(s)
- Amardeep Khanna
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK; NIHR Biomedical Research Centre, Newcastle University, Newcastle upon Tyne, UK.
| | - Jess Leighton
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Lin Lee Wong
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK; NIHR Biomedical Research Centre, Newcastle University, Newcastle upon Tyne, UK.
| | - David E Jones
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK; NIHR Biomedical Research Centre, Newcastle University, Newcastle upon Tyne, UK.
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Palioura S, Herkel J, Simonović M, Lohse AW, Söll D. Human SepSecS or SLA/LP: selenocysteine formation and autoimmune hepatitis. Biol Chem 2011; 391:771-6. [PMID: 20623998 DOI: 10.1515/bc.2010.078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Selenocysteine, the 21st genetically encoded amino acid, is the major form of the antioxidant trace element selenium in the human body. In eukaryotes and archaea its synthesis proceeds through a phosphorylated intermediate in a tRNA-dependent fashion. The final step of selenocysteine formation is catalyzed by O-phosphoseryl-tRNA:selenocysteinyl-tRNA synthase (SepSecS) that converts phosphoseryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec). The human SepSecS protein is also known as soluble liver antigen/liver pancreas (SLA/LP), which represents one of the antigens of autoimmune hepatitis. Here we review the discovery of human SepSecS and the current understanding of the immunogenicity of SLA/LP in autoimmune hepatitis.
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Affiliation(s)
- Sotiria Palioura
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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4
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Anti-Saccharomyces cerevisiae antibodies in primary biliary cirrhosis. Dig Dis Sci 2008; 53:1983-7. [PMID: 18049897 DOI: 10.1007/s10620-007-0092-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 10/27/2007] [Indexed: 12/12/2022]
Abstract
AIM The aim of this study was to evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with primary biliary cirrhosis (PBC). METHODS ASCA, IgG, and IgA, were determined by ELISA in sera of 95 PBC patients; 80 healthy blood donors served as controls. RESULTS The frequency of ASCA (IgG or IgA) was significantly higher in PBC patients than in the control group (24.2% vs 3.7%, P = 0.0001). The frequency of ASCA IgG and ASCA IgA in PBC patients was also significantly higher than that found in the control group (18.9% vs 2.5%, P = 0.0006 and 11.6% vs 1.2%, P = 0.007, respectively). Six patients out of 95 (6.3%) had both ASCA IgG and ASCA IgA; in contrast, none of the control group had both isotypes (P = 0.02). There was no correlation between ASCA levels and mitochondrial autoantibodies (AMA) titres in PBC patients. CONCLUSION We conclude that ASCA are common in patients with PBC.
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Abstract
Autoimmune phenomena have been recognized in primary biliary cirrhosis (PBC) for more than 50 years and the specificity of the characteristic responses directed at highly conserved mitochondrial antigens determined in detail over the past 20. Effecter autoreactive immune responses are characterized and potential mechanisms of breakdown of tolerance to self proposed. Elements of the clinical pattern of PBC, including the recurrence of the disease across HLA boundaries after liver transplantation, remain difficult to reconcile with a simple autoimmune model. Alternative (but not necessary mutually exclusive) pathogenetic models have been outlined, including a potential role for retroviral pathogens and directly cytopathic effects.
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Hattori N, Nakayama Y, Kitagawa K, Li T, Inagaki C. Development of anti-PRL (prolactin) autoantibodies by homologous PRL in rats: a model for macroprolactinemia. Endocrinology 2007; 148:2465-70. [PMID: 17303669 DOI: 10.1210/en.2006-1208] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Macroprolactinemia is hyperprolactinemia in humans mainly due to anti-PRL (prolactin) autoantibodies and is a pitfall for the differential diagnosis of hyperprolactinemia. Despite its high prevalence, the pathogenesis remains unclear. In this study, we examined whether anti-PRL autoantibodies develop via immunization with homologous rat pituitary PRL in rats to elucidate what mechanisms are involved and whether they cause hyperprolactinemia with low PRL bioactivity, as seen in human macroprolactinemia. Anti-PRL antibodies were developed in 19 of 20 rats immunized with homologous rat pituitary PRL and 29 of 30 rats with heterogeneous bovine or porcine pituitary PRL but did not develop in 25 control rats. In rats with anti-PRL antibodies, the basal serum PRL levels were elevated, and a provocative test for PRL secretion using dopamine D2 receptor antagonist (metoclopramide) showed a normal rising response with a slower clearance of PRL because of the accumulation of macroprolactin in blood. Antibodies developed by porcine or rat pituitary PRL reduced the bioactivity of rat serum PRL, and gonadal functions in these rats were normal despite hyperprolactinemia. Anti-PRL antibodies were stable and persisted for at least 5 wk after the final injection of PRL. These findings suggest that pituitary PRL, even if homologous, has antigenicity, leading to the development of anti-PRL autoantibodies. We successfully produced an animal model of human macroprolactinemia, with which we can explain the mechanisms of its clinical characteristics, i.e. asymptomatic hyperprolactinemia.
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Affiliation(s)
- Naoki Hattori
- Department of Pharmacology, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi-City, Osaka 570-8506, Japan.
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Miyakawa H, Tanaka A, Selmi C, Hosoya N, Mataki N, Kikuchi K, Kato T, Arai J, Goto T, Gershwin ME. Serum reactivity against bacterial pyruvate dehydrogenase: increasing the specificity of anti-mitochondrial antibodies for the diagnosis of primary biliary cirrhosis. Clin Dev Immunol 2007; 13:289-94. [PMID: 17162370 PMCID: PMC2270775 DOI: 10.1080/17402520600668706] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Antimitochondrial antibodies (AMA) are the serum hallmark of primary biliary cirrhosis (PBC). However, AMA-positivity can be found in non-PBC sera when lower dilutions are used, thus raising issues about the specificity and sensitivity of the test. AMA reacts primarily with the lipoylated domains of pyruvate dehydrogenase-E2 (PDC-E2) which is highly conserved across species, including bacteria. We studied 77 serum samples, including 24 from patients with anti-PDC-E2-positive PBC and 53 controls (16 with autoimmune hepatitis (AIH), 10 with primary sclerosing cholangitis (PSC), and 27 healthy individuals) for their reactivities at serial dilutions (1:10, 1:20 and 1:40) against Escherichia coli DH5 alpha lysate overexpressing human PDC-E2 using immunoblotting (IB). A murine anti-human PDC-E2 monoclonal antibody (mAB) was used as control. We further studied positive sera using adsorption with a synthetic E. coli peptide sharing similarity with human PDC-E2. Finally, we verified whether a unique buffer for E. coli preparation could reduce non-specific serum reactivity. Results demonstrated that 100% of anti-PDC-E2-positive PBC and up to 38% of control sera at 1:10 dilution recognized E. coli PDC-E2 at IB while dilution tests indicated that the overall potency of PBC reactivity was 100-fold higher compared to controls. In fact, a subgroup (20-38%) of non-PBC sera were positive at low titers but lost the reactivity when absorbed with the synthetic E. coli peptide. Finally, our unique buffer reduced the reactivity of non-PBC sera as measured by ELISA. In conclusion, we demonstrated that weak cross-reactivity with E. coli PDC-E2 occurs in non-PBC sera at lower dilutions and that such reactivity is not due to AMA-positivity. The use of a specific buffer might avoid the risk of false positive AMA determinations when E. coli-expressed recombinant antigens are used.
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Affiliation(s)
- Hiroshi Miyakawa
- Fourth Department of Internal Medicine, Teikyo University School of Medicine, Kanagawa 213-8507, Japan
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8
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Abstract
Primary biliary cirrhosis (PBC) is a disease of unknown etiology leading to progressive destruction of small intrahepatic bile ducts and eventually to liver cirrhosis and failure. It is characterised by female predominance and serum auto-antibodies to mitochondrial antigens targeting the E2 components of the 2-oxoacid dehydrogenase complex. Although they are associated with disease pathogenesis, no concrete evidence has been presented so far. Epidemiological data indicate that a geographical clustering of cases and possible environmental factors are implicated in pathogenesis. A number of genetic factors play a role in determining disease susceptibility or progression, although no definitive conclusion has been reached so far. A key factor to immune pathogenesis is considered to be the breakdown of immune tolerance, either through molecular mimicry or through the so called determinant density model. In this review, the available data regarding the pathogenesis of primary biliary cirrhosis are described and discussed. A new unifying hypothesis based on early endothelin overproduction in primary biliary cirrhosis (PBC) is presented and discussed.
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9
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Abstract
Primary biliary cirrhosis (PBC) is characterized by the presence of high-titer disease specific autoantibodies directed against mitochondrial antigens (AMA) of the inner mitochondrial membrane, that are members of the 2-oxo acid complex. Among numerous other autoantibodies found in PBC the focus of ongoing studies is on the PBC-specific anti-nuclear antibodies, that are of diagnostic and clinical relevance since they can be used as a 'positive tool' in the diagnosis of AMA-negative PBC while at the same time identifying a subgroup of patients with more advanced liver disease.
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10
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Botrè F, Botrè C, Podestà E, Podda M, Invernizzi P. Effect of anti-carbonic anhydrase antibodies on carbonic anhydrases I and II. Clin Chem 2003; 49:1221-3. [PMID: 12816932 DOI: 10.1373/49.7.1221] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Francesco Botrè
- Controllo e Gestione delle Merci e del oro Impatto sull'Ambiente Department, La Sapienza University of Rome, Via del Castro Laurenziano 9, 00161 Rome, Italy.
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11
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Palmer JM, Kirby JA, Jones DEJ. The immunology of primary biliary cirrhosis: the end of the beginning? Clin Exp Immunol 2002; 129:191-7. [PMID: 12165073 PMCID: PMC1906441 DOI: 10.1046/j.1365-2249.2002.01948.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2002] [Indexed: 12/30/2022] Open
Abstract
The chronic liver disease primary biliary cirrhosis (PBC) is characterised by autoreactive B-cell and T-cell responses directed against mitochondrial antigens. In recent years these responses have been extensively characterised and the principal PBC associated autoantigen identified as pyruvate dehydrogenase complex (PDC). The identification of anti-PDC responses (present in over 95% of PDC patients) has given rise to important questions pertinent to our understanding of the pathogenesis of PBC. What specific role to anti-PDC responses play in target cell damage? How and why does immune tolerance break down to as highly conserved and ubiquitously expressed self-antigen as PDC? Why does breakdown in tolerance to an antigen present in all nucleated cells result in damage restricted to the intra-hepatic bile ducts? In attempting to answer these key questions we have, in this review, proposed a unifying hypothesis for the pathogenesis of PBC.
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Affiliation(s)
- J M Palmer
- Centre for Liver Research, University of Newcastle, Newcastle-upon-Tyne, UK
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12
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Odin JA, Huebert RC, Casciola-Rosen L, LaRusso NF, Rosen A. Bcl-2–dependent oxidation of pyruvate dehydrogenase-E2, a primary biliary cirrhosis autoantigen, during apoptosis. J Clin Invest 2001. [DOI: 10.1172/jci200110716] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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13
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Kita H, Mackay IR, Van De Water J, Gershwin ME. The lymphoid liver: considerations on pathways to autoimmune injury. Gastroenterology 2001; 120:1485-501. [PMID: 11313320 DOI: 10.1053/gast.2001.22441] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Immunologic injury in the liver involves immigrant T and B lymphocytes and a resident lymphoid population that comprises distinct lymphocytic cells and accessory cells. The forerunner to autoimmunity is breaching of natural self-tolerance and hence the disruption of a fundamental property of the immune system. Such breaching occurs by processes that include inflammatory activation of immunocytes and macrophages, spillage of intracellular constituents, and epitope mimicry by constituents of microorganisms, with these acting on a genetically conditional phenotype; compounding factors include aberrations of apoptosis, whether insufficient or excess. The downstream end requires specifically directed inflammatory leukocyte traffic as an essential component of autoimmune expressions in the liver. The culmination is an orchestrated attack on hepatocytes or biliary epithelial cells by multiple effector pathways. Progress in type 1 autoimmune hepatitis still requires knowledge of a disease-specific autoantigen(s) involved in T-cell reactivity, although such knowledge in type 2 autoimmune hepatitis, in which the known autoantigen is cytochrome P4502D6, has not yet been integrated into a clearly defined scheme of pathogenesis. For PBC there has been a very promising amalgamation of molecular knowledge of the mitochondrial autoantigens. Future insights require deeper analysis of molecular, genetic, macroenvironmental, and microenvironmental elements in predisposition.
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Affiliation(s)
- H Kita
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis School of Medicine, Davis, California 95616, USA
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14
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Abstract
The automimmune liver disease primary biliary cirrhosis (PBC) is characterised by serum autoantibodies directed at mitochondrial and nuclear antigens (seen in most patients and a subset of patients, respectively). The antimitochondrial antibodies (AMA) characteristic of PBC are directed at members of the 2-oxoacid dehydrogenase components of multienzyme complexes; in particular, the E2 and E3 binding protein (E3BP) components of the pyruvate dehydrogenase complex (PDC). The presence of autoantibodies reactive with PDC-E2 and/or E3BP is strongly predictive of the presence of PBC. Therefore, the detection of these antibodies plays a very important role in the diagnosis of PBC. Originally demonstrated using immunofluorescence approaches, AMA can now be detected by the use of commercially available enzyme linked immunosorbent assays (ELISAs). Although the ELISA based approaches have advantages in terms of laboratory practicality, they are slightly less sensitive for the diagnosis of PBC than immunofluorescence (occasional patients with PBC show reactivity with PDC related antigens not present in the antigen preparations available for use with ELISA). Therefore, immunofluorescence should continue to be available as a complementary diagnostic test for use in occasional patients. In a subset of patients with PBC, autoantibodies are directed at increasingly well characterised nuclear antigens. Antinuclear antibody (ANA) positive patients are typically AMA negative. There are no significant differences in disease phenotype between AMA positive and AMA negative groups. At present, the clinical detection of ANA is mostly by Hep2 immunofluorescence, although ELISA kits for individual nuclear antigens are increasingly becoming available.
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Affiliation(s)
- D E Jones
- Centre for Liver Research, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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15
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Abstract
The history of primary biliary cirrhosis (PBC) began in 1851, with autoimmunity introduced in 1958 and expanded from the 1960s on. In PBC, autoantibodies are present to mitochondria-located antigens (AMA) and to nuclear-located antigens (ANA). The AMA react with E2 subunits of three members of the 2-oxoacid dehydrogenase complex family, but most frequently with pyruvate dehydrogenase complex (PDC); the inner lipoyl domain of PDC-E2 contains a major B- and T-cell epitope. The ANA react with three nuclear components, centromeric proteins, nuclear dot proteins and nuclear pore complex. Autoimmune diseases including PBC reflect a failure in mechanisms of self-tolerance which is developed in central lymphoid tissues in embryonic life by deletion of self-reactive lymphocytes, and maintained in peripheral tissues in post-natal life by regulatory processes. Primary biliary cirrhosis has not yet been identified with failure in any one particular tolerance mechanism. Genetic influences are revealed by familial occurrences and by associations with HLA alleles, and environmental influences by epidemiological data. A lead to pathogenesis is the accumulation uniquely in PBC of PDC-E2-like material at the plasma membrance of biliary epithelial cells (BECs). Although the origin of this accumulation of PDC-E2 at the surface of BECs is uncertain, it provides a credible 'tissue-specific' target for an autoimmune attack by T and B lymphocytes at the site of the actual pathology.
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Affiliation(s)
- I R Mackay
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, 3800, Australia
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16
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Jones DE, Palmer JM, Yeaman SJ, Kirby JA, Bassendine MF. Breakdown of tolerance to pyruvate dehydrogenase complex in experimental autoimmune cholangitis: a mouse model of primary biliary cirrhosis. Hepatology 1999; 30:65-70. [PMID: 10385640 DOI: 10.1002/hep.510300123] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
The autoimmune liver disease primary biliary cirrhosis (PBC) is characterized by autoreactive responses to a highly conserved self-antigen, pyruvate dehydrogenase complex (PDC). We recently reported the development of PBC-like lesions in SJL mice sensitized with PDC and have named this model disease experimental autoimmune cholangitis (EAC). In the present study, the breakdown of tolerance to PDC has been investigated in animals sensitized for EAC. Splenic mononuclear cells from SJL mice sensitized with bovine heart PDC (bPDC) in adjuvant showed T-cell proliferative and mixed Th1/Th2 cytokine secretory responses following in vitro stimulation with bPDC. Despite the likelihood of extensive sequence homology with mouse PDC (there is a greater than 95% sequence identity between rat and human PDC-E2 subunits), bPDC was highly immunogenic inducing significant T- and B-cell responses in the absence of any form of adjuvant. The multi-subunit quaternary structure of intact PDC was critical for this immunostimulatory activity because no response was produced by sensitization with monomeric recombinant PDC-E2 inner lipoyl domain. Mice sensitized with bPDC and CFA developed, within 2 weeks of sensitization, high-titer antibody responses reactive with bPDC that were fully cross-reactive with the murine homologue. Breakdown of T-cell tolerance to self-PDC took significantly longer, not being seen until 20 weeks postsensitization; a similar length of time to that previously shown to be required for EAC lesion development. Conclusions drawn from these data may have important implications for our understanding, and therapeutic manipulation, of PBC in humans.
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Affiliation(s)
- D E Jones
- Centre for Liver Research, University of Newcastle, Framlington Place, Newcastle-upon-Tyne, UK.
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Kuroda M, Morito T, Takagi T, Ohira H, Kokubun M, Kojima T, Ono K, Kochi H, Kasukawa R. Antibodies to E1 and E2/Protein X components of pyruvate dehydrogenase complex in sera of patients with primary biliary cirrhosis. J Hepatol 1996; 25:867-76. [PMID: 9007715 DOI: 10.1016/s0168-8278(96)80291-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AIMS/METHODS Using purified E1 component of pyruvate dehydrogenase complex (PDC) from bovine heart, we measured the levels of anti-E1 antibodies in PBC sera using ELISA and determined the degree of inhibition that these antibodies exerted on E1 enzyme activity. We also estimated levels of anti-E2/Protein X (Pro-X) antibodies in PBC sera using purified E2 and Pro-X of PDC which were copurified with E1. RESULTS/CONCLUSIONS Anti-E1 antibodies were detected in 87.5% (35/40) of PBC sera. Some of these sera inhibited E1 enzyme activity but inhibition did not correlate with levels of anti-E1 antibodies. A high positive correlation (r = 0.918) was found between levels of anti-E1 and anti-E2/Pro-X antibodies, suggesting that anti-PDC antibody production was stimulated by PDC itself. Levels of IgG class anti-E2/Pro-X antibodies were significantly higher in sera of symptomatic PBC patients than in those of asymptomatic PBC patients. It was also found that patients who were positive for only IgM class anti-E2/Pro-X antibodies had early-stage PBC.
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Affiliation(s)
- M Kuroda
- Department of Internal Medicine II, Fukushima Medical College, Japan
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18
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Galperin C, Gershwin ME. Immunopathology of primary biliary cirrhosis. BAILLIERE'S CLINICAL GASTROENTEROLOGY 1996; 10:461-81. [PMID: 8905119 DOI: 10.1016/s0950-3528(96)90053-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Our understanding of the immunopathology of PBC has dramatically changed with the application of molecular biology techniques in clinical medicine. This has allowed, not only the possibility of characterizing mitochondrial autoantigens fully at the molecular level, but also the identification of specific sites on these molecules that are targetted by autoreactive B and T cells. In addition, the expression of cloned antigens has facilitated the development of the most reliable assays currently available for the detection of mitochondrial autoantibodies. The assessment of the pathogenic capacity of autoreactive T cells, as well as the characterization the PDC-E2 'look alike' molecule expressed on the cell membrane of PBC biliary epithelial cells, remain the major unsolved issues in this disease. Ideally, the continuous effort from both basic and clinical scientist in understanding the pathogenic mechanisms of PBC will lead to more specific, effective, and safer modalities of treatment.
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Affiliation(s)
- C Galperin
- Division of Rheumatology, Allergy and Clinical Immunology, University of California Davis School of Medicine 95616, USA
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Berg PA, Klein R. Mitochondrial antigen/antibody systems in primary biliary cirrhosis: revisited. LIVER 1995; 15:281-92. [PMID: 8609807 DOI: 10.1111/j.1600-0676.1995.tb00687.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Methods for the evaluation of the four antimitochondrial antibody subtypes in primary biliary cirrhosis - anti-M2, -M4, -M8, -M9 - are described. The importance of the application of different preparations for the demonstration of complement fixing antibodies and the detection of antibodies by ELISA or Western blotting is emphasized. Complement fixing antigens can be prepared by discontinuous isopynic sucrose density gradient centrifugation using mitochondrial subfractions derived with from beef heart (M2), rat liver (M4), or pig kidney (M8). Anti-M9 antibodies do not fix complement. For ELISA, the pyruvate dehydrogenase or the ATPase-associated antigen fraction (M2), the sulfite oxidase fraction (M4), and the chromatographically purified M8-fraction should be used. The same antigen fractions are suitable for Western blotting, but anti-M4 and anti-M8 by ELISA and Western blotting a purified fraction prepared from rat liver has to be applied. Correlating antimitochondrial antibody-subtypes with clinical condition and the natural course, there is convincing evidence that especially the presence of complement fixing antibodies against the subtypes M2, M4, and M8 is a reliable indicator for a more active course. Patients expressing only anti-M9 (without anti-M2) have biochemically all the typical features also found in classical anti-M2 positive primary biliary cirrhosis patients, but seem not to advance to late stages. Since these antimitochondrial antibody-subtypes are present even in very early stages stages without changing their pattern during the course, antimitochondrial antibody-profiles can also be taken as early prognostic parameters. The evaluation of the immunological activity by antimitochondrial antibody-subtype testing may further facilitate the decision whether therapy with ursodeoxycholic acid should be combined with steroids and/or immunosuppressive agents. The role of mitochondrial autoantigens in the induction of this chronic destructive bile duct process is also discussed. The concept is put forward that not bile ducts but naive(?) B-cells expose the different mitochondrial antigens, thereby stimulating autoreactive T-cells to provide a second signal for antibody production. The degree of breakage of tolerance to the different mitochondrial epitopes may be one crucial factor which determines the diversity of antimitochondrial antibody-subtypes in patients with primary biliary cirrhosis.
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Affiliation(s)
- P A Berg
- Department of Internal Medicine, University of Tübingen, Germany
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