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An innovative method to identify autoantigens expressed on the endothelial cell surface: serological identification system for autoantigens using a retroviral vector and flow cytometry (SARF). Clin Dev Immunol 2013; 2013:453058. [PMID: 23401699 PMCID: PMC3562638 DOI: 10.1155/2013/453058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 01/23/2023]
Abstract
Autoantibodies against integral membrane proteins are usually pathogenic. Although anti-endothelial cell antibodies (AECAs) are considered to be critical, especially for vascular lesions in collagen diseases, most molecules identified as autoantigens for AECAs are localized within the cell and not expressed on the cell surface. For identification of autoantigens, proteomics and expression library analyses have been performed for many years with some success. To specifically target cell-surface molecules in identification of autoantigens, we constructed a serological identification system for autoantigens using a retroviral vector and flow cytometry (SARF). Here, we present an overview of recent research in AECAs and their target molecules and discuss the principle and the application of SARF. Using SARF, we successfully identified three different membrane proteins: fibronectin leucine-rich transmembrane protein 2 (FLRT2) from patients with systemic lupus erythematosus (SLE), intercellular adhesion molecule 1 (ICAM-1) from a patient with rheumatoid arthritis, and Pk (Gb3/CD77) from an SLE patient with hemolytic anemia, as targets for AECAs. SARF is useful for specific identification of autoantigens expressed on the cell surface, and identification of such interactions of the cell-surface autoantigens and pathogenic autoantibodies may enable the development of more specific intervention strategies in autoimmune diseases.
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Krones E, Graziadei I, Trauner M, Fickert P. Evolving concepts in primary sclerosing cholangitis. Liver Int 2012; 32:352-69. [PMID: 22097926 DOI: 10.1111/j.1478-3231.2011.02607.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/27/2011] [Indexed: 02/13/2023]
Abstract
Patients suffering from primary sclerosing cholangitis (PSC) show considerable differences regarding clinical manifestations (i.e. large duct versus small-duct PSC, presence or absence of concomitant inflammatory bowel disease), disease progression, risk for malignancy and response to therapy, raising the question whether PSC may represent a mixed bag of diseases of different aetiologies. The growing list of secondary causes and diseases 'mimicking' or even overlapping with PSC (e.g. IgG4-associated sclerosing cholangitis), which frequently causes problems in clear-cut discrimination from classic PSC and the emerging knowledge about potential disease modifier genes (e.g. variants of CFTR, TGR5 and MDR3) support such a conceptual view. In addition, PSC in children differs significantly from PSC in adults in several aspects resulting in distinct therapeutic concepts. From a clinical perspective, appropriate categorization and careful differential diagnosis are essential for the management of concerned patients. Therefore, the aim of the current review is to summarize current and evolving pathophysiological concepts and to provide up-to-date perspectives including future treatment strategies for PSC.
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Affiliation(s)
- Elisabeth Krones
- Department of Internal Medicine, Medical University of Graz, Graz, Austria
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Abstract
The aetiology of primary sclerosing cholangitis (PSC) is not known and controversy exists as to whether PSC should be denominated an autoimmune disease. A large number of autoantibodies have been detected in PSC patients, but the specificity of these antibodies is generally low, and the frequencies vary largely between different studies. The presence of autoantibodies in PSC may be the result of a nonspecific dysregulation of the immune system, but the literature in PSC points to the possible presence of specific antibody targets in the biliary epithelium and in neutrophil granulocytes. The present review aims to give an overview of the studies of autoantibodies in PSC, with a particular emphasis on the prevalence, clinical relevance and possible pathogenetic importance of each individual marker.
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Terjung B, Spengler U. Role of auto-antibodies for the diagnosis of chronic cholestatic liver diseases. Clin Rev Allergy Immunol 2006; 28:115-33. [PMID: 15879618 DOI: 10.1385/criai:28:2:115] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Auto-antibodies are an integral part of the diagnostic armentarium in chronic cholestatic liver disorders, such as primary sclerosing cholangitis (PSC), primary biliary cirrhosis (PBC),auto-immune cholangitis, or overlap syndromes among these disorders. However, care should be taken not to overestimate the diagnostic specificity. Auto-antibodies to mitochondrial antigens(AMAs) with reactivity to the E2 subunit of the pyruvate dehydrogenase complex represent the hallmark antibody for the diagnosis of PBC, whereas antinuclear antibodies (ANAs)with low disease specificity are found in up to 50% of these sera. Antibodies that recognize nuclear envelope proteins exert a similarly high diagnostic specificity as AMA in PBC but occur at a rather low prevalence. The role of auto-antibodies is less well-studied for patients with PSC, but there is growing evidence that only antineutrophil cytoplasmic antibodies(ANCAs) are of relevant diagnostic significance. In contrast, auto-antibodies-particularlyAMAs-do not contribute to the diagnosis of auto-immune cholangitis, whereas ANCAs,ANAs, smooth muscle antibodies, and AMAs are of varying significance in PBC-auto-immune hepatitis (AIH) or PSC-AIH overlap syndromes. It has been widely accepted that the course of the auto-antibody serum end point titers are not suited for the clinical management of patients with chronic cholestatic liver disorders. Additionally, auto-antibodies in these disorders usually do not contribute to the immunopathogenesis of the disease.
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MESH Headings
- Antigens, Bacterial/immunology
- Antigens, Nuclear/immunology
- Autoantibodies/blood
- Autoantibodies/immunology
- Autoantigens/immunology
- Autoimmune Diseases/diagnosis
- Autoimmune Diseases/immunology
- Cholangitis, Sclerosing/diagnosis
- Cholangitis, Sclerosing/immunology
- Hepatitis, Autoimmune/diagnosis
- Hepatitis, Autoimmune/immunology
- Humans
- Liver Cirrhosis, Biliary/diagnosis
- Liver Cirrhosis, Biliary/immunology
- Mitochondria, Liver/immunology
- Muscle, Smooth/immunology
- Transglutaminases/immunology
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Affiliation(s)
- Birgit Terjung
- Department of Internal Medicine I, University of Bonn, Bonn, Germany.
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Worthington J, Cullen S, Chapman R. Immunopathogenesis of primary sclerosing cholangitis. Clin Rev Allergy Immunol 2006. [PMID: 15879616 DOI: 10.1385/criai: 28: 2: 093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown etiology;however, lymphocytic portal tract infiltration is suggestive of an immune-mediated basis for PSC. Associations with inflammatory bowel disease--especially ulcerative colitis--and with other auto-immune diseases, together with genetic associations, further suggest that PSC may be an immune-mediated disease. The immunogenetics of PSC have been the subject of active research, and several human leukocyte antigen (HLA)- and non-HLA-associated genes have been implicated in the development of the disease. Lymphocytes derived from the inflamed gut may enter the liver via the enterohepatic circulation to cause hepatic disease.PSC may be triggered in genetically susceptible individuals by infections or toxins entering the portal circulation through a permeable colon and, therefore, evoking an abnormal immune response.
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Affiliation(s)
- Joy Worthington
- Department of Gastroenterology, John Radcliffe Hospital, Headington, Oxford, UK
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Fontana V, Ahn YS, Horstman LH, Tzakis AG, O'Brien CB. Primary sclerosing cholangitis complicating plasma cell dyscrasia (PCD): remission of PCD following liver transplant. Eur J Haematol 2006; 76:167-70. [PMID: 16405440 DOI: 10.1111/j.0902-4441.2005.00589.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the first case of primary sclerosing cholangitis (PSC) complicated with plasma cell dyscrasia (PCD) in which liver transplant resulted in unexpected therapeutic benefit of PCD. A 61-year-old man with 12 yr history of PSC presented with a monoclonal gammopathy of undetermined significance (MGUS) with an IgG level of 3400 mg/dL. It was stable initially for 3 yr but progressed to features consistent with multiple myeloma (MM): IgG rose to 5290 mg/dL along with development of terminal stage of liver failure. Liver transplant was performed in desperation. Unexpectedly, MM underwent clinical remission following transplant. At 3 and 14 months following transplant, IgG stayed below 2080 mg/dL and he was able to return to full-time employment. This case may suggest that chronic antigenic stimulation from cirrhotic liver contributed to MGUS and subsequent transformation to MM. Liver transplant eliminated chronic antigenic stimulation, apparently leading to remission of MM. Since PCD is often associated with other chronic liver diseases, similar benefit may accrue to a range of patients with chronic liver diseases complicating PCD.
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Affiliation(s)
- Vincenzo Fontana
- Division of Hematology/Oncology, University of Miami School of Medicine, Miami, FL 33136, USA
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Abstract
Primary sclerosing cholangitis (PSC) is a fibrosing disease of the intra- and extra-hepatic bile ducts, and is closely associated with inflammatory bowel disease. It is immune mediated, rather than being a classical autoimmune disease. A range of immune abnormalities have been demonstrated in PSC, in particular the findings of a range of autoantibodies, a portal tract infiltrate of functional T cells, a restricted T-cell receptor repertoire, and aberrant expression of HLA molecules on biliary epithelial cells. The immunogenetics of PSC is currently under study and to date 4 key HLA haplotypes associated with PSC have been developed. The trigger factor for the initiation of the immune response may be the ingress of bacteria or other toxic metabolites into the portal circulation through a diseased and permeable bowel wall.
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Affiliation(s)
- Sue Cullen
- Department of Gastroenterology, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
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Abstract
Anti-neutrophil specific antibodies are detected in up to 88% of patients with PSC. The labelling pattern of neutrophils produced by these antibodies when examined by indirect immunofluorescence microscopy is distinct from that produced by anti-neutrophil cytoplasmic antibodies (ANCA) in vasculitic diseases. The antigen(s) recognized by anti-neutrophil antibodies in PSC is not yet known but appears to be localized to the periphery of the nucleus. Accordingly, the term peripheral anti-neutrophil nuclear antibodies (p-ANNA) is more appropriate than the frequently used p-ANCA. As the titre of p-ANNA in PSC does not correlate with disease-specific clinical parameters, they are not useful markers for the management of patients. However, the high prevalence of p-ANNA in PSC makes them a reasonable diagnostic marker if used in conjunction with other standard diagnostic tests. The role of anti-neutrophil antibodies in the pathogenesis of PSC, if any, remains to be established.
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Affiliation(s)
- B Terjung
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, P&S10-518, New York, NY 10032, USA
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Kaya M, Angulo P, Lindor KD. Overlap of autoimmune hepatitis and primary sclerosing cholangitis: an evaluation of a modified scoring system. J Hepatol 2000. [PMID: 11059857 DOI: 10.1016/s0168-8278(00)80004-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIM Recently, the scoring system for the diagnosis of autoimmune hepatitis (AIH) was modified by the International AIH Group. Our aim was to determine the prevalence of AIH in patients with cholangiographically proven primary sclerosing cholangitis (PSC) using this new scoring system. METHODS A total of 211 PSC patients were evaluated. RESULTS Three (1.4%) patients scored more than 15 points ('definite' AIH); 13 (6%) patients scored between 10 and 15 points ('probable' AIH); the remaining 195 (93%) patients had less than 10 points, allowing the exclusion of AIH. The separation of patients with PSC plus AIH from patients with PSC alone was based mostly on serum levels of total globulins (p=0.01), IgG (p=0.001), titers of autoantibodies (p<0.001) and histologic score (p<0.001). Using the older scoring system, four (2%) patients met the criteria for the diagnosis of PSC plus 'definite' AIH and 40 (19%) the diagnosis of PSC plus 'probable' AIH. CONCLUSIONS Overlap of PSC and AIH occurs rarely. The new scoring system seems to more precisely define the potential overlap syndrome between PSC and AIH, although further modification of the new scoring system may provide even better discrimination among these conditions.
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Affiliation(s)
- M Kaya
- Division of Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Tjandra K, Sharkey KA, Swain MG. Progressive development of a Th1-type hepatic cytokine profile in rats with experimental cholangitis. Hepatology 2000; 31:280-90. [PMID: 10655247 DOI: 10.1002/hep.510310204] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are presumed autoimmune chronic cholestatic liver diseases characterized by cholangitis and progressive loss of bile ducts. Cytokines have been postulated to be involved in the progression of these diseases, but their role is poorly defined. Our objectives were to characterize a rat model of cholangitis and to determine Type 1/Type 2 (Th1/Th2) cytokine profile shifts in this model. Cholangitis was induced in Sprague-Dawley rats (200 to 225 g) by low-dose oral administration of the biliary toxin alpha-naphthylisothiocyanate (ANIT) (1 g/kg powdered rat chow ad libitum) for 4, 7, and 14 days. Cholestasis was observed in ANIT-treated animals. Liver histology of ANIT-treated rats showed hepatic inflammation centered on damaged bile ducts, significant bile duct proliferation, and progressive fibrosis. Immunohistochemistry showed enhanced staining of hepatic major histocompatibility complex (MHC) II, CD4, and CD8 in portal areas of ANIT-treated animals. In addition, the hepatic cytokine profile became increasingly Th1 in nature with progressive ANIT treatment. In summary, experimental cholangitis biochemically and histologically mimics human chronic cholangitis and furthermore, is associated with a progressive shift to a more Th1-dominant hepatic cytokine profile. Therefore, this model may be useful for examining the role of cytokines in the progression of chronic cholangitic diseases.
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Affiliation(s)
- K Tjandra
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
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Angulo P, Peter JB, Gershwin ME, DeSotel CK, Shoenfeld Y, Ahmed AE, Lindor KD. Serum autoantibodies in patients with primary sclerosing cholangitis. J Hepatol 2000; 32:182-7. [PMID: 10707856 DOI: 10.1016/s0168-8278(00)80061-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIM Primary sclerosing cholangitis is a chronic cholestatic syndrome with a presumed autoimmune basis frequently associated with inflammatory bowel disease. The aim of this study was to determine the profile and significance of serum autoantibodies in patients with primary sclerosing cholangitis. METHODS Serum samples taken from 73 untreated patients (32 female and 41 male, median age 45 years) with well-defined primary sclerosing cholangitis, and from 75 healthy age- and sex-matched controls were assayed for 20 different autoantibodies. RESULTS Of 73 patients, 71 (97%) were positive for at least 1 autoantibody; whereas 59/73 patients (81%) were positive for > or =3 antibodies. Patients with primary sclerosing cholangitis had a significantly greater rate of positivity than controls for antinuclear, anticardiolipin, antineutrophil cytoplasmic, and antithyroperoxidase antibodies as well as rheumatoid factor. The rate of positivity and serum levels of any of these 20 autoantibodies were not significantly different between patients with primary sclerosing cholangitis and inflammatory bowel disease and those without inflammatory bowel disease. Anticardiolipins were the single group of antibodies that had a significant correlation with the Mayo risk score (r=0.49, p<0.001) and histologic stage of disease (r=0.30, p<0.01). CONCLUSIONS Primary sclerosing cholangitis is associated with a high proportion of non-organ specific autoantibodies. Anticardiolipin antibodies appear to be related to the severity of primary sclerosing cholangitis and may be a useful prognostic marker.
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Affiliation(s)
- P Angulo
- Division of Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Nishioka M, Morshed SA. Heterogeneity of anti-nuclear antibodies in autoimmune liver diseases. Biomed Pharmacother 1999; 53:293-300. [PMID: 10472426 DOI: 10.1016/s0753-3322(00)88498-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- M Nishioka
- Third Department of Internal Medicine, Kagawa Medical University, Kagawa-ken, Japan
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Jeyarajah DR, Netto GJ, Lee SP, Testa G, Abbasoglu O, Husberg BS, Levy MF, Goldstein RM, Gonwa TA, Tillery GW, Crippin JS, Klintmalm GB. Recurrent primary sclerosing cholangitis after orthotopic liver transplantation: is chronic rejection part of the disease process? Transplantation 1998; 66:1300-6. [PMID: 9846512 DOI: 10.1097/00007890-199811270-00006] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND The possibility of primary sclerosing cholangitis (PSC) recurrence after liver transplantation has been debated. The aim of this study is to examine whether recurrent PSC and chronic rejection (CR) are different expressions of the same disease process. METHODS One hundred consecutive patients receiving 118 grafts for the diagnosis of PSC were reviewed and placed into three groups: group A, recurrent disease, as evidenced by cholangiographic and pathologic findings with radiographic arterial flow to the liver (n=18; 15.7%); group B, those who developed CR (n=15; 13.0%); and group C, all others (n=82; 71.3%). Cholangiograms and histopathologic specimens were examined in a blinded fashion. RESULTS Demographic factors were similar, except for age, with a significantly younger age and more episodes of rejection in groups A and B (P<0.03). Group A had a higher incidence of cytomegalovirus hepatitis (P=0.008). Five-year graft survivals for A, B, and C were 64.6%, 33.3%, and 76.1%, respectively (P=0.0001), 5-year patient survivals were 76.2%, 66.7%, and 89.1%, respectively (P=0.0001), and repeat transplantation rates were 27.8%, 46.7%, and 8.5%, respectively (P=0.005). Radiographically, 90% of cholangiograms in patients with recurrent disease showed at least multiple intrahepatic strictures. Histopathologically, patients with recurrent disease and CR shared many features. CONCLUSIONS We have described a high incidence of recurrent PSC and CR in patients who received transplants for PSC. Histopathologic analysis suggests that CR and recurrent PSC could represent a spectrum of indistinguishable disease. However, the distinct difference in clinical outcome, as evidenced by an increased repeat transplantation rate and lower graft and patient survival in the CR group, clearly suggests that they are two distinct entities that require very different treatment strategies.
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Affiliation(s)
- D R Jeyarajah
- Department of Transplantation Surgery, Baylor University Medical Center, Dallas, Texas 75246, USA
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Roozendaal C, Van Milligen de Wit AW, Haagsma EB, Horst G, Schwarze C, Peter HH, Kleibeuker JH, Tervaert JW, Limburg PC, Kallenberg CG. Antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: defined specificities may be associated with distinct clinical features. Am J Med 1998; 105:393-9. [PMID: 9831423 DOI: 10.1016/s0002-9343(98)00294-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE The clinical significance of antineutrophil cytoplasmic autoantibodies (ANCA) in primary sclerosing cholangitis has not been established. We investigated whether analysis of the antigenic specificities of ANCA is useful for delineating clinical subsets of the disease. METHODS Sixty-nine patients with primary sclerosing cholangitis were studied. The presence of ANCA was analyzed by indirect immunofluorescence. Antibodies directed against specific antigens--proteinase 3, myeloperoxidase, elastase, bactericidal/permeability-increasing protein, cathepsin G, and lactoferrin--were identified by enzyme-linked immunosorbent assay. RESULTS ANCA were detected by indirect immunofluorescence in 46 (67%) patients. In antigen-specific enzyme-linked immunosorbent assays, 37 (55%) of the 69 patients had antibodies to one or more antigens: 32 (46%) had antibodies to bactericidal/permeability-increasing protein, 16 (23%) had antibodies to cathepsin G, and 15 (22%) had antibodies to lactoferrin. Only 3 patients had antibodies to proteinase 3. Antibodies to myeloperoxidase or elastase were not detected. Twenty (29%) patients had antibodies to different antigens simultaneously. ANCA as detected by indirect immunofluorescence were not significantly associated with the presence of cirrhosis nor with the coexistence of inflammatory bowel disease. However, antibodies to bactericidal/permeability-increasing protein and cathepsin G were both associated with the presence of cirrhosis, and antibodies to lactoferrin were more frequently detected in patients with primary sclerosing cholangitis in conjunction with ulcerative colitis than in those without inflammatory bowel disease. CONCLUSION Defined specificities of ANCA in primary sclerosing cholangitis may be related to particular clinical features of the disease.
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Affiliation(s)
- C Roozendaal
- Department of Clinical Immunology, University Hospital Groningen, The Netherlands
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Affiliation(s)
- G S Hoffman
- Cleveland Clinic Foundation, Ohio 44195, USA
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Orth T, Kellner R, Diekmann O, Faust J, Meyer zum Büschenfelde KH, Mayet WJ. Identification and characterization of autoantibodies against catalase and alpha-enolase in patients with primary sclerosing cholangitis. Clin Exp Immunol 1998; 112:507-15. [PMID: 9649223 PMCID: PMC1904984 DOI: 10.1046/j.1365-2249.1998.00583.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology. Recent studies have shown that genetic factors and both cellular and humoral immunological abnormalities are important in the pathogenesis of PSC. The most prominent autoantibodies in PSC are anti-neutrophil cytoplasmic antibodies (ANCA). The autoepitopes of ANCA in PSC are not well defined. The aim of this study was to identify corresponding ANCA autoantigens in patients with PSC. A biochemical approach with enrichment and partial purification of soluble neutrophil proteins, detection of autoantibodies by Western blot and partial amino acid sequencing were used. Two new autoantigen/autoantibody systems in patients with PSC were detected: catalase and alpha-enolase. The presence of catalase autoantibodies in 9/15 (60%) and alpha-enolase autoantibodies in 4/15 (27%) was confirmed by ELISA and Western blot. Furthermore, we showed immunoreactions of PSC sera with human biliary epithelial cells, showed the reduction of fluorescence in anti-catalase absorption experiments and observed partial co-localization of anti-catalase antibodies and PSC sera in double-staining experiments on biliary epithelial cells. The anti-catalase antibody-positive PSC patients had a more severe course of disease with a significantly higher alkaline phosphatase compared with the anti-catalase-negative PSC patients (P < 0.06). All ulcerative colitis control sera were anti-catalase antibody-negative. The identified antigens catalase and alpha-enolase can partly explain the ANCA fluorescence on ethanol-fixed and formaldehyde-fixed granulocytes in patients with PSC. Catalase is an important anti-oxidant enzyme and prevents cell damage from highly reactive oxygen-derived free radicals. Catalase autoantibodies might play a pathogenic role in patients with PSC. Our findings support the hypothesis that oxidative stress is one of the pathogenic mechanisms in patients with PSC.
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Affiliation(s)
- T Orth
- I. Medizinische Klinik, Johannes Gutenberg University, Mainz, Germany
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