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Klepper A, Kung A, Vazquez SE, Mitchell A, Mann S, Zorn K, Avila-Vargas I, Kari S, Tekeste M, Castro J, Lee B, Duarte M, Khalili M, Yang M, Wolters P, Price J, Perito E, Feng S, Maher JJ, Lai J, Weiler-Normann C, Lohse AW, DeRisi J, Tana M. Novel autoantibody targets identified in patients with autoimmune hepatitis (AIH) by PhIP-Seq reveals pathogenic insights. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.06.12.23291297. [PMID: 37398174 PMCID: PMC10312872 DOI: 10.1101/2023.06.12.23291297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Autoimmune hepatitis (AIH) is a severe autoimmune disease, characterized by the presence of autoantibodies. However, the role of autoantibodies in the pathophysiology of AIH remains uncertain. Here, we employed Phage Immunoprecipitation-Sequencing (PhIP-Seq) to identify novel autoantibodies in AIH. Using these results, a logistic regression classifier was able to predict which patients had AIH, indicating the presence of a distinct humoral immune signature. To further investigate the autoantibodies most specific to AIH, significant peptides were identified relative to a broad array of controls (298 patients with non-alcoholic fatty liver disease (NAFLD), primary biliary cholangitis (PBC), or healthy controls). Top ranked autoreactive targets included SLA, the target of a well-recognized autoantibody in AIH, and disco interacting protein 2 homolog A (DIP2A). The autoreactive fragment of DIP2A shares a 9-amino acid stretch nearly identical to the U27 protein of HHV-6B, a virus found in the liver. In addition, antibodies against peptides derived from the leucine rich repeat N-terminal (LRRNT) domain of the relaxin family peptide receptor 1 (RXFP1) were highly enriched and specific to AIH. The enriched peptides map to a motif adjacent to the receptor binding domain, which is required for RXFP1 signaling. RXFP1 is a G protein-coupled receptor that binds relaxin-2, an anti-fibrogenic molecule shown to reduce the myofibroblastic phenotype of hepatic stellate cells. Eight of nine patients with antibodies to RXFP1 had evidence of advanced fibrosis (F3 or greater). Furthermore, serum from AIH patients positive for anti-RFXP1 antibody was able to significantly inhibit relaxin-2 signaling in the human monocytic cell line, THP1. Depletion of IgG from anti-RXFP1 positive serum abrogated this effect. These data provide supporting evidence that HHV6 plays a role in the development of AIH and point to a potential pathogenic role for anti-RXFP1 IgG in some patients. Identification of anti-RXFP1 in patient serum may enable risk stratification of AIH patients for fibrosis progression and lead to the development of novel strategies for disease intervention.
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Affiliation(s)
| | - Andrew Kung
- University of California, San Francisco, USA
- Chan Zuckerberg Biohub; San Francisco, CA, USA
| | - Sara E Vazquez
- University of California, San Francisco, USA
- Chan Zuckerberg Biohub; San Francisco, CA, USA
| | - Anthea Mitchell
- University of California, San Francisco, USA
- Chan Zuckerberg Biohub; San Francisco, CA, USA
| | - Sabrina Mann
- University of California, San Francisco, USA
- Chan Zuckerberg Biohub; San Francisco, CA, USA
| | - Kelsey Zorn
- University of California, San Francisco, USA
| | | | - Swathi Kari
- University of California, San Francisco, USA
| | | | | | - Briton Lee
- University of California, San Francisco, USA
| | | | - Mandana Khalili
- University of California, San Francisco, USA
- UCSF Liver Center
| | - Monica Yang
- University of California, San Francisco, USA
| | | | - Jennifer Price
- University of California, San Francisco, USA
- UCSF Liver Center
| | - Emily Perito
- University of California, San Francisco, USA
- UCSF Liver Center
| | - Sandy Feng
- University of California, San Francisco, USA
- UCSF Liver Center
| | | | - Jennifer Lai
- University of California, San Francisco, USA
- UCSF Liver Center
| | | | - Ansgar W Lohse
- Medical Department, University Medical Center Hamburg-Eppendorf, Hamburg, DE
| | - Joseph DeRisi
- University of California, San Francisco, USA
- Chan Zuckerberg Biohub; San Francisco, CA, USA
| | - Michele Tana
- University of California, San Francisco, USA
- UCSF Liver Center
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2
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Campos-Murguia A, Henjes N, Loges S, Wedemeyer H, Jaeckel E, Taubert R, Engel B. Evaluation of immunoserological detection of anti-liver kidney microsomal, anti-soluble liver antigen and anti-mitochondrial antibodies. Sci Rep 2023; 13:10038. [PMID: 37340049 DOI: 10.1038/s41598-023-37095-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/15/2023] [Indexed: 06/22/2023] Open
Abstract
Autoantibodies are the diagnostic hallmark of autoimmune liver diseases. Indirect immunofluorescence (IFT) is the reference method for the detection of anti-mitochondrial antibodies (AMA) and anti-liver kidney microsomal type-1 (anti-LKM1) antibodies, and inhibition ELISA (iELISA) for anti-soluble liver antigen (anti-SLA) antibodies. Given the complexity of these techniques, commercial ELISAs have emerged as a practical alternative, but without head-to-head validations. This study evaluated the agreement between three commercial ELISAs and the reference techniques and the impact of polyreactive immunoglobulin G (pIgG), a recently described phenomenon in autoimmune hepatitis, on commercial ELISAs. Inter-rater reliability was assessed using Cohen-Kappa coefficient (κ). Forty-eight, 46, and 66 samples were analyzed for AMA, anti-LKM1, and anti-SLA, respectively. For AMA, one commercial assay showed high agreement (κ = 0.91 (0.78-1.00)) with the reference method, while the other two showed weak or moderate agreement. For anti-LKM1, only one commercial assay showed high agreement (κ = 0.86 (0.71-1.0)). For anti-SLA antibodies only moderate agreement was achieved (κ up to 0.71 (0.52-0.89)). There was a trend towards higher pIgG levels in false-positives in the commercial ELISAs. Patients with high suspicion of autoimmune liver diseases should be referred to reference laboratories with the capacity of performing gold standard methods if the initial ELISA-based screening was performed.
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Affiliation(s)
- Alejandro Campos-Murguia
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
| | - Nicole Henjes
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
| | - Stephanie Loges
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
| | - Elmar Jaeckel
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
- Ajmera Transplant Center, Toronto General Hospital, United Health Network, University of Toronto, Toronto, Canada
| | - Richard Taubert
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany
| | - Bastian Engel
- Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
- Member of the European Reference Network for Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany.
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3
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Czaja AJ. Incorporating the Molecular Mimicry of Environmental Antigens into the Causality of Autoimmune Hepatitis. Dig Dis Sci 2023:10.1007/s10620-023-07967-5. [PMID: 37160542 PMCID: PMC10169207 DOI: 10.1007/s10620-023-07967-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 05/01/2023] [Indexed: 05/11/2023]
Abstract
Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.
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Affiliation(s)
- Albert J Czaja
- Professor Emeritus of Medicine, Mayo Clinic College of Medicine and Science, 200 First Street SW, Rochester, MN, 55905, USA.
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4
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Dalekos GN, Gatselis NK. Autoimmune serology testing in clinical practice: An updated roadmap for the diagnosis of autoimmune hepatitis. Eur J Intern Med 2023; 108:9-17. [PMID: 36400668 DOI: 10.1016/j.ejim.2022.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/04/2022] [Accepted: 11/06/2022] [Indexed: 11/18/2022]
Abstract
Diagnosis of autoimmune hepatitis (AIH) is in most cases challenging for clinicians as there is not a single specific laboratory or histological marker to diagnose or exclude the presence of the disease. The clinical spectrum of AIH varies from completely asymptomatic to acute-severe or even rarely fulminant hepatic failure, while everybody can be affected irrespective of age, gender, and ethnicity. The old revised and the newer simplified diagnostic scores have been established by the International Autoimmune Hepatitis Group (IAIHG) in 1999 and 2008, respectively, which are based on several clinical, laboratory and histological parameters. Additionally, a thorough differential diagnosis from other diseases mimicking AIH is absolutely indicated. In this context, autoantibodies detection in patients with suspected AIH is mandatory -even though not pathognomonic- not only for AIH diagnosis but furthermore, for AIH classification (AIH-type 1 and AIH-type 2). Although autoimmune serology can be supportive of AIH diagnosis in ≥95% of cases if testing has been performed according to the IAIHG guidelines, this is not the case under real-life circumstances in routine clinical laboratories. Clinicians should be careful both for the importance of the required testing and how to interpret the results and therefore, they should communicate and discuss with the laboratory personnel to achieve the maximum benefit for the patient. Herein, a detailed and updated review of the diagnostic work-up for AIH diagnosis under real-life conditions is given to minimize the underestimation and misdiagnosis of AIH which can result in progression of the disease and unfavourable outcomes.
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Affiliation(s)
- George N Dalekos
- Department of Medicine and Research Laboratory of Internal Medicine, National Expertise Center of Greece in Autoimmune Liver Diseases, General University Hospital of Larissa, Larissa, Greece; European Reference Network on Hepatological Diseases (ERN RARE-LIVER), General University Hospital of Larissa, Larissa, Greece.
| | - Nikolaos K Gatselis
- Department of Medicine and Research Laboratory of Internal Medicine, National Expertise Center of Greece in Autoimmune Liver Diseases, General University Hospital of Larissa, Larissa, Greece; European Reference Network on Hepatological Diseases (ERN RARE-LIVER), General University Hospital of Larissa, Larissa, Greece
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5
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Challenges and opportunities in achieving effective regulatory T cell therapy in autoimmune liver disease. Semin Immunopathol 2022; 44:461-474. [PMID: 35641679 PMCID: PMC9256571 DOI: 10.1007/s00281-022-00940-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/15/2022] [Indexed: 12/29/2022]
Abstract
Autoimmune liver diseases (AILD) include autoimmune hepatitis (AIH), primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). These immune-mediated liver diseases involve a break down in peripheral self-tolerance with largely unknown aetiology. Regulatory T cells (Treg) are crucial in maintaining immunological tolerance. Hence, Treg immunotherapy is an attractive therapeutic option in AILD. Currently, AILD do not have a curative treatment option and patients take life-long immunosuppression or bile acids to control hepatic or biliary inflammation. Clinical investigations using good manufacturing practice (GMP) Treg in autoimmune liver disease have thus far demonstrated that Treg therapy is safe and that Treg migrate to inflamed liver tissue. For Treg immunotherapy to achieve efficacy in AILD, Treg must be retained within the liver and maintain their suppressive phenotype to dampen ongoing immune responses to hepatocytes and biliary epithelium. Therefore, therapeutic Treg subsets should be selected for tissue residency markers and maximal functionality. Optimisation of dosing regime and understanding longevity of Treg in vivo are critical to successful Treg therapy. It is also essential to consider combination therapy options to complement infused Treg, for instance low-dose interleukin-2 (IL-2) to support pre-existing and infused Treg survival and suppressive function. Understanding the hepatic microenvironment in both early- and late-stage AILD presents significant opportunity to better tailor Treg therapy in different patient groups. Modification of a hostile microenvironment to a more favourable one either prior to or during Treg therapy could enhance the efficacy and longevity of infused GMP-Treg. Applying recent technology to discovery of autoantigen responses in AILD, T cell receptor (TCR) sequencing and use of chimeric antigen receptor (CAR) technology represents the next frontier for disease-specific CAR-Treg therapies. Consideration of all these aspects in future trials and discovery research would position GMP Treg immunotherapy as a viable personalised-medicine treatment option for effective control of autoimmune liver diseases.
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6
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B cells in autoimmune hepatitis: bystanders or central players? Semin Immunopathol 2022; 44:411-427. [PMID: 35488094 PMCID: PMC9256567 DOI: 10.1007/s00281-022-00937-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/07/2022] [Indexed: 02/07/2023]
Abstract
B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.
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7
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Terziroli Beretta-Piccoli B, Mieli-Vergani G, Vergani D. Autoimmune Hepatitis: Serum Autoantibodies in Clinical Practice. Clin Rev Allergy Immunol 2022; 63:124-137. [PMID: 34491531 PMCID: PMC9464171 DOI: 10.1007/s12016-021-08888-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 01/13/2023]
Abstract
Circulating autoantibodies are a key diagnostic tool in autoimmune hepatitis (AIH), being positive in 95% of the cases if tested according to dedicated guidelines issued by the International Autoimmune Hepatitis Group. They also allow the distinction between type 1 AIH, characterized by positive anti-nuclear and/or anti-smooth muscle antibody, and type 2 AIH, characterized by positive anti-liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibody. Anti-soluble liver antigen is the only AIH-specific autoantibody, and is found in 20-30% of both type 1 and type 2 AIH. Anti-neutrophil cytoplasmic antibody is frequently positive in type 1 AIH, being associated also with inflammatory bowel disease and with primary/autoimmune sclerosing cholangitis. The reference method for autoantibody testing remains indirect immunofluorescence on triple tissue (rodent liver, kidney and stomach), allowing both the detection of the majority of liver-relevant reactivities, including those autoantibodies whose molecular target antigens are unknown. Of note, the current knowledge of the clinical significance of autoantibodies relies on studies based on this technique. However, immunofluorescence requires trained laboratory personnel, is observer-dependent, and lacks standardization, leading to ongoing attempts at replacing this method with automated assays, the sensitivity, and specificity of which, however, require further studies before they can be used as a reliable alternative to immunofluorescence; currently, they may be used as complementary to immunofluorescence.
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Affiliation(s)
- Benedetta Terziroli Beretta-Piccoli
- grid.29078.340000 0001 2203 2861Epatocentro Ticino & Facoltà Di Scienze Biomediche, Università Della Svizzera Italiana, Lugano, Switzerland ,grid.29078.340000 0001 2203 2861Institute for Research in Biomedicine, Bellinzona, Switzerland ,grid.46699.340000 0004 0391 9020King’s College London Faculty of Life Sciences &, Medicine At King’s College Hospital, London, UK
| | - Giorgina Mieli-Vergani
- grid.46699.340000 0004 0391 9020King’s College London Faculty of Life Sciences &, Medicine At King’s College Hospital, London, UK ,grid.46699.340000 0004 0391 9020Paediatric Liver, GI and Nutrition Centre, MowatLabs, King’s College Hospital, London, UK
| | - Diego Vergani
- grid.46699.340000 0004 0391 9020King’s College London Faculty of Life Sciences &, Medicine At King’s College Hospital, London, UK ,grid.46699.340000 0004 0391 9020Institute of Liver Studies, MowatLabs, King’s College Hospital, London, UK
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8
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Terziroli Beretta-Piccoli B, Mieli-Vergani G, Vergani D. The clinical usage and definition of autoantibodies in immune-mediated liver disease: A comprehensive overview. J Autoimmun 2018; 95:144-158. [DOI: 10.1016/j.jaut.2018.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023]
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9
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Rother M, Quitzke V. Selenoprotein synthesis and regulation in Archaea. Biochim Biophys Acta Gen Subj 2018; 1862:2451-2462. [DOI: 10.1016/j.bbagen.2018.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 01/23/2023]
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10
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Schulz L, Sebode M, Weidemann SA, Lohse AW. Variant syndromes of primary biliary cholangitis. Best Pract Res Clin Gastroenterol 2018; 34-35:55-61. [PMID: 30343711 DOI: 10.1016/j.bpg.2018.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/08/2018] [Indexed: 02/07/2023]
Abstract
Patients with primary biliary cholangitis (PBC) can show biochemical, serological and/or histological features of autoimmune hepatitis (AIH). The term 'AIH-PBC overlap syndrome' has been used frequently for these cases and implies the coexistence of two separate diseases. However, the boundaries between 'classical' PBC, PBC with features of AIH and 'classical' AIH are difficult to define, and therefore the term 'variant syndrome' should be preferred. A variant syndrome must primarily be assumed in PBC patients showing pronounced hepatitic activity, either expressed by elevated transaminases and raised levels of serum IgG/gammaglobulins or more specifically by liver biopsy showing a modified hepatitis activity index (mHAI) score of >4/18. The presence of AIH-specific autoantibodies also supports the diagnosis of a variant syndrome. The diagnosis must not be missed because individually adapted immunosuppressive treatment, analogous to AIH therapy, appears to have an important beneficial impact on the prognosis and should therefore be offered to these patients.
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Affiliation(s)
- Lisa Schulz
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Marcial Sebode
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sören A Weidemann
- Department of Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ansgar W Lohse
- I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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11
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Sebode M, Weiler-Normann C, Liwinski T, Schramm C. Autoantibodies in Autoimmune Liver Disease-Clinical and Diagnostic Relevance. Front Immunol 2018; 9:609. [PMID: 29636752 PMCID: PMC5880919 DOI: 10.3389/fimmu.2018.00609] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/12/2018] [Indexed: 12/12/2022] Open
Abstract
Testing for liver-related autoantibodies should be included in the workup of patients with hepatitis or cholestasis of unknown origin. Although most of these autoantibodies are not disease specific, their determination is a prerequisite to diagnose autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), and they are components of the diagnostic scoring system in these diseases. In primary sclerosing cholangitis (PSC), on the other hand, autoantibodies are frequently present but play a minor role in establishing the diagnosis. In PSC, however, data on antibodies suggest a link between disease pathogenesis and the intestinal microbiota. This review will focus on practical aspects of antibody testing in the three major autoimmune liver diseases AIH, PBC, and PSC.
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Affiliation(s)
- Marcial Sebode
- 1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Christina Weiler-Normann
- 1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Centre for Rare Diseases, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Timur Liwinski
- 1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Schramm
- 1st Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Centre for Rare Diseases, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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12
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Sebode M, Schulz L, Lohse AW. "Autoimmune(-Like)" Drug and Herb Induced Liver Injury: New Insights into Molecular Pathogenesis. Int J Mol Sci 2017; 18:ijms18091954. [PMID: 28895915 PMCID: PMC5618603 DOI: 10.3390/ijms18091954] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/04/2017] [Accepted: 09/08/2017] [Indexed: 12/12/2022] Open
Abstract
Idiosyncratic drug-induced liver injury (DILI) and hepatic injury due to herbal and dietary supplements (HDS) can adapt clinical characteristics of autoimmune hepatitis (AIH), such as the appearance of autoantibodies and infiltration of the liver by immune competent cells. To describe these cases of DILI/HDS, the poorly-defined term "autoimmune(-like)" DILI/HDS came up. It is uncertain if these cases represent a subgroup of DILI/HDS with distinct pathomechanistic and prognostic features different from "classical" DILI/HDS. Besides, due to the overlap of clinical characteristics of "immune-mediated" DILI/HDS and AIH, both entities are not easy to differentiate. However, the demarcation is important, especially with regard to treatment: AIH requires long-term, mostly lifelong immunosuppression, whereas DILI/HDS does not. Only through exact diagnostic evaluation, exclusion of differential diagnoses and prolonged follow-up can the correct diagnosis reliably be made. Molecular mechanisms have not been analysed for the subgroup of "autoimmune(-like)" DILI/HDS yet. However, several pathogenetic checkpoints of DILI/HDS in general and AIH are shared. An analysis of these shared mechanisms might hint at relevant molecular processes of "autoimmune(-like)" DILI/HDS.
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Affiliation(s)
- Marcial Sebode
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Lisa Schulz
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Ansgar W Lohse
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany.
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13
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The influence of genetic predisposition and autoimmune hepatitis inducing antigens in disease development. J Autoimmun 2017; 78:39-45. [DOI: 10.1016/j.jaut.2016.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 11/07/2016] [Accepted: 12/04/2016] [Indexed: 12/31/2022]
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14
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Manhas R, Gowri VS, Madhubala R. Leishmania donovani Encodes a Functional Selenocysteinyl-tRNA Synthase. J Biol Chem 2015; 291:1203-20. [PMID: 26586914 DOI: 10.1074/jbc.m115.695007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Indexed: 11/06/2022] Open
Abstract
The synthesis of selenocysteine, the 21st amino acid, occurs on its transfer RNA (tRNA), tRNA(Sec). tRNA(Sec) is initially aminoacylated with serine by seryl-tRNA synthetase and the resulting seryl moiety is converted to phosphoserine by O-phosphoseryl-tRNA kinase (PSTK) in eukaryotes. The selenium donor, selenophosphate is synthesized from selenide and ATP by selenophosphate synthetase. Selenocysteinyl-tRNA synthase (SepSecS) then uses the O-phosphoseryl-tRNA(Sec) and selenophosphate to form Sec-tRNA(Sec) in eukaryotes. Here, we report the characterization of selenocysteinyl-tRNA synthase from Leishmania donovani. Kinetoplastid SepSecS enzymes are phylogenetically closer to worm SepSecS. LdSepSecS was found to exist as a tetramer. Leishmania SepSecS enzyme was found to be active and able to complement the ΔselA deletion in Escherichia coli JS1 strain only in the presence of archaeal PSTK, indicating the conserved nature of the PSTK-SepSecS pathway. LdSepSecS was found to localize in the cytoplasm of the parasite. Gene deletion studies indicate that Leishmania SepSecS is dispensable for the parasite survival. The parasite was found to encode three selenoproteins, which were only expressed in the presence of SepSecS. Selenoproteins of L. donovani are not required for the growth of the promastigotes. Auranofin, a known inhibitor of selenoprotein synthesis showed the same sensitivity toward the wild-type and null mutants suggesting its effect is not through binding to selenoproteins. The three-dimensional structural comparison indicates that human and Leishmania homologs are structurally highly similar but their association modes leading to tetramerization seem different.
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Affiliation(s)
- Reetika Manhas
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Rentala Madhubala
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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15
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Zachou K, Gampeta S, Gatselis NK, Oikonomou K, Goulis J, Manoussakis MN, Renaudineau Y, Bogdanos DP, Dalekos GN. Anti-SLA/LP alone or in combination with anti-Ro52 and fine specificity of anti-Ro52 antibodies in patients with autoimmune hepatitis. Liver Int 2015; 35:660-72. [PMID: 25113420 DOI: 10.1111/liv.12658] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/05/2014] [Indexed: 02/13/2023]
Abstract
BACKGROUND & AIMS Antibodies (Abs) to soluble liver antigen/liver pancreas (anti-SLA/LP) are considered markers of worse prognosis and outcome in patients with autoimmune hepatitis (AIH) although this assumption has recently been attributed to their frequent co-expression with Abs against Ro52 (anti-Ro52). To assess the clinical significance of anti-SLA/LP Abs alone or in combination with anti-Ro52 in AIH patients and determine the immunodominant Ro52 epitopes according to the anti-SLA/LP status. METHODS Twenty-three anti-SLA/LP-positive and 106 anti-SLA/LP-negative AIH patients were included. Anti-SLA/LP were determined by ELISA using recombinant antigen, and confirmed by immunoblot using cytosolic rat liver fraction or HuH-7 extract. Anti-Ro52 Abs were determined by ELISA using recombinant antigen. Epitope mapping was assessed by ELISA using overlapping peptides covering the whole Ro52 protein in 26 AIH patients and 12 patients with Sjögren's syndrome. RESULTS Anti-SLA/LP positivity was not associated with the clinical, laboratory or histological characteristics of AIH patients. Treatment response, corticosteroid withdrawal, relapse after stopping treatment and outcome, were not associated with the presence of anti-SLA/LP, anti-Ro52 or double reactivity. Moreover, Ro52 epitope mapping revealed new epitopes unique for AIH and independent from anti-SLA/LP positivity. CONCLUSIONS Neither anti-SLA/LP nor anti-Ro52 Abs or their combination could specify a distinct group of AIH patients in terms of clinical characteristics, treatment response and outcome. Further studies are needed to clarify whether the newly discovered immunodominant epitopes of Ro52 antigen which were associated specifically with AIH have any clinical or pathogenetic significance in AIH.
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Affiliation(s)
- Kalliopi Zachou
- Department of Medicine and Research Laboratory of Internal Medicine, School of Medicine, University of Thessaly, Larissa, Greece
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Gatselis NK, Zachou K, Koukoulis GK, Dalekos GN. Autoimmune hepatitis, one disease with many faces: Etiopathogenetic, clinico-laboratory and histological characteristics. World J Gastroenterol 2015; 21:60-83. [PMID: 25574080 PMCID: PMC4284362 DOI: 10.3748/wjg.v21.i1.60] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/30/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023] Open
Abstract
Autoimmune hepatitis (AIH) is an unresolving progressive liver disease of unknown etiology characterized by hypergammaglobulinemia, autoantibodies detection and interface hepatitis. Due to the absence of specific diagnostic markers and the large heterogeneity of its clinical, laboratory and histological features, AIH diagnosis may be potentially difficult. Therefore, in this in-depth review we summarize the substantial progress on etiopathogenesis, clinical, serological and histological phenotypes of AIH. AIH has a global distribution affecting any age, both sexes and all ethnic groups. Clinical manifestations vary from asymptomatic to severe or rarely fulminant hepatitis. Hypergammaglobulinemia with selective elevation of IgG is found in most cases. Autoimmune attack is perpetuated, possibly via molecular mimicry, and favored by the impaired control of T-regulatory cells. Histology (interface hepatitis, emperipolesis and hepatic rosette formation) and autoantibodies detection although not pathognomonic, are still the hallmark for a timely diagnosis. AIH remains a major diagnostic challenge. AIH should be considered in every case in the absence of viral, metabolic, genetic and toxic etiology of chronic or acute hepatitis. Laboratory personnel, hepato-pathologists and clinicians need to become more familiar with disease expressions and the interpretation of liver histology and autoimmune serology to derive maximum benefit for the patient.
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Zachou K, Muratori P, Koukoulis GK, Granito A, Gatselis N, Fabbri A, Dalekos GN, Muratori L. Review article: autoimmune hepatitis -- current management and challenges. Aliment Pharmacol Ther 2013; 38:887-913. [PMID: 24010812 DOI: 10.1111/apt.12470] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 03/22/2013] [Accepted: 08/12/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND Autoimmune hepatitis (AIH) is a disease of unknown aetiology characterised by interface hepatitis, hypergammaglobulinaemia, circulating autoantibodies and a favourable response to immunosuppression. AIM To review recent advancements in understanding aetiopathogenesis, clinical, serological and histological features, diagnostic criteria and treatment strategies of AIH. METHODS Published studies on AIH extracted mainly from PubMed during the last 15 years. RESULTS Autoimmune hepatitis has a global distribution affecting any age, both sexes and all ethnic groups. Clinical manifestations are variable ranging from no symptoms to severe acute hepatitis and only seldom to fulminant hepatic failure. Autoimmune attack is perpetuated, possibly via molecular mimicry mechanisms, and favoured by the impaired control of regulatory T-cells. A typical laboratory finding is hypergammaglobulinaemia with selective elevation of IgG, although in 15-25% of patients - particularly children, elderly and acute cases - IgG levels are normal. Liver histology and autoantibodies, although not pathognomonic, still remain the hallmark for diagnosis. Immunosuppressive treatment is mandatory and life-saving; however, to meet strict response criteria, the conventional therapy with prednisolone with or without azathioprine is far from ideal. CONCLUSIONS Autoimmune hepatitis remains a major diagnostic and therapeutic challenge. The clinician, the hepato-pathologist and the laboratory personnel need to become more familiar with different expressions of the disease, interpretation of liver histology and autoimmune serology. According to the strict definition of treatment response issued by the 2010 AASLD guidelines, many patients are nonresponders to conventional treatment. Newer immunosuppressive agents targeting pathogenetic mechanisms can improve patient management, which needs to be tailored on a case-by-case basis.
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Affiliation(s)
- K Zachou
- Department of Medicine and Research Laboratory of Internal Medicine, Medical School, Thessaly University, Larissa, Greece
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18
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Paiardini A, Pascarella S. Structural mimicry between SLA/LP and Rickettsia surface antigens as a driver of autoimmune hepatitis: insights from an in silico study. Theor Biol Med Model 2013; 10:25. [PMID: 23575112 PMCID: PMC3636016 DOI: 10.1186/1742-4682-10-25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 04/07/2013] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Autoimmune hepatitis (AIH) is a chronic, progressive liver disease, characterized by continuing hepatocellular inflammation and necrosis. A subgroup of AIH patients presents specific autoantibodies to soluble liver antigen/liver-pancreas (SLA/LP) protein, which is regarded as a highly specific diagnostic marker. Autoantigenic SLA/LP peptides are targeted by CD4+ T cells, and restricted by the allele HLA-DRB1*03:01, which confers disease susceptibility in Europeans and Americans. A positively charged residue at position 71 has been indicated as critical for AIH susceptibility in all of the HLA alleles identified to date. Though the exact molecular mechanisms underlying pathogenesis of AIH are not clear, molecular mimicry between SLA/LP and viral/bacterial antigens has been invoked. METHODS The immunodominant region of SLA/LP was used as query in databank searches to identify statistically significant similarities with viral/bacterial peptides. Homology modeling and docking was used to investigate the potential interaction of HLA-DRB1*03:01 with the identified peptides. By molecular mechanics means, the interactions and energy of binding at the HLA binding site was also scrutinized. RESULTS A statistically significant structural similarity between the immunodominant regions of SLA/LP and a region of the surface antigen PS 120 from Rickettsia spp. has been detected. The interaction of the SLA/LP autoepitope and the corresponding Rickettsia sequence with the allele HLA-DRB1*03:01 has been simulated. The obtained results predict for both peptides a similar binding mode and affinity to HLA-DRB1*03:01. A "hot spot" of interaction between HLA-DRB1*03:01 and PS 120 is located at the P4 binding pocket, and is represented by a salt bridge involving Lys at position 71 of the HLA protein, and Glu 795 of PS120 peptide. CONCLUSIONS These findings strongly support the notion that a molecular mimicry mechanism can trigger AIH onset. CD4+ T cells recognizing peptides of SLA/LP could indeed cross-react with foreign Rickettsia spp. antigens. Finally, the same analysis suggests a molecular explanation for the importance of position 71 in conferring the susceptibility of the allele HLA-DRB1*03:01 to AIH. The lack of a positive charge at such position could prevent HLA alleles from binding the foreign peptides and triggering the molecular mimicry event.
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Affiliation(s)
- Alessandro Paiardini
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza - Università di Roma, Roma, 00185, Italy
| | - Stefano Pascarella
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza - Università di Roma, Roma, 00185, Italy
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19
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Zhao Y, Zhang Y, Liu YM, Liu Y, Feng X, Liao HY, Vergani D, Ma Y, Yan HP. Identification of T cell epitopes on soluble liver antigen in Chinese patients with auto-immune hepatitis. Liver Int 2011; 31:721-9. [PMID: 21457445 DOI: 10.1111/j.1478-3231.2011.02487.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIM To identify soluble liver antigen (SLA)-specific dominant epitopes and analyse the correlation between SLA-specific T cell response and the status of the disease. METHODS A cross-sectional analysis of SLA-specific T cell responses to 54 overlapping peptides covering the entire SLA sequence was performed using an interferon (IFN)-γ ELISpot assay in 31 patients with auto-immune hepatitis (AIH)-1, 15 patients with primary biliary cirrhosis, 16 hepatitis B virus, seven hepatitis C virus infection and 10 healthy subjects, in order to assess the correlation between SLA-specific T cell responses and the clinical outcome. RESULTS Soluble liver antigen-specific IFN-γ responses in AIH were significantly more frequent in AIH patients (58.1%) than those in controls (6.7% in PBC, P=0.001; 4.3% in hepatitis B/C, P<0.001 and 0% in healthy subjects, P=0.0015). Among 31 AIH patients, the frequency of recognition and the magnitude of response to SLA peptides in anti-SLA antibody-positive patients were higher and stronger than those negative for anti-SLA antibodies (P=0.02 and 0.037 respectively). We further analysed T-cell restriction and found that six individual SLA peptides (4, 9, 11, 12, 41 and 44) were recognized by CD4 T cells, and the most frequently recognized peptides were peptides 12 (61.1% of participants), followed by peptide 4 and peptide 44 (55.6 and 38.9% respectively). Moreover, a positive association was found between the breadth of recognition of SLA peptides and the indices of liver damage. CONCLUSION T cell response to SLA in Chinese patients with AIH is broad and associated with hepatocyte damage.
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Affiliation(s)
- Yan Zhao
- Clinical Research Centre for Autoimmune Liver Disease, Beijing YouAn Hospital, Capital Medical University, Beijing, China
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20
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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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21
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Muratori L, Muratori P, Granito A, Pappas G, Cassani F, Lenzi M. Current topics in autoimmune hepatitis. Dig Liver Dis 2010; 42:757-64. [PMID: 20615766 DOI: 10.1016/j.dld.2010.05.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 05/23/2010] [Accepted: 05/31/2010] [Indexed: 12/11/2022]
Abstract
Autoimmune hepatitis is a chronic liver disease of unknown aetiology characterized by interface hepatitis, hypergammaglobulinaemia and circulating autoantibodies. In the last decade a number of advancements have been made in the field of clinical and basic research: the simplified diagnostic criteria, the complete response defined as normalization of transaminase levels, the molecular identification of the antigenic targets of anti-liver cytosol antibody type 1 and anti-soluble liver antigen, the detection of anti-actin antibodies, the description of de novo autoimmune hepatitis after liver transplantation for non-autoimmune liver diseases, the characterization of autoimmune hepatitis with overlapping features of primary biliary cirrhosis or primary sclerosing cholangitis, the preliminary experience with novel treatment strategies based on cyclosporine, mycophenolate mofetil and budesonide, the role played by "impaired" regulatory T cells and the development of novel animal models of autoimmune hepatitis.
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Affiliation(s)
- Luigi Muratori
- Department of Clinical Medicine, Alma Mater Studiorum - University of Bologna, Policlinico Sant'Orsola-Malpighi, Padiglione 11, Bologna, Italy.
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22
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Czaja AJ. Autoantibodies as prognostic markers in autoimmune liver disease. Dig Dis Sci 2010; 55:2144-61. [PMID: 20464491 DOI: 10.1007/s10620-010-1268-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 04/23/2010] [Indexed: 01/25/2023]
Abstract
Certain autoantibodies in autoimmune liver disease have prognostic implications that are under-utilized and under-developed. The goals of this review are to indicate progress in characterizing the autoantibodies with prognostic connotations and to indicate the feasibility and importance of discovering other markers. Prime source and review articles in English were selected by a Medline search through 2010. Antibodies to soluble liver antigen, actin, liver cytosol type 1, asialoglycoprotein receptor, chromatin, cyclic citrullinated peptide, and uridine glucuronosyltransferases have been associated with the occurrence, severity, and progression of autoimmune hepatitis, and antibodies to Sp100, gp210, and centromere have had similar implications in primary biliary cirrhosis. Antibodies to soluble liver antigen have shown the most promise in autoimmune hepatitis as they have been associated with severe histological changes, long durations of treatment, relapse after drug withdrawal, and high frequency of liver failure. Antibodies to the nuclear rim pore protein, gp210, have shown the most promise in primary biliary cirrhosis as they have been associated with severe interface hepatitis, lobular inflammation, and progression to liver failure. The major limitations of the autoantibodies have been their lack of standardized assays, low negative predictabilities, and fluctuating levels. Performance parameters will improve as critical pathogenic pathways, comprehensive testing batteries, and standardized assays through international exchange workshops are developed. Progress has been made in identifying the serological markers of prognosis in autoimmune liver disease, and they promise to reflect critical disease mechanisms and enhance patient management.
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Affiliation(s)
- Albert J Czaja
- Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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23
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Volkmann M, Luithle D, Zentgraf H, Schnölzer M, Fiedler S, Heid H, Schulze-Bergkamen A, Strassburg CP, Gehrke SG, Manns MP. SLA/LP/tRNP((Ser)Sec) antigen in autoimmune hepatitis: identification of the native protein in human hepatic cell extract. J Autoimmun 2009; 34:59-65. [PMID: 19683415 DOI: 10.1016/j.jaut.2009.07.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 07/02/2009] [Accepted: 07/23/2009] [Indexed: 01/03/2023]
Abstract
A diagnostic subgroup of AIH type 1 is characterized by specific serum antibodies against soluble liver protein. The respective autoantigen was named SLA/LP/tRNP((Ser)Sec), after three homologous recombinant polypeptides were isolated from expression gene libraries. We analyzed human cultured liver cells for the human homologue of recombinant SLA/LP/tRNP((Ser)Sec) by antigen purification. In addition, a monoclonal antibody was generated against recombinant SLA-p35, a truncated recombinant SLA-reactive polypeptide. With a positive patient serum, immune affinity chromatography was performed on the 52 kD-SLA main antigenic determinant pre-enriched by ion exchange chromatography. By mass spectrometry, the 52 kD-SLA/LP/tRNP ((Ser)Sec) autoantigen was unambiguously identified in the purification product. The identity of the recombinant SLA-p35 and its human homologue was further confirmed by a specific signal of the anti SLA-p35 monoclonal antibody with purified human SLA/LP/tRNP((Ser)Sec). The 48 kD-SLA species frequently comigrating in SLA-immunoblotting however was not identified by either approach. We conclude that the native counterpart of recombinant tRNP((Ser)(Sec)) indeed is detectable with a molecular weight of 52 kD in soluble liver extract of human cells as the major antigenic component of SLA/LP/tRNP((Ser)Sec).
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MESH Headings
- Amino Acid Sequence
- Antibodies, Monoclonal/metabolism
- Autoantigens/blood
- Autoantigens/genetics
- Autoantigens/immunology
- Autoantigens/metabolism
- Cell Extracts
- Cell Line, Tumor
- Chromatography, Affinity
- Cloning, Molecular
- Hepatitis, Autoimmune/blood
- Hepatitis, Autoimmune/diagnosis
- Hepatitis, Autoimmune/immunology
- Hepatitis, Autoimmune/metabolism
- Hepatocytes/immunology
- Hepatocytes/metabolism
- Hepatocytes/pathology
- Humans
- Mass Spectrometry
- Molecular Sequence Data
- Peptide Fragments/blood
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- RNA, Transfer, Amino Acyl/blood
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/immunology
- RNA, Transfer, Amino Acyl/metabolism
- Recombinant Proteins/blood
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
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Affiliation(s)
- Martin Volkmann
- Labor Prof. Dr. H.-P. Seelig und Kollegen, Karlsruhe, Germany.
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24
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Stock T, Rother M. Selenoproteins in Archaea and Gram-positive bacteria. Biochim Biophys Acta Gen Subj 2009; 1790:1520-32. [PMID: 19344749 DOI: 10.1016/j.bbagen.2009.03.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 03/23/2009] [Accepted: 03/23/2009] [Indexed: 01/23/2023]
Abstract
Selenium is an essential trace element for many organisms by serving important catalytic roles in the form of the 21st co-translationally inserted amino acid selenocysteine. It is mostly found in redox-active proteins in members of all three domains of life and analysis of the ever-increasing number of genome sequences has facilitated identification of the encoded selenoproteins. Available data from biochemical, sequence, and structure analyses indicate that Gram-positive bacteria synthesize and incorporate selenocysteine via the same pathway as enterobacteria. However, recent in vivo studies indicate that selenocysteine-decoding is much less stringent in Gram-positive bacteria than in Escherichia coli. For years, knowledge about the pathway of selenocysteine synthesis in Archaea and Eukarya was only fragmentary, but genetic and biochemical studies guided by analysis of genome sequences of Sec-encoding archaea has not only led to the characterization of the pathways but has also shown that they are principally identical. This review summarizes current knowledge about the metabolic pathways of Archaea and Gram-positive bacteria where selenium is involved, about the known selenoproteins, and about the respective pathways employed in selenoprotein synthesis.
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Affiliation(s)
- Tilmann Stock
- Molekulare Mikrobiologie und Bioenergetik, Institut für Molekulare Biowissenschaften, Goethe-Universität Frankfurt am Main, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
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25
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Mix H, Weiler-Normann C, Thimme R, Ahlenstiel G, Shin EC, Herkel J, David CS, Lohse AW, Rehermann B. Identification of CD4 T-cell epitopes in soluble liver antigen/liver pancreas autoantigen in autoimmune hepatitis. Gastroenterology 2008; 135:2107-18. [PMID: 18773898 PMCID: PMC2708941 DOI: 10.1053/j.gastro.2008.07.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 07/14/2008] [Accepted: 07/17/2008] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease associated with autoantibodies and liver-infiltrating lymphocytes. Although autoantibodies are tested routinely to diagnose and classify AIH, liver-infiltrating lymphocytes are regarded as the primary factor for disease pathogenesis. The purpose of this study was to identify and characterize autoantigenic peptides within human AIH-specific soluble liver antigen/liver pancreas antigen (SLA/LP) that are targeted by CD4(+) T cells and restricted by the disease susceptibility gene HLA-DRB1*0301. METHODS HLA-DRB1*0301 transgenic mice were immunized with SLA/LP. Antibody and T-cell responses were analyzed with SLA/LP-overlapping peptides in enzyme immunoassay, proliferation, and enzyme-linked immunospot (ELISpot) assays. Minimal optimal T-cell epitopes were identified, characterized with cloned T-cell hybridomas, and confirmed in tetramer and ELISpot assays with AIH patients' peripheral blood mononuclear cells. RESULTS All mice developed SLA/LP-specific IgG1/IgG2a antibodies against the same SLA/LP peptides as human beings. T cells targeted several peptides within SLA/LP, 2 of which were DR3-restricted and one overlapped the sequence recognized by human autoantibodies. Minimal optimal epitopes were mapped, DRB1*0301/epitope-tetramers were generated, and the frequency and function of HLA-DRB1*0301-restricted autoantigen-specific T cells in AIH patients were analyzed with tetramer and interferon-gamma ELISpot assays. CONCLUSIONS This study identified T-cell epitopes within SLA/LP, restricted by the disease susceptibility gene DRB1*0301 and in close proximity to the human autoantibody epitope. These results and the generated reagents now provide the opportunity to directly monitor autoreactive T cells in AIH patients in clinical studies.
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Affiliation(s)
- Heiko Mix
- Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, MD 20892
| | - Christina Weiler-Normann
- Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, MD 20892, I. Medizinische Klinik, Universitätsklinikum Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Robert Thimme
- Abteilung Innere Medizin II, Medizinische Universitätsklinik, 79106 Freiburg, Germany
| | - Golo Ahlenstiel
- Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, MD 20892
| | - Eui-Cheol Shin
- Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, MD 20892
| | - Johannes Herkel
- I. Medizinische Klinik, Universitätsklinikum Hamburg Eppendorf, 20246 Hamburg, Germany, I. Medizinische Klinik, Johannes Gutenberg Universität, 55101 Mainz, Germany
| | - Chella S. David
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Ansgar W. Lohse
- I. Medizinische Klinik, Universitätsklinikum Hamburg Eppendorf, 20246 Hamburg, Germany, I. Medizinische Klinik, Johannes Gutenberg Universität, 55101 Mainz, Germany
| | - Barbara Rehermann
- Immunology Section, Liver Diseases Branch, NIDDK, National Institutes of Health, DHHS, Bethesda, MD 20892
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26
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Affiliation(s)
- David G Bowen
- A.W. Morrow Gastroenterology and Liver Centre, Centenary Institute, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
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27
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Hennes EM, Zeniya M, Czaja AJ, Parés A, Dalekos GN, Krawitt EL, Bittencourt PL, Porta G, Boberg KM, Hofer H, Bianchi FB, Shibata M, Schramm C, Eisenmann de Torres B, Galle PR, McFarlane I, Dienes HP, Lohse AW. Simplified criteria for the diagnosis of autoimmune hepatitis. Hepatology 2008; 48:169-76. [PMID: 18537184 DOI: 10.1002/hep.22322] [Citation(s) in RCA: 1162] [Impact Index Per Article: 72.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Diagnosis of autoimmune hepatitis (AIH) may be challenging. However, early diagnosis is important because immunosuppression is life-saving. Diagnostic criteria of the International Autoimmune Hepatitis Group (IAIHG) were complex and purely meant for scientific purposes. This study of the IAIHG aims to define simplified diagnostic criteria for routine clinical practice. Candidate criteria included sex, age, autoantibodies, immunoglobulins, absence of viral hepatitis, and histology. The training set included 250 AIH patients and 193 controls from 11 centers worldwide. Scores were built from variables showing predictive ability in univariate analysis. Diagnostic value of each score was assessed by the area under the receiver operating characteristic (ROC) curve. The best score was validated using data of an additional 109 AIH patients and 284 controls. This score included autoantibodies, immunoglobulin G, histology, and exclusion of viral hepatitis. The area under the curve for prediction of AIH was 0.946 in the training set and 0.91 in the validation set. Based on the ROC curves, two cutoff points were chosen. The score was found to have 88% sensitivity and 97% specificity (cutoff > or =6) and 81% sensitivity and 99% specificity (cutoff > or =7) in the validation set. CONCLUSION A reliable diagnosis of AIH can be made using a very simple diagnostic score. We propose the diagnosis of probable AIH at a cutoff point greater than 6 points and definite AIH 7 points or higher.
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Affiliation(s)
- Elke M Hennes
- Department of Medicine, University Medical Centre Hamburg Eppendorf, Germany
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28
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Araiso Y, Palioura S, Ishitani R, Sherrer RL, O'Donoghue P, Yuan J, Oshikane H, Domae N, Defranco J, Söll D, Nureki O. Structural insights into RNA-dependent eukaryal and archaeal selenocysteine formation. Nucleic Acids Res 2007; 36:1187-99. [PMID: 18158303 PMCID: PMC2275076 DOI: 10.1093/nar/gkm1122] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The micronutrient selenium is present in proteins as selenocysteine (Sec). In eukaryotes and archaea, Sec is formed in a tRNA-dependent conversion of O-phosphoserine (Sep) by O-phosphoseryl-tRNA:selenocysteinyl-tRNA synthase (SepSecS). Here, we present the crystal structure of Methanococcus maripaludis SepSecS complexed with PLP at 2.5 Å resolution. SepSecS, a member of the Fold Type I PLP enzyme family, forms an (α2)2 homotetramer through its N-terminal extension. The active site lies on the dimer interface with each monomer contributing essential residues. In contrast to other Fold Type I PLP enzymes, Asn247 in SepSecS replaces the conserved Asp in binding the pyridinium nitrogen of PLP. A structural comparison with Escherichia coli selenocysteine lyase allowed construction of a model of Sep binding to the SepSecS catalytic site. Mutations of three conserved active site arginines (Arg72, Arg94, Arg307), protruding from the neighboring subunit, led to loss of in vivo and in vitro activity. The lack of active site cysteines demonstrates that a perselenide is not involved in SepSecS-catalyzed Sec formation; instead, the conserved arginines may facilitate the selenation reaction. Structural phylogeny shows that SepSecS evolved early in the history of PLP enzymes, and indicates that tRNA-dependent Sec formation is a primordial process.
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Affiliation(s)
- Yuhei Araiso
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa 226-8501, Japan
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Herkel J, Manns MP, Lohse AW. Selenocysteine, soluble liver antigen/liver-pancreas, and autoimmune hepatitis. Hepatology 2007; 46:275-7. [PMID: 17596869 DOI: 10.1002/hep.21807] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Johannes Herkel
- Department of Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
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Wang CX, Teufel A, Cheruti U, Grötzinger J, Galle PR, Lohse AW, Herkel J. Characterization of human gene encoding SLA/LP autoantigen and its conserved homologs in mouse, fish, fly, and worm. World J Gastroenterol 2006; 12:902-7. [PMID: 16521218 PMCID: PMC4066155 DOI: 10.3748/wjg.v12.i6.902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To approach the elusive function of the SLA/LP molecule, we have characterized genomic organization and conservation of the major antigenic and functional properties of the SLA/LP molecule in various species.
METHODS: By means of computational biology, we have characterized the complete SLA/LP gene, mRNA and deduced protein sequences in man, mouse, zebrafish, fly, and worm.
RESULTS: The human SLA/LP gene sequence of approximately 39 kb, which maps to chromosome 4p15.2, is organized in 11 exons, of which 10 or 11 are translated, depending on the splice variant. Homologous molecules were identified in several biological model organisms. The various homologous protein sequences showed a high degree of similarity or homology, notably at those residues that are of functional importance. The only domain of the human protein sequence that lacks significant homology with homologous sequences is the major antigenic epitope recognized by autoantibodies from autoimmune hepatitis (AIH) patients.
CONCLUSION: The SLA/LP molecule and its functionally relevant residues have been highly conserved throughout the evolution, suggesting an indispensable function of the molecule. The finding that the only non-conserved domain is the dominant antigenic epitope of the human SLA/LP sequence, suggests that SLA/LP autoimmunity is autoantigen-driven rather than being driven by molecular mimicry.
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Affiliation(s)
- Chun-Xia Wang
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
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Abstract
Autoimmune liver disease in children presents predominantly as autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC). These diagnoses must be considered in patients who have acute and chronic hepatitis, particularly when an extrahepatic autoimmune disorder is present. In AIH, the timely and sustained control of liver inflammation is critical to improve the short- and long-term outcomes. No effective treatment for PSC has been identified to date, but supportive care, careful attention to complications and associated nonhepatic diseases, and liver transplantation significantly improve the long-term outcome.
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Affiliation(s)
- Fernando Alvarez
- Department of Pediatrics, Hôpital Sainte-Justine, University of Montreal, 3175 Côte Sainte-Catherine, Montreal, Québec H3T 1C5, Canada.
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Abstract
In 1950, Waldenström was the first to describe a chronic form of hepatitis in young women. Subsequently, the disease was found to be associated with other autoimmune syndromes and was later termed "lupoid hepatitis" because of the presence of antinuclear antibodies. In 1965, it became designated by Mackay et al. as "autoimmune hepatitis" at an international meeting, at which the general concept of autoimmunity was endorsed by the scientific community. In the early 1960s and 1970s, the value of immunosuppressive therapy with glucocorticoids and/or azathioprine was well documented in several studies. The original association of autoimmune hepatitis (AIH) and HLA alleles, which has remarkably stood the test of time, was published in 1972. In the 1970s and 1980s, several autoantibodies were identified in patients with autoimmune hepatitis directed against proteins of the endoplasmatic reticulum expressed in liver and kidney and against soluble liver antigens. Subsequently, the molecular targets of these antibodies were identified and more precisely characterized. In the last two decades many additional pieces of the AIH puzzle have been collected leading to the identification of additional antibodies and genes associated with AIH and to the emergence of new therapeutic agents. Meanwhile, the immunoserological and genetic heterogeneity of AIH is well established and it has become obvious that clinical manifestations, disease behavior, and treatment outcome may vary by racial groups, geographical regions and genetic predisposition. Currently, the International Autoimmune hepatitis group is endorsing multi-center collaborative studies to more precisely define the features at disease presentation and to define prognostic indices and appropriate treatment algorithms. Given the importance of serological testing, the IAHG is also working on guidelines and procedures for more reliable and standardized testing of autoantibodies.
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Affiliation(s)
- Michael P Manns
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Germany.
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Affiliation(s)
- Edward L Krawitt
- Department of Medicine, University of Vermont, Burlington, VT 05405-0068, USA.
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Peters B, Sidney J, Bourne P, Bui HH, Buus S, Doh G, Fleri W, Kronenberg M, Kubo R, Lund O, Nemazee D, Ponomarenko JV, Sathiamurthy M, Schoenberger SP, Stewart S, Surko P, Way S, Wilson S, Sette A. The design and implementation of the immune epitope database and analysis resource. Immunogenetics 2005; 57:326-36. [PMID: 15895191 PMCID: PMC4780685 DOI: 10.1007/s00251-005-0803-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 04/22/2005] [Indexed: 01/13/2023]
Abstract
Epitopes are defined as parts of antigens interacting with receptors of the immune system. Knowledge about their intrinsic structure and how they affect the immune response is required to continue development of techniques that detect, monitor, and fight diseases. Their scientific importance is reflected in the vast amount of epitope-related information gathered, ranging from interactions between epitopes and major histocompatibility complex molecules determined by X-ray crystallography to clinical studies analyzing correlates of protection for epitope based vaccines. Our goal is to provide a central resource capable of capturing this information, allowing users to access and connect realms of knowledge that are currently separated and difficult to access. Here, we portray a new initiative, "The Immune Epitope Database and Analysis Resource." We describe how we plan to capture, structure, and store this information, what query interfaces we will make available to the public, and what additional predictive and analytical tools we will provide.
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Affiliation(s)
- Bjoern Peters
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - John Sidney
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Phil Bourne
- San Diego Supercomputer Center, P.O.Box 85608 San Diego, CA, 92186-5608, USA
| | - Huynh-Hoa Bui
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Soeren Buus
- University of Copenhagen, Panum Building 18.3.22, Bleadamsvei 3, 220 Copenhagen, Denmark
| | - Grace Doh
- SH Grace Consulting, A-402 Hannam Riverhill, 390 Hannam-dong, Youngsan-ku, Seoul, 140-210, South Korea
| | - Ward Fleri
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Mitch Kronenberg
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Ralph Kubo
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Ole Lund
- BioCentrum-DTU, Technical University of Denmark, Building 208, Lyngby, 2800, Denmark
| | - David Nemazee
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, IMM-29, La Jolla, CA, 92037, USA
| | | | - Muthu Sathiamurthy
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Stephen P. Schoenberger
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
| | - Scott Stewart
- Science Applications International Corporation, 9455 Towne Center Drive, MS-W2, San Diego, CA, 92121, USA
| | - Pamela Surko
- Science Applications International Corporation, 9455 Towne Center Drive, MS-W2, San Diego, CA, 92121, USA
| | - Scott Way
- Science Applications International Corporation, 9455 Towne Center Drive, MS-W2, San Diego, CA, 92121, USA
| | - Steve Wilson
- La Jolla Institute of Allergy and Immunology, 3030 Bunker Hill Street, Suite 326, San Diego, CA, 92109, USA
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Abstract
Autoimmune hepatitis can affect diverse ethnic groups, and its clinical expression and outcome can vary accordingly. An asymptomatic presentation may identify patients who respond more readily to medication. Celiac sprue is important to recognize and treat by gluten restriction. Centrilobular necrosis and coincidental destructive cholangitis do not preclude the diagnosis, and antibodies to soluble liver antigen/liver pancreas may identify patients susceptible to relapse. Women, who have non-DRB1*0401 DR4 alleles more commonly than do men, may respond to a diverse range of autoantigens. DRB1*1301 is associated with autoimmune hepatitis in Brazil, especially among children, and it may favor an indigenous triggering agent. Variant syndromes are heterogenous conditions that probably reflect referral biases, and molecular mimicry between foreign and self-antigens is the basis for most theories of pathogenesis. Immunosuppressive medications (eg, cyclosporine, mycophenolate mofetil) have been used empirically with success, and recurrent and de novo disease after liver transplantation must be considered in all patients with graft dysfunction.
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Affiliation(s)
- Albert J Czaja
- Division of Gastroenterology and Hepatology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
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Affiliation(s)
- Fernando Alvarez
- Hopital Ste. Justine and University of Montreal, Montreal, Quebec, Canada
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38
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Ballot E, Bruneel A, Johanet C, Yamamoto AM. Prevalence and clinical relevance of anti-soluble liver antigen (SLA) antibodies in autoimmune hepatitis. Hepatology 2002; 36:765-6; author reply 766-7. [PMID: 12198675 DOI: 10.1053/jhep.2002.34440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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