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Hatipoğlu E, Mikkelsen JH, Korsholm TL, Hvid M, Deleuran B, Dahl MLN. No evidence of increased anti-M3 muscarinic acetylcholine receptor autoantibodies in SSA-positive connective tissue disease patients. APMIS 2023; 131:552-555. [PMID: 37620885 DOI: 10.1111/apm.13349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023]
Abstract
Anti-muscarinic type 3 receptor autoantibodies (M3R) and anti-SSA antibodies are both related to salivary secretion. The presence of M3R antibodies in Sjögren's syndrome is previously demonstrated; nevertheless, the relationship between the anti-SSA antibodies and M3R fragment antibodies, namely the N terminal, first, second, and third extracellular loops, remains to be elucidated. In this study, we analyzed the antibodies against the M3R epitopes in healthy controls and anti-SSA antibody-positive connective tissue disease patients through ELISA method. Antibodies against the first, second, and third extracellular loop (M3R211-230 ) were not increased in anti-SSA positive patients compared to healthy controls. Indeed, antibodies against the N terminal (M3R1-33 ) were found to be high in healthy controls. High levels of M3R1-33 in healthy controls are a novel original finding; further research is needed for the clinical significance. There is no significant difference between SSA-positive patients and healthy controls in terms of autoantibodies against the remainder of the linear M3R fragments.
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Affiliation(s)
- Elif Hatipoğlu
- Faculty of Medicine, Hacettepe University, Ankara, Turkey
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Trine-Line Korsholm
- Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark
| | - Malene Hvid
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Bent Deleuran
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | - Marie Louise Naestholt Dahl
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
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2
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Zuo J, Williams AEG, Park YJ, Choi K, Chan AL, Reeves WH, Bubb MR, Lee YJ, Park K, Stewart CM, Cha S. Muscarinic type 3 receptor autoantibodies are associated with anti-SSA/Ro autoantibodies in Sjögren's syndrome. J Immunol Methods 2016; 437:28-36. [PMID: 27460476 DOI: 10.1016/j.jim.2016.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 01/05/2023]
Abstract
Anti-muscarinic type 3 receptor autoantibodies (anti-M3R) are reported as potential inhibitors of saliva secretion in Sjögren's syndrome (SjS). However, despite extensive efforts to establish an anti-M3R detection method, there is no clinical test available for these autoantibodies. The purpose of this study was to propose inclusion of anti-M3R testing for SjS diagnosis through investigation of their prevalence using a modified In-Cell Western (ICW) assay. A stable cell line expressing human M3R tagged with GFP (M3R-GFP) was established to screen unadsorbed and adsorbed plasma from primary SjS (n=24), rheumatoid arthritis (RA, n=18), systemic lupus erythematosus (SLE, n=18), and healthy controls (HC, n=23). Anti-M3R abundance was determined by screening for the intensity of human IgG interacting with M3R-GFP cells by ICW assay, as detected by an anti-human IgG IRDye800-conjugated secondary antibody and normalized to GFP. Method comparisons and receiver-operating-characteristic (ROC)-curve analyses were performed to evaluate the diagnostic value of our current approaches. Furthermore, clinical parameters of SjS were also analyzed in association with anti-M3R. Anti-M3R was significantly elevated in SjS plasma in comparison with HC, SLE, or RA (P<0.01). SjS anti-M3R intensities were greater than two-standard deviations above the HC mean for both unadsorbed (16/24, 66.67%) and adsorbed (18/24, 75%) plasma samples. Furthermore, anti-M3R was associated with anti-SjS-related-antigen A/Ro positivity (P=0.0353). Linear associations for anti-M3R intensity indicated positive associations with focus score (R(2)=0.7186, P<0.01) and negative associations with saliva flow rate (R(2)=0.3052, P<0.05). Our study strongly supports our rationale to propose inclusion of anti-M3R for further testing as a non-invasive serological marker for SjS diagnosis.
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Affiliation(s)
- Jian Zuo
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Adrienne E G Williams
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Yun-Jong Park
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Kevin Choi
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Annie L Chan
- Department of Rheumatology and Clinical Immunology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Westley H Reeves
- Department of Rheumatology and Clinical Immunology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Michael R Bubb
- Department of Rheumatology and Clinical Immunology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Yun Jong Lee
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyungpyo Park
- Department of Physiology, School of Dentistry, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Carol M Stewart
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Seunghee Cha
- Departments of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
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Reina S, Sterin-Borda L, Orman B, Borda E. Autoantibodies against Submandibular Gland Muscarinic Cholinoceptor Subtypes in Primary Sjögren Syndrome. EUR J INFLAMM 2016. [DOI: 10.1177/1721727x0500300305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sjögren Syndrome (SS) is a chronic autoimmune disease characterized by parasympathetic exocrine gland dysfunction. Here, the involvement of submandibular gland muscarinic acetylcholine receptor (mAChR) M4 subtype is proposed as an IgG target together with M1 and M3 mAChR subtypes. The Kd values were total membranes 0.20 ± 0.017 nM; acini membranes 0.33 ± 0.023 nM and duct membranes 0.22 ± 0.040 nM and Bmax values were total, 1038 ± 24, acini, 1359 ± 28 and ducts, 593 ± 30. The rank order of Bmax was: acini > total > ducts, indicating that acini express the highest number of binding sites. The specific mAChR antagonists (4-DAMP [M3], tropicamide [M4], pirenzepine [M1]) and the corresponding synthetic peptides impaired IgG-mAChR subtype interactions. The specificity of these reactions was assessed by the corresponding affinity-purified anti peptide antibodies recognizing M4, M3 and M1 mAChR. These data concerning autoantibodies contribute to explain the pathogenesis of SS and also represent a new clinical marker for SS diagnosis.
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Affiliation(s)
- S. Reina
- Pharmacology Unit, School of Dentistry, Buenos Aires University
| | - L. Sterin-Borda
- Pharmacology Unit, School of Dentistry, Buenos Aires University
- Argentine National Research Council (CONICET), Buenos Aires, Argentina
| | - B. Orman
- Pharmacology Unit, School of Dentistry, Buenos Aires University
| | - E. Borda
- Pharmacology Unit, School of Dentistry, Buenos Aires University
- Argentine National Research Council (CONICET), Buenos Aires, Argentina
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4
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A novel cell-based assay for inhibitory anti-muscarinic type 3 receptor antibodies in primary Sjögren’s syndrome. J Immunol Methods 2015; 427:117-21. [DOI: 10.1016/j.jim.2015.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/04/2015] [Accepted: 11/11/2015] [Indexed: 11/21/2022]
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Deng C, Hu C, Chen S, Li J, Wen X, Wu Z, Li Y, Zhang F, Li Y. Meta-analysis of anti-muscarinic receptor type 3 antibodies for the diagnosis of Sjögren syndrome. PLoS One 2015; 10:e0116744. [PMID: 25629973 PMCID: PMC4309563 DOI: 10.1371/journal.pone.0116744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/12/2014] [Indexed: 12/03/2022] Open
Abstract
Purpose To conduct a meta-analysis to evaluate the diagnostic value of anti-muscarinic receptor type 3 (M3R) antibodies in Sjögren syndrome (SS). Methods Two databases, PUBMED and the Cochrane Library, were systematically searched. Approximately 2,000 participants from several studies were included in this research. STATA 11.2 software and Meta-DiSc 1.4 was used to conduct the meta-analysis. Results Eleven studies were included in the meta-analysis. The pooled DOR was 13.00 (95% CI, 6.00–26.00). The sensitivity was 0.43 (95% CI, 0.28–0.58) and the specificity was 0.95 (95%CI, 0.91–0.97). The LR+ and LR- were 7.90 (95% CI, 4.70–13.40), 0.61 (95% CI, 0.46–0.79), respectively. The AUC was 0.89 (95% CI, 0.86–0.92). Conclusion The anti-M3R antibody had high specificity but relatively low sensitivity for the diagnosis of SS.
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Affiliation(s)
- Chuiwen Deng
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Chaojun Hu
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Si Chen
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Jing Li
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Xiaoting Wen
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Ziyan Wu
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Yuan Li
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Fengchun Zhang
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
| | - Yongzhe Li
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, China
- * E-mail:
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Reksten TR, Jonsson MV. Sjögren's syndrome: an update on epidemiology and current insights on pathophysiology. Oral Maxillofac Surg Clin North Am 2014; 26:1-12. [PMID: 24287189 DOI: 10.1016/j.coms.2013.09.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Primary Sjögren's syndrome (pSS) is an autoimmune chronic inflammatory disorder affecting 0.2% to 3.0% of the population, with a 9:1 female to male ratio. Features are oral and ocular dryness, local and systemic autoantibody production, and progressive focal mononuclear cell infiltration in the affected salivary and lacrimal glands. Lymphoma is the most severe complication of pSS, occurring in 4% to 5% of patients. Genetic studies identified an association with HLA and susceptibility genes in cytokine genes and genes involved in B-cell differentiation. Genetic variations may help explain why disease manifestations differ among patients and supports the hypothesis of certain distinct disease phenotypes.
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Affiliation(s)
- Tove R Reksten
- Broegelmann Research Laboratory, Department of Clinical Science, University of Bergen, The Laboratory Building, 5th Floor, Haukeland University Hospital, Bergen N-5021, Norway
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Preuss B, Tunaru S, Henes J, Offermanns S, Klein R. A novel luminescence-based method for the detection of functionally active antibodies to muscarinic acetylcholine receptors of the M3 type (mAchR3) in patients' sera. Clin Exp Immunol 2014; 177:179-89. [PMID: 24628494 DOI: 10.1111/cei.12324] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2014] [Indexed: 12/11/2022] Open
Abstract
In different bioassays, functional antibodies reacting with the human muscarinic acetylcholine receptor M3(mAchR3) have been detected in sera from patients with Sjögren's syndrome (SS), and there is strong evidence that those antibodies may have pathogenetic relevance. However, depending on the method of detection, their prevalence varied. Furthermore, those bioassays are difficult to standardize. We report on the development and optimization of a novel test system based on a luminometric method to determine downstream signalling of mAchR3 which produces specific and reproducible results. Chinese hamster ovarian (CHO) cells were transfected with plasmids encoding mAchR3 and a green fluorescence protein (GFP)/aequorin fusion protein. Incubation of cells with carbachol resulted in an increase in intracellular [Ca(2+)], which was detected by measuring light emission with a luminometer, and the effect of incubation with patients' immunoglobulins (Ig) was evaluated. Optimal cell density, Ig preparation and time of incubation with patients' sera were determined. Sera from patients with primary Sjögren's syndrome (pSS; n = 40), systemic sclerosis (SSc; n = 47), myasthenia gravis (MG; n = 133) and 50 blood donors were analysed. Optimal assay conditions were obtained with a cell density of 100 000 cells/ml, isolation of Ig by ammonium sulphate precipitation and short-term incubation. Based on this highly reliable assay, 50% of the pSS patients had antibodies which inhibited carbachol-induced activation of mAchR3; none of the SSc patients, 6% of the patients with MG and 12% of the blood donors had antibodies which reacted with the mAchR3. This method facilitates the determination of functional anti-mAchR3 antibodies in patients' sera, confirmed their high prevalence in pSS patients and may, therefore, help to analyse their pathogenetic and clinical relevance in more detail.
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Affiliation(s)
- B Preuss
- Department of Internal Medicine II, University of Tuebingen, Tuebingen, Germany
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8
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The role of M3 muscarinic acetylcholine receptor reactive T cells in Sjögren's syndrome: a critical review. J Autoimmun 2014; 51:44-50. [PMID: 24397962 DOI: 10.1016/j.jaut.2013.12.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 12/15/2013] [Indexed: 12/13/2022]
Abstract
CD4+ T cells constitute the majority of infiltrating cells in salivary glands and lachrymal glands of patients with Sjögren's syndrome (SS). The pathophysiology of SS involves T cell recognition of antigens through the T cell antigen receptor, which triggers cytokine production and chronic inflammation. The M3 muscarinic acetylcholine receptor (M3R) molecule is expressed in exocrine glands, such as salivary glands and lachrymal glands, and plays an important role in exocrine secretion. Previous studies indicated the presence of M3R reactive T cells in peripheral blood of 40% of patients with SS and autoantibodies against M3R in sera of 9-100% of the same patients. Thus, M3R is considered a candidate receptor for autoantigen recognition by T and B cells. The relationship between B cell epitopes and the function of anti-M3R antibodies has been reported, suggesting the pathogenic role of anti-M3R antibodies in xerostomia commonly seen in SS patients. We generated new experimental mouse model, M3R-induced sialadenitis (MIS), using Rag1(-/-) mice inoculated with splenocytes from M3R(-/-) mice immunized with M3R synthetic peptides. Mice with MIS developed severe SS-like sialadenitis. Cell transfer experiments using M3R(-/-)xIFNγ(-/-) mice and M3R(-/-)xIL-17(-/-) mice showed that IFNγ and IL-17 are key cytokines in the pathogenesis of sialadenitis. These findings indicate the crucial roles of M3R-reactive Th1 and Th17 cells in autoimmune sialadenitis, and suggest that these cells, in addition to anti-M3R antibodies, are potential targets in new treatments for SS.
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9
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Effects of muscarinic acetylcholine 3 receptor(208-227) peptide immunization on autoimmune response in nonobese diabetic mice. Clin Dev Immunol 2013; 2013:485213. [PMID: 24382973 PMCID: PMC3872023 DOI: 10.1155/2013/485213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 11/18/2013] [Accepted: 11/25/2013] [Indexed: 12/15/2022]
Abstract
The second extracellular loop (LFWQYFVGKRTVPPGECFIQFLSEPTITFGTAI, aa 205-237) of muscarinic acetylcholine 3 receptor (M3R) has been reported to be an epitope for autoantibodies generated during certain autoimmune disorders, including Sjögren's syndrome (SS). Autoantibodies against M3R(228-237) have been shown to interfere with the function of M3R. However, few studies have been performed on the M3R(205-227) peptide of the second extracellular loop. In the current study, we sought to investigate the effect of M3R(208-227) peptide immunization on autoimmune response in NOD/LtJ mice. We synthesized the M3R(208-227) peptide and immunized NOD/LtJ mice to investigate whether peptide-specific antibodies could be generated and whether immunization would lead to changes in autoimmune response in NOD/LtJ mice. Our results demonstrate that the secretions of Th-1, Th-2, and Th-17 cytokines are downregulated and lymphocytic infiltration is improved in the salivary glands and lacrimal glands following immunization with M3R(208-227) peptide in NOD/LtJ mice, suggesting that peptide immunotherapy using the M3R(208-227) peptide may represent a potential therapeutic alternative.
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Lee BH, Gauna AE, Perez G, Park YJ, Pauley KM, Kawai T, Cha S. Autoantibodies against muscarinic type 3 receptor in Sjögren's syndrome inhibit aquaporin 5 trafficking. PLoS One 2013; 8:e53113. [PMID: 23382834 PMCID: PMC3559734 DOI: 10.1371/journal.pone.0053113] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 11/23/2012] [Indexed: 11/19/2022] Open
Abstract
Sjögren's syndrome (SjS) is a chronic autoimmune disease that mainly targets the salivary and lacrimal glands. It has been controversial whether anti-muscarinic type 3 receptor (α-M3R) autoantibodies in patients with SjS inhibit intracellular trafficking of aquaporin-5 (AQP5), water transport protein, leading to secretory dysfunction. To address this issue, GFP-tagged human AQP5 was overexpressed in human salivary gland cells (HSG-hAQP5) and monitored AQP5 trafficking to the plasma membrane following carbachol (CCh, M3R agonist) stimulation. AQP5 trafficking was indeed mediated by M3R stimulation, shown in partial blockage of trafficking by M3R-antagonist 4-DAMP. HSG-hAQP5 pre-incubated with SjS plasma for 24 hours significantly reduced AQP5 trafficking with CCh, compared with HSG-hAQP5 pre-incubated with healthy control (HC) plasma. This inhibition was confirmed by monoclonal α-M3R antibody and pre-absorbed plasma. Interestingly, HSG-hAQP5 pre-incubated with SjS plasma showed no change in cell volume, compared to the cells incubated with HC plasma showing shrinkage by twenty percent after CCh-stimulation. Our findings clearly indicate that binding of anti-M3R autoantibodies to the receptor, which was verified by immunoprecipitation, suppresses AQP5 trafficking to the membrane and contribute to impaired fluid secretion in SjS. Our current study urges further investigations of clinical associations between SjS symptoms, such as degree of secretory dysfunction, cognitive impairment, and/or bladder irritation, and different profiles (titers, isotypes, and/or specificity) of anti-M3R autoantibodies in individuals with SjS.
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Affiliation(s)
- Byung Ha Lee
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Adrienne E. Gauna
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Geidys Perez
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Yun-jong Park
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Kaleb M. Pauley
- Department of Science and Mathematics, Cedarville University College of Arts and Sciences, Cedarville, Ohio, United States of America
| | - Toshihisa Kawai
- Department of Immunology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
| | - Seunghee Cha
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, Florida, United States of America
- * E-mail:
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11
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Deák M, Szvetnik A, Balog A, Sohár N, Varga R, Pokorny G, Tóth G, Kiss M, Kovács L. Neuroimmune interactions in Sjögren's syndrome: relationship of exocrine gland dysfunction with autoantibodies to muscarinic acetylcholine receptor-3 and mental health status parameters. Neuroimmunomodulation 2013; 20:79-86. [PMID: 23235351 DOI: 10.1159/000345177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 10/12/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Antimuscarinic acetylcholine receptor-3 (m3AChR) autoantibodies have been described in primary Sjögren's syndrome (pSS). The aim of this study was to compare various methods for their detection and to assess the contributions of anti-m3AChR and other immunological and psychosocial factors to the pathomechanism of secondary SS (sSS). METHODS Sixty-five rheumatoid arthritis (RA) patients, 103 systemic lupus erythematosus (SLE) patients, 76 pSS patients and 50 controls were compared. Three immunodominant epitopes of m3AChR were synthesized and used in ELISA. Two extracellular epitopes were also prepared in fusion with glutathione-S-transferase and one in conjugation with bovine serum albumin. Mental health status was assessed with the 36-item Short-Form Health Survey and Functional Assessment of Chronic Illness Therapy fatigue scale. Correlations were evaluated between glandular function and anti-m3AChR positivities and specificities, features of SLE and RA, and mental health parameters. RESULTS Fourteen RA and 27 SLE patients had sSS. The autoantibody levels to all epitopes of m3AChR were significantly higher in pSS and SLE patients than in the controls. The fusion protein forms discriminated RA from pSS and SLE; furthermore, the YNIP fusion protein also distinguished pSS from SLE. The prevalence and the mean levels of all autoantibodies did not differ statistically between sicca and non-sicca SLE or RA patients. Glandular dysfunction correlated with higher age in SLE and RA and an impaired health-related quality of life in SLE. CONCLUSIONS The second and third extracellular loops of m3AChR are antigenic in pSS. Immunoassays with antigens as fusion peptides demonstrate the best performance. Sicca SLE patients have worse mental health status. Anti-m3AChR antibodies represent a peculiar example of neuroimmune interactions.
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Affiliation(s)
- Magdolna Deák
- Department of Rheumatology, Faculty of Medicine, Albert Szent-Györgyi Health Centre, University of Szeged, Szeged, Hungary.
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Sumida T, Tsuboi H, Iizuka M, Asashima H, Matsumoto I. Anti-M3 muscarinic acetylcholine receptor antibodies in patients with Sjögren's syndrome. Mod Rheumatol 2012; 23:841-5. [PMID: 23135882 DOI: 10.1007/s10165-012-0788-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/17/2012] [Indexed: 10/27/2022]
Abstract
Sjögren's syndrome (SS) is an autoimmune disease that affects exocrine glands including salivary and lacrimal glands. Recently, autoantibodies against muscarinic acetylcholine receptor M3 (M3R) have been detected in serum from 9 to 100 % of patients with SS in addition to anti-SS-A and anti-SS-B antibodies. These observations suggest the possibility that anti-M3R antibodies could serve as a new diagnostic test in patients with SS. Some anti-M3R antibodies are directly responsible for salivary underproduction in patients with SS. Thus, strategies designed to eliminate such pathogenic antibodies could help cure SS sufferers. In this review, we summarize the current state of knowledge of anti-M3R autoantibodies in patients with SS and the correlation between B cell epitopes and the function of anti-M3R antibodies.
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Affiliation(s)
- Takayuki Sumida
- Department of Internal Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan,
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Pavlakis P, Alexopoulos H, Kosmidis M, Mamali I, Moutsopoulos H, Tzioufas A, Dalakas M. Peripheral neuropathies in Sjögren’s syndrome: A critical update on clinical features and pathogenetic mechanisms. J Autoimmun 2012; 39:27-33. [DOI: 10.1016/j.jaut.2012.01.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/07/2012] [Indexed: 10/14/2022]
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14
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Bournia VK, Vlachoyiannopoulos PG. Subgroups of Sjögren syndrome patients according to serological profiles. J Autoimmun 2012; 39:15-26. [PMID: 22575069 DOI: 10.1016/j.jaut.2012.03.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Sjögren Syndrome (SS) is a systemic, autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands. Different clinical associations have been described for each of the diverse autoantibodies found in SS patients. Antibodies directed against the Ro/La ribonucleoprotein complexes have been correlated with younger age, more severe dysfunction of the exocrine glands and a higher prevalence of extraglandular manifestations. Anti-nuclear antibodies and rheumatoid factors have been associated to extraglandular manifestations and an active immunological profile, while cryoglobulins are markers of more severe disease and correlate to lymphoma development and death. Antibodies to cyclic citrullinated peptides are scarce in SS and have been linked in some cases to the development of non-erosive arthritis. Furthermore, the presence of anti-mitochondrial antibodies and anti-smooth muscle antibodies in the sera of primary SS patients is considered indicative of primary biliary cirrhosis and autoimmune hepatitis, respectively. In addition, anti-centromere antibodies have been associated with a clinical phenotype intermediate between primary SS and systemic sclerosis, while antibodies against carbonic anhydrase have been related to renal tubular acidosis. Finally, an association of anti-muscarinic antibodies with cytopenias and a higher disease activity has also been described in primary SS. In conclusion, although not all of the above mentioned antibodies are useful for predicting distinct patient subgroups in SS, knowledge of the clinical associations of the different autoantibody specificities encountered in SS can advance our understanding of the disease and improve patient management.
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Affiliation(s)
- Vasiliki-Kalliopi Bournia
- Department of Pathophysiology, Medical School, University of Athens, Mikras Asias 75, 115 27 Athens, Greece
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15
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Jin M, Hwang SM, Davies AJ, Shin Y, Bae JS, Lee JH, Lee EB, Song YW, Park K. Autoantibodies in primary Sjögren's syndrome patients induce internalization of muscarinic type 3 receptors. Biochim Biophys Acta Mol Basis Dis 2011; 1822:161-7. [PMID: 22137887 DOI: 10.1016/j.bbadis.2011.11.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/10/2011] [Accepted: 11/14/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by lymphocyte infiltration into the salivary and lachrymal glands, leading to dry mouth and eyes. The presence of functional autoantibodies against muscarinic type 3 receptor (M3R) has been reported in pSS patients. However, the pathological role of anti-M3R autoantibodies in pSS salivary dysfunction remains controversial. METHODS Purified IgGs were obtained from normal (control) and primary SS patients' sera (pSS IgG). Internalization of M3R and clathrin was analyzed by biochemical assay and immunofluorescence confocal microscopy using human submandibular gland (hSMG) cells. Cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) was measured by microspectrofluorimetry. RESULTS Incubation of hSMG cells with pSS IgG (1mg/ml) significantly decreased M3R expression levels at the membrane. Carbachol-induced [Ca(2+)](i) transients (CICTs) in these cells were also inhibited by pSS IgG. In contrast to pSS IgG, control IgG had no effect on both the M3R expression level and CICTs. We found that binding of pSS IgG to M3R induces phosphorylation of the receptor, and that the pSS IgG-induced M3R internalization is prevented by the lysosomal inhibitor, chloroquine. In addition, pSS IgG decreased membrane clathrin expression, which was inhibited by atropine. Our immunofluorescence study further confirmed that pSS IgG induces a co-localization of M3R with clathrin and subsequent internalization of M3R. CONCLUSION pSS IgG induces internalization of M3R partly through a clathrin-mediated pathway. The results suggest M3R internalization as a potential mechanism to explain the exocrinopathy seen in pSS patients.
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Affiliation(s)
- Meihong Jin
- Department of Physiology, College of Medicine, Seoul National University and Dental Research Institute, Seoul 110-749, Republic of Korea
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Passafaro D, Reina S, Sterin-Borda L, Borda E. Cholinergic autoantibodies from primary Sjögren's syndrome modulate submandibular gland Na+/K+-ATPase activity via prostaglandin E2 and cyclic AMP. Eur J Oral Sci 2010; 118:131-8. [PMID: 20487001 DOI: 10.1111/j.1600-0722.2010.00716.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate that patients with primary Sjögren's syndrome (pSS) produce functional IgG autoantibodies that interact with the glandular M(3) muscarinic acetylcholine receptors (mAChRs). These autoantibodies act as a partial muscarinic agonist, increasing prostaglandin E(2) (PGE(2)) and cyclic AMP production through modifying Na(+)/K(+)-ATPase activity, but also interfere with the secretory effect of the parasympathetic neurotransmitter. The IgG from patients with pSS has two effects on the submandibular gland. On the one hand, it may act as an inducer of the proinflammatory molecule (PGE(2)) that, in turn, inhibits Na(+)/K(+)-ATPase activity. On the other hand, it plays a role in the pathogenesis of dry mouth, abolishing the Na(+)/K(+)-ATPase inhibition and the net K(+) efflux stimulation of the salivary gland in response to the authentic agonist pilocarpine, decreasing salivary fluid production.
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Affiliation(s)
- Daniela Passafaro
- Pharmacology Unit, School of Dentistry, Buenos Aires University, Buenos Aires, Argentina
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Tsuboi H, Matsuo N, Iizuka M, Nakamura Y, Matsumoto I, Sumida T. [Analysis of epitopes and function of anti-M3 muscarinic acetylcholine receptor antibodies in patients with Sjögren's syndrome]. NIHON RINSHO MEN'EKI GAKKAI KAISHI = JAPANESE JOURNAL OF CLINICAL IMMUNOLOGY 2010; 33:222-8. [PMID: 20818151 DOI: 10.2177/jsci.33.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sjögren's syndrome (SS) is an autoimmune disease that affects exocrine glands including salivary and lacrimal glands. It is characterized by lymphocytic infiltration into exocrine glands, leading to dry mouth and eyes. A number of auto-antibodies, such as anti-SS-A and SS-B antibodies, are detected in patients with SS. However, no SS-specific pathologic auto-antibodies have yet been found in this condition. M3 muscarinic acetylcholine receptor (M3R) plays a crucial role in the secretion of saliva from salivary glands. It is reported that some patients with SS carried inhibitory auto-antibodies against M3R. To clarify the epitopes and function of anti-M3R antibodies in SS, we examined antibodies to the extracellular domains (N terminal region, the first, second, and third extracellular loop) of M3R by ELISA using synthesized peptide antigens encoding these domains in 42 SS and 42 healthy controls (HC). Titers and positivity of anti-M3R antibodies to every extracellular domain of M3R were significantly higher in SS than in HC. For functional analysis, human salivary gland (HSG) cells were pre-cultured with IgG from anti-M3R antibodies positive SS, negative SS, and HC. HSG cells were stimulated with cevimeline hydrochloride and intracellular calcium concentration ([Ca(2+)](i)) was measured. IgG from anti-M3R antibodies to the second loop positive SS inhibited the increase of [Ca(2+)](i), but IgG from antibodies to the N terminal or the first loop positive SS enhanced it, while IgG from antibodies to the third loop positive SS showed no effect on [Ca(2+)](i) as well as IgG from anti-M3R antibodies negative SS and HC. These findings indicated the presence of several B cell epitopes on M3R in SS and effect of anti-M3R antibodies on the salivary secretion might differ with these epitopes.
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Affiliation(s)
- Hiroto Tsuboi
- Division of Clinical Immunology, Doctoral Program in Clinical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba
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18
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Tsuboi H, Matsumoto I, Wakamatsu E, Nakamura Y, Iizuka M, Hayashi T, Goto D, Ito S, Sumida T. New epitopes and function of anti-M3 muscarinic acetylcholine receptor antibodies in patients with Sjögren's syndrome. Clin Exp Immunol 2010; 162:53-61. [PMID: 20731676 DOI: 10.1111/j.1365-2249.2010.04188.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
M3 muscarinic acetylcholine receptor (M3R) plays a crucial role in the secretion of saliva from salivary glands. It is reported that some patients with Sjögren's syndrome (SS) carried inhibitory autoantibodies against M3R. The purpose of this study is to clarify the epitopes and function of anti-M3R antibodies in SS. We synthesized peptides encoding the extracellular domains of human-M3R including the N-terminal region and the first, second and third extracellular loops. Antibodies against these regions were examined by enzyme-linked immunosorbent assay in sera from 42 SS and 42 healthy controls. For functional analysis, human salivary gland (HSG) cells were preincubated with immunoglobulin G (IgG) separated from sera of anti-M3R antibody-positive SS, -negative SS and controls for 12 h. After loading with Fluo-3, HSG cells were stimulated with cevimeline hydrochloride, and intracellular Ca(2+) concentrations [(Ca(2+) )i] were measured. Antibodies to the N-terminal, first, second and third loops were detected in 42·9% (18 of 42), 47·6% (20 of 42), 54·8% (23 of 42) and 45·2% (19 of 42) of SS, while in 4·8% (two of 42), 7·1% (three of 42), 2·4% (one of 42) and 2·4% (one of 42) of controls, respectively. Antibodies to the second loop positive SS-IgG inhibited the increase of (Ca(2+) )i induced by cevimeline hydrochloride. Antibodies to the N-terminal positive SS-IgG and antibodies to the first loop positive SS-IgG enhanced it, while antibodies to the third loop positive SS-IgG showed no effect on (Ca(2+) )i as well as anti-M3R antibody-negative SS-IgG. Our results indicated the presence of several B cell epitopes on M3R in SS. The influence of anti-M3R antibodies on salivary secretion might differ based on these epitopes.
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Affiliation(s)
- H Tsuboi
- Division of Clinical Immunology, Doctoral Program in Clinical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
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Singh J, Mehendiratta V, Del Galdo F, Jimenez SA, Cohen S, DiMarino AJ, Rattan S. Immunoglobulins from scleroderma patients inhibit the muscarinic receptor activation in internal anal sphincter smooth muscle cells. Am J Physiol Gastrointest Liver Physiol 2009; 297:G1206-13. [PMID: 19779020 PMCID: PMC2850093 DOI: 10.1152/ajpgi.00286.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Systemic sclerosis (SSc) IgGs affecting the M(3)-muscarinic receptor (M(3)-R) have been proposed to be responsible for the gastrointestinal (GI) dysmotility in this disease. However, the effect of SSc IgGs on smooth muscle cell (SMC) function has not been studied. We determined the effect of SSc IgGs on the muscarinic receptor activation by bethanechol (BeCh; methyl derivate of carbachol) in SMC and smooth muscle strips from rat internal anal sphincter. IgGs were purified from GI-symptomatic SSc patients and normal volunteers, with protein G-Sepharose columns. SMC lengths were determined via computerized digital micrometry. The presence of M(3)-R and IgG-M(3)-R complex was determined by Western blot. IgGs from SSc patients but not from normal volunteers caused significant and concentration-dependent inhibition of BeCh response (P < 0.05). The maximal shortening of 22.2 +/- 1.2% caused by 10(-4) M BeCh was significantly attenuated to 8.3 +/- 1.2% by 1 mg/ml of SSc IgGs (P < 0.05). Experiments performed in smooth muscle strips revealed a similar effect of SSc IgG that was fully reversible. In contrast to the effect on BeCh, the SSc IgGs caused no significant effect (P > 0.05) on K(+) depolarization and alpha(1)-adrenoceptor activation by phenylephrine. Western blot studies revealed the specific presence of SSc IgG-M(3)-R complex. SSc IgGs attenuated M(3)-R activation, which was reversible with antibody removal. These data suggest that SSc GI dysmotility may be caused by autoantibodies that inhibit the muscarinic neurotransmission. Future treatment of SSc patients may be directed at the removal or neutralization of these antibodies.
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Affiliation(s)
- Jagmohan Singh
- 1Department of Medicine, Division of Gastroenterology and Hepatology, and
| | | | - Francesco Del Galdo
- 2Scleroderma Center and Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sergio A. Jimenez
- 2Scleroderma Center and Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
| | | | | | - Satish Rattan
- 1Department of Medicine, Division of Gastroenterology and Hepatology, and
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Kovács L, Fehér E, Bodnár I, Marczinovits I, Nagy GM, Somos J, Boda V. Demonstration of autoantibody binding to muscarinic acetylcholine receptors in the salivary gland in primary Sjögren's syndrome. Clin Immunol 2008; 128:269-76. [DOI: 10.1016/j.clim.2008.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 01/31/2008] [Accepted: 04/05/2008] [Indexed: 11/24/2022]
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Evidence that anti-muscarinic antibodies in Sjögren's syndrome recognise both M3R and M1R. Biologicals 2008; 36:213-22. [PMID: 18249005 DOI: 10.1016/j.biologicals.2007.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Revised: 11/12/2007] [Accepted: 11/14/2007] [Indexed: 01/31/2023] Open
Abstract
Inhibitory anti-muscarinic receptor type 3 (M3R) antibodies may contribute to the pathogenesis of Sjögren's syndrome (SS), and putative anti-M3R blocking antibodies in intravenous immunoglobulin (IVIg) have been suggested as a rationale for treatment with IVIg. We investigated the presence of subtype-specific anti-MR autoantibodies in healthy donor and SS sera using MR-transfected whole-cell binding assays as well as M1R and M3R peptide ELISAs. Control antibodies against the second extracellular loop of the M3R, a suggested target epitope, were induced in rabbits and found to be cross-reactive on the peptides M3R and M1R. The rabbit antibodies had neither an agonistic nor an antagonistic effect on M3R-dependent ERK1/2 signalling. Only one primary SS (out of 5 primary SS, 2 secondary SS and 5 control sera) reacted strongly with M3R transfected cells. The same SS serum also reacted strongly with M1R and M2R transfectants, as well as M1R and two different M3R peptides. Strong binding to M1R and low-level activities against M3R peptides were observed both in SS and control sera. IVIg showed a strong reactivity against all three peptides, especially M1R. Our results indicate that certain SS individuals may have antibodies against M1R, M2R and M3R. Our results also suggest that neither the linear M3R peptide nor M3R transfectants represent suitable tools for discrimination of pathogenic from natural autoantibodies in SS.
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Reina S, Orman B, Anaya JM, Sterin-Borda L, Borda E. Cholinoreceptor autoantibodies in Sjögren syndrome. J Dent Res 2007; 86:832-6. [PMID: 17720850 DOI: 10.1177/154405910708600905] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Previous studies have demonstrated that antibodies against cholinoreceptors of exocrine glands correlate with dry mouth in persons with primary Sjögren syndrome (pSS). The aim of the present investigation was to establish if serum IgG antibodies (pSS IgG) were able to interact with cholinoreceptors in rat submandibular gland-dependent stimulation of cyclooxygenase 2 (COX-2) mRNA expression and PGE(2) production. Our findings indicated that pSS IgG-stimulating M(3), M(4), and M(1) cholinoreceptors exerted an increase in COX-2 mRNA without affecting COX-1 mRNA expression and increased PGE(2) production. Inhibitors of phospholipase A(2), COX- s, L-type calcium channel currents, and Ca(2+)-ATPase from sarcoplasmic reticulum prevented the pSS IgG effect on PGE(2) production. An ionophore of calcium mimicked pSS IgG action, suggesting a crucial role of calcium homeostasis in the cholinoreceptor-stimulated increase in PGE(2) production. Moreover, the amounts of PGE(2) in saliva and in sera from persons with pSS were significantly higher than in pre- or post-menopausal women. These findings illustrate the importance of autoantibodies to cholinoreceptors in the generation of chronic inflammation of target tissues in SS.
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Affiliation(s)
- S Reina
- Pharmacology Unit, School of Dentistry, University of Buenos Aires, 1122 AAH, Buenos Aires, Argentina
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Dawson LJ, Stanbury J, Venn N, Hasdimir B, Rogers SN, Smith PM. Antimuscarinic antibodies in primary Sjögren's syndrome reversibly inhibit the mechanism of fluid secretion by human submandibular salivary acinar cells. ACTA ACUST UNITED AC 2006; 54:1165-73. [PMID: 16572451 DOI: 10.1002/art.21764] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Sjögren's syndrome (SS) is an autoimmune condition affecting salivary glands, for which a clearly defined pathogenic autoantibody has yet to be identified. Autoantibodies that bind to the muscarinic M3 receptors (M3R), which regulate fluid secretion in salivary glands, have been proposed in this context. However, there are no previous data that directly show antisecretory activity. This study was undertaken to investigate and characterize the antisecretory activity of anti-M3R. METHODS Microfluorimetric Ca2+ imaging and patch clamp electrophysiologic techniques were used to measure the secretagogue-evoked increase in [Ca2+]i and consequent activation of Ca2+-dependent ion channels in individual mouse and human submandibular acinar cells. Together, these techniques form a sensitive bioassay that was used to determine whether IgG isolated from patients with primary SS and from control subjects has antisecretory activity. RESULTS IgG (2 mg/ml) from patients with primary SS reduced the carbachol-evoked increase in [Ca2+]i in both mouse and human acinar cells by approximately 50%. IgG from control subjects had no effect on the Ca2+ signal. Furthermore, the inhibitory action of primary SS patient IgG on the Ca2+ signal was acutely reversible. We repeated our observations using rabbit serum containing antibodies raised against the second extracellular loop of M3R and found an identical pattern of acutely reversible inhibition. Anti-M3R-positive serum had no effect on Ca2+-dependent ion channel activation evoked by the direct intracellular infusion of inositol 1,4,5-triphosphate. CONCLUSION These observations show for the first time that IgG from patients with primary SS contains autoantibodies capable of damaging saliva production and contributing to xerostomia. The unusual but not unprecedented acute reversibility of the effects of anti-M3 autoantibodies is the subject of further research.
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Affiliation(s)
- L J Dawson
- The University of Liverpool, and Aintree Hospitals, Liverpool, UK.
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Dawson LJ, Fox PC, Smith PM. Sjögrens syndrome—the non-apoptotic model of glandular hypofunction. Rheumatology (Oxford) 2006; 45:792-8. [PMID: 16595520 DOI: 10.1093/rheumatology/kel067] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- L J Dawson
- Oral Surgery, University of Liverpool Dental School, Room 1.10, Edwards Building, Daulby Street, Liverpool L69 3GN, UK.
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Kovács L, Marczinovits I, György A, Tóth GK, Dorgai L, Pál J, Molnár J, Pokorny G. Clinical associations of autoantibodies to human muscarinic acetylcholine receptor 3213–228 in primary Sjögren's syndrome. Rheumatology (Oxford) 2005; 44:1021-5. [PMID: 15888503 DOI: 10.1093/rheumatology/keh672] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES The authors have previously identified a peptide of the human muscarinic acetylcholine receptor-3 (m3AChR) as a suitable antigen for the immunodetection of antimuscarinic acetylcholine receptor autoantibodies in primary Sjögren's syndrome (pSS). The aim of this study was to assess the clinical correlations and disease specificity of these antibodies. METHODS Seventy-three pSS, 40 rheumatoid arthritis (RA), 19 systemic lupus erythematosus (SLE), 14 secondary Sjögren's syndrome (sSS) patients, 22 subjects in whom pSS was suspected but in whom the diagnosis not could eventually be established (suspSS) and 40 healthy subjects were investigated. An enzyme-linked immunosorbent assay system developed by the authors using a 16-mer peptide of the m3AChR (m3AChR(213-228)) in a recombinant fusion peptide form was used as the antigen. RESULTS Anti-m3AChR(213-228) antibody positivity was observed in 66 (90%) of the pSS patients. The antibody levels correlated positively with the number of extraglandular organ manifestations. Both the mean antibody levels and the occurrence of anti-m3AChR(213-228) positivity were significantly higher in pSS than in the comparison groups. The test discriminated the pSS patients from the various comparison groups with specificities of 65, 68, 71 and 50% for RA, SLE, sSS and suspSS, respectively. CONCLUSIONS The presence of m3AChR(213-228) antibodies is a common feature in pSS. Although it is significantly more common in pSS than in the comparison groups, anti-m3AChR(213-228) positivity is not exclusive to pSS.
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Affiliation(s)
- L Kovács
- Department of Rheumatology, University of Szeged, Pécs, Hungary.
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