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Yamada Y. Histogenetic and disease-relevant phenotypes in thymic epithelial tumors (TETs): The potential significance for future TET classification. Pathol Int 2023; 73:265-280. [PMID: 37278579 DOI: 10.1111/pin.13343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/18/2023] [Indexed: 06/07/2023]
Abstract
Thymic epithelial tumors (TETs) encompass morphologically various subtypes. Thus, it would be meaningful to explore the expression phenotypes that delineate each TET subtype or overarching multiple subtypes. If these profiles are related to thymic physiology, they will improve our biological understanding of TETs and may contribute to the establishment of a more rational TET classification. Against this background, pathologists have attempted to identify histogenetic features in TETs for a long time. As part of this work, our group has reported several TET expression profiles that are histotype-dependent and related to the nature of thymic epithelial cells (TECs). For example, we found that beta5t, a constituent of thymoproteasome unique to cortical TECs, is expressed mainly in type B thymomas, for which the nomenclature of cortical thymoma was once considered. Another example is the discovery that most thymic carcinomas, especially thymic squamous cell carcinomas, exhibit expression profiles similar to tuft cells, a recently discovered special type of medullary TEC. This review outlines the currently reported histogenetic phenotypes of TETs, including those related to thymoma-associated myasthenia gravis, summarizes their genetic signatures, and provides a perspective for the future direction of TET classification.
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Affiliation(s)
- Yosuke Yamada
- Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan
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Jiao P, Tian WX, Wu FJ, Liu YX, Wu JY, Sun YG, Yu HB, Huang C, Wu QJ, Ma C, Li DH, Tong HF, Li J. Postoperative clinical outcomes of patients with thymic epithelial tumors after over-3-year follow-up at a single-center. J Cardiothorac Surg 2023; 18:77. [PMID: 36810094 PMCID: PMC9942311 DOI: 10.1186/s13019-023-02169-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/27/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND To evaluate postoperative clinical outcomes and analyze influencing factors for patients with thymic epithelial tumors over 3 years after operation. METHODS Patients with thymic epithelial tumors (TETs) who underwent surgical treatment in the Department of Thoracic Surgery at Beijing Hospital from January 2011 to May 2019 were retrospectively enrolled in the study. Basic patient information, clinical, pathological, and perioperative data were collected. Patients were followed up by telephone interviews and outpatient records. Statistical analyses were performed using SPSS version 26.0. RESULTS A total of 242 patients (129 men, 113 women) with TETs were included in this study, of which 150 patients (62.0%) were combined with myasthenia gravis (MG) and 92 patients (38.0%) were not. 216 patients were successfully followed up and their complete information was available. The median follow-up period was 70.5 months (range, 2-137 months). The 3-year overall survival (OS) rate of the whole group was 93.9%, and the 5-year OS rate was 91.1%. The 3-year relapse-free survival (RFS) rate of the whole group was 92.2%, and the 5-year relapse-free survival rate was 89.8%. Multivariable COX regression analysis indicated that recurrence of thymoma was an independent risk factor for OS. Younger age, Masaoka-Koga stage III + IV, and TNM stage III + IV were independent risk factors for RFS. Multivariable COX regression analysis indicated that Masaoka-Koga staging III + IV, WHO type B + C were independent risk factors for postoperative improvement of MG. For patients with MG, the postoperative complete stable remission (CSR) rate was 30.5%. And the result of multivariable COX regression analysis showed that thymoma patients with MG with Osserman staging IIA + IIB + III + IV were not prone to achieving CSR. Compared with patients without MG, MG was more likely to develop in patients with WHO classification type B, and patients with myasthenia gravis were younger, with longer operative duration, and more likely to develop perioperative complications. CONCLUSIONS The 5-year overall survival rate of patients with TETs was 91.1% in this study. Younger age and advanced stage were independent risk factors for RFS of patients with TETs, and recurrence of thymoma were independent risk factors for OS. In patients with MG, WHO classification type B and advanced stage were independent predictors of poor outcomes of MG treatment after thymectomy.
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Affiliation(s)
- Peng Jiao
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Wen-Xin Tian
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Fan-Juan Wu
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Yu-Xing Liu
- grid.11135.370000 0001 2256 9319Peking University Health Science Center, Beijing, People’s Republic of China
| | - Jiang-Yu Wu
- grid.11135.370000 0001 2256 9319Peking University Health Science Center, Beijing, People’s Republic of China
| | - Yao-Guang Sun
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Han-Bo Yu
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Chuan Huang
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Qing-Jun Wu
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Chao Ma
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Dong-Hang Li
- grid.506261.60000 0001 0706 7839Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People’s Republic of China
| | - Hong-Feng Tong
- Department of Thoracic Surgery, Beijing Hospital, National Center of Gerontology; Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
| | - Jun Li
- Department of Thoracic Surgery, Provincial Hospital Affiliated to Shandong First Medical University, No. 324, Jing 5 Wei 7 Road, Jinan, 250021, Shandong, People's Republic of China.
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Point Counter-Point: Thymectomy in Ocular Myasthenia Gravis. J Neuroophthalmol 2022; 42:541-546. [PMID: 36394968 DOI: 10.1097/wno.0000000000001748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Yamada Y, Weis CA, Thelen J, Sticht C, Schalke B, Ströbel P, Marx A. Thymoma Associated Myasthenia Gravis (TAMG): Differential Expression of Functional Pathways in Relation to MG Status in Different Thymoma Histotypes. Front Immunol 2020; 11:664. [PMID: 32373124 PMCID: PMC7176899 DOI: 10.3389/fimmu.2020.00664] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/23/2020] [Indexed: 01/29/2023] Open
Abstract
A unique feature of thymomas is their unrivaled frequency of associated myasthenia gravis (MG). Previous studies reported that MG+ thymomas contain a larger number of mature “pre-emigrant” CD4+ T cells than MG- thymomas and that most thymomas do not contain AIRE expressing cells irrespective of MG status. These findings suggest that CD4+ T cells that mature inside the abnormal microenvironment of thymomas and egress to the blood are critical to the development of thymoma-associated MG (TAMG) irrespective of thymoma histotype. However, underlying mechanisms have remained enigmatic. To get hints to mechanisms underlying TAMG, we pursue three hypotheses: (i) Functional pathways with metabolic and immunological relevance might be differentially expressed in TAMG(+) compared to TAMG(-) thymomas; (ii) differentially enriched pathways might be more evident in immature lymphocyte-poor (i.e., tumor cell/stroma-rich) thymoma subgroups; and (iii) mechanisms leading to TAMG might be different among thymoma histological subtypes. To test these hypotheses, we compared the expression of functional pathways with potential immunological relevance (N = 380) in relation to MG status separately in type AB and B2 thymomas and immature lymphocyte-rich and lymphocyte-poor subgroups of these thymoma types using the TCGA data set. We found that <10% of the investigated pathways were differentially upregulated or downregulated in MG+ compared to MG- thymomas with significant differences between AB and B2 thymomas. The differences were particularly evident, when epithelial cell/stroma-rich subsets of type AB and B2 thymomas were analyzed. Unexpectedly, some MG-associated pathways that were significantly upregulated in AB thymomas were significantly downregulated in B2 thymomas, as exemplified by the oxidative phosphorylation pathway. Conversely, the MG-associated pathway related to macrophage polarization was downregulated in MG+ AB thymoma and upregulated in MG+ B2 thymoma. We conclude that functional pathways are significantly associated with TAMG, and that some mechanisms leading to TAMG might be different among thymoma histological subtypes. Functions related to metabolisms, vascular and macrophage biology are promising new candidate mechanisms potentially involved in the pathogenesis of TAMG. More generally, the results imply that future studies addressing pathomechanisms of TAMG should take the histotype and abundance of tumor cells and non-neoplastic stromal components of thymomas into account.
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Affiliation(s)
- Yosuke Yamada
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany
| | - Cleo-Aron Weis
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany
| | - Julian Thelen
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany
| | - Carsten Sticht
- Medical Faculty Mannheim, Medical Research Center, Heidelberg University, Mannheim, Germany
| | - Berthold Schalke
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Philipp Ströbel
- Institute of Pathology, University Medical Center Göttingen, University of Göttingen, Göttingen, Germany
| | - Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany
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Radovich M, Pickering CR, Felau I, Ha G, Zhang H, Jo H, Hoadley KA, Anur P, Zhang J, McLellan M, Bowlby R, Matthew T, Danilova L, Hegde AM, Kim J, Leiserson MDM, Sethi G, Lu C, Ryan M, Su X, Cherniack AD, Robertson G, Akbani R, Spellman P, Weinstein JN, Hayes DN, Raphael B, Lichtenberg T, Leraas K, Zenklusen JC, Fujimoto J, Scapulatempo-Neto C, Moreira AL, Hwang D, Huang J, Marino M, Korst R, Giaccone G, Gokmen-Polar Y, Badve S, Rajan A, Ströbel P, Girard N, Tsao MS, Marx A, Tsao AS, Loehrer PJ. The Integrated Genomic Landscape of Thymic Epithelial Tumors. Cancer Cell 2018; 33:244-258.e10. [PMID: 29438696 PMCID: PMC5994906 DOI: 10.1016/j.ccell.2018.01.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/15/2017] [Accepted: 01/09/2018] [Indexed: 12/31/2022]
Abstract
Thymic epithelial tumors (TETs) are one of the rarest adult malignancies. Among TETs, thymoma is the most predominant, characterized by a unique association with autoimmune diseases, followed by thymic carcinoma, which is less common but more clinically aggressive. Using multi-platform omics analyses on 117 TETs, we define four subtypes of these tumors defined by genomic hallmarks and an association with survival and World Health Organization histological subtype. We further demonstrate a marked prevalence of a thymoma-specific mutated oncogene, GTF2I, and explore its biological effects on multi-platform analysis. We further observe enrichment of mutations in HRAS, NRAS, and TP53. Last, we identify a molecular link between thymoma and the autoimmune disease myasthenia gravis, characterized by tumoral overexpression of muscle autoantigens, and increased aneuploidy.
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Affiliation(s)
- Milan Radovich
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | | | - Ina Felau
- National Cancer Institute, Bethesda, MD 20892, USA
| | - Gavin Ha
- Broad Institute, Cambridge, MA 02142, USA
| | | | - Heejoon Jo
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Katherine A Hoadley
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pavana Anur
- Oregon Health & Science University, Portland, OR 97239, USA
| | - Jiexin Zhang
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mike McLellan
- McDonnell Genome Institute at Washington University, St. Louis, MO 63108, USA
| | - Reanne Bowlby
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, BC V5Z 4S6, Canada
| | - Thomas Matthew
- University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | | | | | - Jaegil Kim
- Broad Institute, Cambridge, MA 02142, USA
| | - Mark D M Leiserson
- Department of Computer Science & Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
| | - Geetika Sethi
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Charles Lu
- McDonnell Genome Institute at Washington University, St. Louis, MO 63108, USA
| | - Michael Ryan
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaoping Su
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | | | - Gordon Robertson
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, BC V5Z 4S6, Canada
| | - Rehan Akbani
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Paul Spellman
- Oregon Health & Science University, Portland, OR 97239, USA
| | | | - D Neil Hayes
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ben Raphael
- Department of Computer Science & Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
| | | | | | | | | | | | | | - David Hwang
- University Health Network, Toronto, ON M5G 2C4, Canada
| | - James Huang
- Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mirella Marino
- Department of Pathology, Regina Elena National Cancer Institute, Rome 00144, Italy
| | | | | | - Yesim Gokmen-Polar
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Sunil Badve
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Arun Rajan
- National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Nicolas Girard
- Institute of Oncology, Cardiobiotec, Hospices Civils de Lyon, Lyon 69002, France
| | - Ming S Tsao
- Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Alexander Marx
- University Medical Centre Mannheim, University of Heidelberg, Mannheim 68167, Germany
| | - Anne S Tsao
- MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Patrick J Loehrer
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA.
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Wang Z, Yan Y. Immunopathogenesis in Myasthenia Gravis and Neuromyelitis Optica. Front Immunol 2017; 8:1785. [PMID: 29312313 PMCID: PMC5732908 DOI: 10.3389/fimmu.2017.01785] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/29/2017] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) and neuromyelitis optica (NMO) are autoimmune channelopathies of the peripheral neuromuscular junction (NMJ) and central nervous system (CNS) that are mainly mediated by humoral immunity against the acetylcholine receptor (AChR) and aquaporin-4 (AQP4), respectively. The diseases share some common features, including genetic predispositions, environmental factors, the breakdown of tolerance, the collaboration of T cells and B cells, imbalances in T helper 1 (Th1)/Th2/Th17/regulatory T cells, aberrant cytokine and antibody secretion, and complement system activation. However, some aspects of the immune mechanisms are unique. Both targets (AChR and AQP4) are expressed in the periphery and CNS, but MG mainly affects the NMJ in the periphery outside of CNS, whereas NMO preferentially involves the CNS. Inflammatory cells, including B cells and macrophages, often infiltrate the thymus but not the target—muscle in MG, whereas the infiltration of inflammatory cells, mainly polymorphonuclear leukocytes and macrophages, in NMO, is always observed in the target organ—the spinal cord. A review of the common and discrepant characteristics of these two autoimmune channelopathies may expand our understanding of the pathogenic mechanism of both disorders and assist in the development of proper treatments in the future.
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Affiliation(s)
- Zhen Wang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, China.,Tianjin Medical University General Hospital, Tianjin Neurological Institute, Tianjin, China
| | - Yaping Yan
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, China
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7
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Genetic basis of myasthenia gravis – A comprehensive review. J Autoimmun 2014; 52:146-53. [DOI: 10.1016/j.jaut.2013.12.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 12/02/2013] [Indexed: 11/24/2022]
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8
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Rahman MA, Masuda A, Ohe K, Ito M, Hutchinson DO, Mayeda A, Engel AG, Ohno K. HnRNP L and hnRNP LL antagonistically modulate PTB-mediated splicing suppression of CHRNA1 pre-mRNA. Sci Rep 2013; 3:2931. [PMID: 24121633 PMCID: PMC3796306 DOI: 10.1038/srep02931] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/25/2013] [Indexed: 12/20/2022] Open
Abstract
CHRNA1 gene, encoding the muscle nicotinic acetylcholine receptor alpha subunit, harbors an inframe exon P3A. Inclusion of exon P3A disables assembly of the acetylcholine receptor subunits. A single nucleotide mutation in exon P3A identified in congenital myasthenic syndrome causes exclusive inclusion of exon P3A. The mutation gains a de novo binding affinity for a splicing enhancing RNA-binding protein, hnRNP LL, and displaces binding of a splicing suppressing RNA-binding protein, hnRNP L. The hnRNP L binds to another splicing repressor PTB through the proline-rich region and promotes PTB binding to the polypyrimidine tract upstream of exon P3A, whereas hnRNP LL lacking the proline-rich region cannot bind to PTB. Interaction of hnRNP L with PTB inhibits association of U2AF(65) and U1 snRNP with the upstream and downstream of P3A, respectively, which causes a defect in exon P3A definition. HnRNP L and hnRNP LL thus antagonistically modulate PTB-mediated splicing suppression of exon P3A.
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Affiliation(s)
- Mohammad Alinoor Rahman
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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Pasqualoni E, Aubart F, Brihaye B, Sacré K, Maisonobe T, Laissy JP, Lidove O, Papo T. Lambert–Eaton Myasthenic syndrome and follicular thymic hyperplasia in systemic lupus erythematosus. Lupus 2011; 20:745-8. [DOI: 10.1177/0961203310393769] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- E Pasqualoni
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - F Aubart
- Department of Neurophysiology, Pitié-Salpetrière Hospital, Paris, France
| | - B Brihaye
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - K Sacré
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - T Maisonobe
- Department of Neurophysiology, Pitié-Salpetrière Hospital, Paris, France
| | - J-P Laissy
- Department of Radiology, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - O Lidove
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
| | - T Papo
- Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France
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Masuda A, Shen XM, Ito M, Matsuura T, Engel AG, Ohno K. hnRNP H enhances skipping of a nonfunctional exon P3A in CHRNA1 and a mutation disrupting its binding causes congenital myasthenic syndrome. Hum Mol Genet 2008; 17:4022-35. [PMID: 18806275 PMCID: PMC2638575 DOI: 10.1093/hmg/ddn305] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 09/01/2008] [Accepted: 09/17/2008] [Indexed: 12/28/2022] Open
Abstract
In humans and great apes, CHRNA1 encoding the muscle nicotinic acetylcholine receptor alpha subunit carries an inframe exon P3A, the inclusion of which yields a nonfunctional alpha subunit. In muscle, the P3A(-) and P3A(+) transcripts are generated in a 1:1 ratio but the functional significance and regulation of the alternative splicing remain elusive. An intronic mutation (IVS3-8G>A), identified in a patient with congenital myasthenic syndrome, disrupts an intronic splicing silencer (ISS) and results in exclusive inclusion of the downstream P3A exon. We found that the ISS-binding splicing trans-factor was heterogeneous nuclear ribonucleoprotein (hnRNP) H and the mutation attenuated the affinity of hnRNP for the ISS approximately 100-fold. We next showed that direct placement of hnRNP H to the 3' end of intron 3 silences, and siRNA-mediated downregulation of hnRNP H enhances recognition of exon P3A. Analysis of the human genome suggested that the hnRNPH-binding UGGG motif is overrepresented close to the 3' ends of introns. Pursuing this clue, we showed that alternative exons of GRIP1, FAS, VPS13C and NRCAM are downregulated by hnRNP H. Our findings imply that the presence of the hnRNP H-binding motif close to the 3' end of an intron is an essential but underestimated splicing regulator of the downstream exon.
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Affiliation(s)
- Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Xin-Ming Shen
- Department of Neurology, Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tohru Matsuura
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Andrew G. Engel
- Department of Neurology, Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of Neurology, Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN, USA
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Maclennan CA, Vincent A, Marx A, Willcox N, Gilhus NE, Newsom-Davis J, Beeson D. Preferential expression of AChR epsilon-subunit in thymomas from patients with myasthenia gravis. J Neuroimmunol 2008; 201-202:28-32. [PMID: 18657869 DOI: 10.1016/j.jneuroim.2008.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 11/19/2022]
Abstract
The role of antigen expression by thymomas in myasthenia gravis (MG) is not clear. Previous reports of acetylcholine receptor (AChR) mRNA expression by the highly sensitive reverse transcription-polymerase chain reactions (RT-PCR) produced varying results. To try to clarify this issue, we first used RT-PCR but then turned to the more accurate and quantitative RNase protection assays (RPA) to assess AChR subunit mRNA expression in thymomas from 25 patients (22 with MG). By RT-PCR, all five AChR subunits could be detected in many thymomas. However, by RPA, the mRNA for the adult-specific AChR epsilon-subunit was found in 13/25 (52%) thymomas, but not mRNA for the other subunits. AChR epsilon-subunit was more frequently detected in thymomas of A or AB histology (WHO classification) than those with B1-B3 histology. Overall, 6/6 with thymomas of A or AB histology were positive compared with only 8/19 with B histology (p=0.02). Autoantibodies in the two patients with the highest levels of epsilon-subunit mRNA bound better to adult (alpha(2)betadeltaepsilon) AChR than to fetal (alpha(2)betadeltagamma) AChR, whereas the other sera bound better to fetal AChR. The greater abundance of mRNA for AChR epsilon-subunit than for other subunits suggests that the AChR epsilon-subunit may play a distinctive role in autosensitization in MG-associated thymomas, particularly those of type A or AB.
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Affiliation(s)
- Calman A Maclennan
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
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Camdessanché JP, Lassablière F, Meyronnet D, Férraud K, Absi L, Honnorat J, Antoine JC. Expression of the onconeural CV2/CRMP5 antigen in thymus and thymoma. J Neuroimmunol 2006; 174:168-73. [PMID: 16519949 DOI: 10.1016/j.jneuroim.2006.01.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 01/24/2006] [Accepted: 01/31/2006] [Indexed: 10/24/2022]
Abstract
Anti-CV2 antibodies (AB) react with the developmentally regulated neural proteins CRMPs and particularly with CRMP5. They occur with small cell lung cancer (SCLC) and thymoma. SCLCs universally express CRMP5. We investigated the expression of CRMPs in thymoma and thymus. In thymoma, none of the CRMPs were detected by immunohistochemistry in tumorous epithelial cells with specific antibodies including CRMP5 but an antibody reacting with a peptide common to the CRMPs labeled a 66-kDa protein in Western blot of rat brain, thymus, and thymoma extracts. Thus, the normal CRMP5 is probably not expressed by tumorous epithelial cells. These results indicate that the mechanisms leading to CRMP5 autoimmunization are different in SCLC and thymoma.
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Shiono H, Roxanis I, Zhang W, Sims GP, Meager A, Jacobson LW, Liu JL, Matthews I, Wong YL, Bonifati M, Micklem K, Stott DI, Todd JA, Beeson D, Vincent A, Willcox N. Scenarios for autoimmunization of T and B cells in myasthenia gravis. Ann N Y Acad Sci 2003; 998:237-56. [PMID: 14592881 DOI: 10.1196/annals.1254.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have studied responses in thymoma patients to interferon-alpha and to the acetylcholine receptor (AChR) in early-onset myasthenia gravis (EOMG), seeking clues to autoimmunizing mechanisms. Our new evidence implicates a two-step process: (step 1) professional antigen-presenting cells and thymic epithelial cells prime AChR-specific T cells; then (step 2) thymic myoid cells subsequently provoke germinal center formation in EOMG. Our unifying hypothesis proposes that AChR epitopes expressed by neoplastic or hyperplastic thymic epithelial cells aberrantly prime helper T cells, whether generated locally or infiltrating from the circulation. These helper T cells then induce antibody responses against linear epitopes that cross-react with whole AChR and attack myoid cells in the EOMG thymus. The resulting antigen-antibody complexes and the recruitment of professional antigen-presenting cells increase the exposure of thymic cells to the infiltrates and provoke local germinal center formation and determinant spreading. Both these and the consequently enhanced heterogeneity and pathogenicity of the autoantibodies should be minimized by early thymectomy.
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Affiliation(s)
- H Shiono
- Neuroscience Group, Weatherall Institute for Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
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14
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Marx A, Müller-Hermelink HK, Ströbel P. The Role of Thymomas in the Development of Myasthenia Gravis. Ann N Y Acad Sci 2003; 998:223-36. [PMID: 14592880 DOI: 10.1196/annals.1254.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thymic pathology occurs in 80-90% of myasthenia gravis patients. Significant associations between different thymic alterations and clinical findings are discussed. To highlight peculiarities in thymoma-associated myasthenia gravis, we briefly review myasthenia gravis associated with thymic lymphofollicular hyperplasia (TFH) and thymic atrophy.
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Affiliation(s)
- Alexander Marx
- Institute of Pathology, University of Würzburg, D-97080 Würzburg, Germany.
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15
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Suzuki S, Tanaka K, Yasuoka H, Fukuuchi Y, Kawakami Y, Kuwana M. Autoreactive T cells to the P3A+ isoform of AChR alpha subunit in myasthenia gravis. J Neuroimmunol 2003; 137:177-86. [PMID: 12667662 DOI: 10.1016/s0165-5728(03)00078-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In vitro T cell proliferative response to an alternative splicing variant of acetylcholine receptor alpha subunit (AChR alpha) with the P3A exon-encoded region was examined in peripheral blood samples from 28 myasthenia gravis (MG) patients and 14 healthy donors using recombinant fragments and synthetic peptides. T cells responsive to the P3A region-specific sequences were detected in five MG patients, all of whom were late-onset disease with thymoma, but in none of healthy donors. These autoreactive T cells may be involved in the pathogenic process in a subset of MG patients.
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Affiliation(s)
- Shigeaki Suzuki
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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16
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Navaneetham D, Penn AS, Howard JF, Conti-Fine BM. Human thymuses express incomplete sets of muscle acetylcholine receptor subunit transcripts that seldom include the delta subunit. Muscle Nerve 2001; 24:203-10. [PMID: 11180203 DOI: 10.1002/1097-4598(200102)24:2<203::aid-mus50>3.0.co;2-f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In myasthenia gravis (MG) the muscle acetylcholine receptor (AChR) is the target of an immune response that might begin in the thymus. The thymus expresses binding sites for specific ligands of muscle AChR, a complex protein composed of alpha, beta, gamma (or epsilon) and delta subunits. The thymus expresses the AChR alpha subunit, but there is controversy regarding the expression in the thymus of the gamma, epsilon and delta subunits. We investigated the presence of messenger RNA (mRNA) for the different muscle AChR subunits in thymus tissue from 20 healthy subjects and 13 myasthenic patients. We detected mRNA for the alpha and epsilon subunits in all samples, for the beta subunit in all but one sample and for the gamma subunit in most samples although at lower levels than the epsilon subunit. Myasthenic thymuses expressed levels of gamma subunit mRNA similar to control thymuses but more abundant epsilon subunit mRNA. None of the myasthenic thymuses and only two control thymuses expressed detectable delta subunit mRNA. This supports the hypothesis that human thymus may express AChR proteins that do not include the delta subunit. Such receptors, which would have different antigenic structure than the muscle AChRs, might have a role in triggering the autoimmune response that causes MG.
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Affiliation(s)
- D Navaneetham
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 1479 Gortner Ave, St. Paul, Minnesota 55108, USA
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17
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Thymomas alter the T-cell subset composition in the blood: a potential mechanism for thymoma-associated autoimmune disease. Blood 2000. [DOI: 10.1182/blood.v96.12.3872] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Thymomas are the only tumors that are proven to generate mature T cells from immature precursors. It is unknown, however, whether intratumorous thymopoiesis has an impact on the peripheral T-cell pool and might thus be related to the high frequency of thymoma-associated myasthenia gravis. This study shows, using fluorescence-activated cell sorting-based analyses and T-cell proliferation assays, that thymopoiesis and T-cell function in thymomas correspond with immunologic alterations in the blood. Specifically, the proportion of circulating CD45RA+CD8+ T cells is significantly increased in patients with thymoma compared with normal controls, in accordance with intratumorous T-cell development that is abnormally skewed toward the CD8+ phenotype. Moreover, it is primarily the proportion of circulating CD45RA+CD8+ T cells that decreases after thymectomy. The results also demonstrate that T cells reactive toward recombinant autoantigens are distributed equally between thymomas and blood, whereas T-cell responses to foreign antigen (ie, tetanus toxoid) are seen only among circulating T cells and not among thymoma-derived T cells. These functional studies support the hypothesis that thymopoiesis occurring within thymomas alters the peripheral T-cell repertoire. Because many thymomas are enriched with autoantigen-specific T cells, a disturbance of circulating T-cell subset composition by export of intratumorous T cells may contribute to paraneoplastic autoimmune disease arising in patients with thymoma.
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18
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Thymomas alter the T-cell subset composition in the blood: a potential mechanism for thymoma-associated autoimmune disease. Blood 2000. [DOI: 10.1182/blood.v96.12.3872.h8003872_3872_3879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thymomas are the only tumors that are proven to generate mature T cells from immature precursors. It is unknown, however, whether intratumorous thymopoiesis has an impact on the peripheral T-cell pool and might thus be related to the high frequency of thymoma-associated myasthenia gravis. This study shows, using fluorescence-activated cell sorting-based analyses and T-cell proliferation assays, that thymopoiesis and T-cell function in thymomas correspond with immunologic alterations in the blood. Specifically, the proportion of circulating CD45RA+CD8+ T cells is significantly increased in patients with thymoma compared with normal controls, in accordance with intratumorous T-cell development that is abnormally skewed toward the CD8+ phenotype. Moreover, it is primarily the proportion of circulating CD45RA+CD8+ T cells that decreases after thymectomy. The results also demonstrate that T cells reactive toward recombinant autoantigens are distributed equally between thymomas and blood, whereas T-cell responses to foreign antigen (ie, tetanus toxoid) are seen only among circulating T cells and not among thymoma-derived T cells. These functional studies support the hypothesis that thymopoiesis occurring within thymomas alters the peripheral T-cell repertoire. Because many thymomas are enriched with autoantigen-specific T cells, a disturbance of circulating T-cell subset composition by export of intratumorous T cells may contribute to paraneoplastic autoimmune disease arising in patients with thymoma.
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19
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Reis Filho JS, Milanezi MF, Moreira CG, Werneck LC, Boscardin P, Ioshii SO, Schmitt FC. Invasive medullary thymoma associated with Myasthenia gravis: an unusual case. ARQUIVOS DE NEURO-PSIQUIATRIA 2000; 58:1110-4. [PMID: 11105080 DOI: 10.1590/s0004-282x2000000600020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thymomas are tumors characterized by a remarkable morphological heterogeneity and variable clinical behavior. This tumor has unique clinical associations, most notably with hematological abnormalities and myasthenia gravis. According with the Müller-Hermelink criteria, there are significant differences between the histological types of thymomas and the association with myasthenia gravis. Among the different histological types, medullary thymoma is the least frequent variant associated with this autoimmune disease. In this report we describe a case of medullary thymoma presenting in a 71-year- old woman with a myasthenic syndrome.
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Affiliation(s)
- J S Reis Filho
- Hospital de Clínicas, Universidade Federal do Paraná, Sao Paulo, Brazil.
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20
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Abstract
Thymomas are fascinating tumors because of their multifaceted clinical presentation, including an unrivaled frequency of associated paraneoplastic autoimmune diseases and an astounding histologic heterogeneity. Thus, thymomas challenge the clinician, pathologist, and immunologist alike with complex diagnostic and therapeutic problems in almost all fields of medicine, radiology, nuclear medicine, surgery, radiooncology, and pathology. This review highlights recent progress in these fields, including the new World Health Organization's classification of thymomas, and reports on the beginning discovery of the genetic basis of thymoma oncogenesis and the cellular and molecular immunopathology of thymoma-associated paraneoplastic autoimmunity.
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21
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Mocchegiani E, Giacconi R, Muzzioli M, Gasparini N, Provinciali L, Spazzafumo L, Licastro F. Different age-related effects of thymectomy in myasthenia gravis: role of thymoma, zinc, thymulin, IL-2 and IL-6. Mech Ageing Dev 2000; 117:79-91. [PMID: 10958925 DOI: 10.1016/s0047-6374(00)00145-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Different age-related immune pathogenetic mechanisms in myasthenia gravis (MG) have been suggested because of restoration after thymectomy (Tx) of altered zinc, thymulin (TH) and T-cell subsets exclusively in early-onset patients (younger <50 years), not in late-onset patients (older >50 years). In this context interleukin-2 (IL-2), interleukin-6 (IL-6) and thymoma are crucial because both involved in MG pathogenesis and correlated with acetylcholine receptors (AchRs) Ab production. Moreover, IL-2 and IL-6 are zinc-dependent, are altered in aging and related with zinc and TH age-dependent declines. Moreover, zinc is relevant for immune efficiency. In order to confirm these different age-related pathogenetic mechanisms further, the role of thymoma, zinc, TH, IL-2 and IL-6 is studied in MG patients with generalized MG with and without thymoma before and 1 month and 1 year after Tx. The high IL-2, IL-6, zinc, and AChR Ab levels observed before Tx are significantly correlated each other in younger MG patients (<50 years) independently by thymoma and in older MG patients (>50 years) with thymoma. No correlations exist in older MG patients without thymoma. Thymulin is not correlated with other parameters considered to be both in younger and older MG patients independently by the thymoma. Thymectomy restores zinc; immune parameters and AChR Ab are exclusively in the younger group, not in the older one. These findings suggest that IL-2 and IL-6, via zinc, rather than TH, may be involved in different age-related pathogenetic mechanisms mainly in early-onset MG. By contrast, thymoma may be involved in MG etiology in late-onset representing, as such, a useful discriminant tool for MG etiology between early and late-onset MG patients. Because autoimmune phenomena may rise in aging, a parallelism with altered immune functions during aging is discussed.
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Affiliation(s)
- E Mocchegiani
- Immunology Center, (Section Nutrition, Immunity and Aging), Gerontological Research Department 'Nino Masera', Italian National Research Centers on Aging (INRCA), Via Birarelli 8, 60121, Ancona, Italy.
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22
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Kadota Y, Okumura M, Miyoshi S, Kitagawa-Sakakida S, Inoue M, Shiono H, Maeda Y, Kinoshita T, Shirakura R, Matsuda H. Altered T cell development in human thymoma is related to impairment of MHC class II transactivator expression induced by interferon-gamma (IFN-gamma). Clin Exp Immunol 2000; 121:59-68. [PMID: 10886240 PMCID: PMC1905672 DOI: 10.1046/j.1365-2249.2000.01256.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Thymoma is known to contain CD4+CD8+ T cells, indicating that neoplastic epithelial cells of thymoma have a function as thymic cortical epithelium. However, it has been shown that there is an impairment of CD4+ T cell development in thymoma and that IFN-gamma-induced HLA-DR expression on cultured thymic epithelial cells (TEC) derived from thymoma is decreased when compared with the normal thymus. MHC class II transactivator (CIITA) is known to play a critical role in IFN-gamma-induced MHC II expression. In this study, we attempted to elucidate whether CIITA is responsible for the impaired up-regulation of MHC II molecules in response to IFN-gamma in thymoma TEC. A quantitative reverse transriptase-polymerase chain reaction examination revealed that the induced level of CIITA was significantly lower in thymoma TEC than in normal TEC. The induced levels of invariant chain (Ii) and HLA-DR in thymoma TEC were correlated with CIITA expression. The proportion of CD3+ cells in the CD4+CD8- subset in thymoma was also correlated with CIITA expression. A gel mobility shift assay however, revealed translocation of STAT1 to the nucleus in thymoma as well as normal TEC. Intercellular adhesion molecule-1 was up-regulated in the thymoma TEC to a level similar to normal TEC in response to IFN-gamma. These results indicate that impaired up-regulation of HLA-DR in response to IFN-gamma results from insufficient induction of CIITA, but not from the signal from IFN-gamma receptor to the nucleus. The abnormal regulation of HLA-DR expression caused by impaired induction of CIITA may affect CD4+ T cell development in thymoma.
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Affiliation(s)
- Y Kadota
- Division of Organ Transplantation, Biomedical Research Center, Osaka, Japan
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23
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Marx A, Müller-Hermelink HK. From basic immunobiology to the upcoming WHO-classification of tumors of the thymus. The Second Conference on Biological and Clinical Aspects of Thymic Epithelial Tumors and related recent developments. Pathol Res Pract 1999; 195:515-33. [PMID: 10483582 DOI: 10.1016/s0344-0338(99)80001-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Second Conference on Biological and Clinical Aspects of Thymic Epithelial Tumors in Leiden, The Netherlands, 1998, set the stage for an interdisciplinary meeting of immunologists, pathologists and members of various clinical disciplines to exchange their recent findings in the field of thymus-related biology, pathology, and medicine. The contributions covered such diverse subjects as the role of transcription factors and cytokines in the development of the thymic microenvironment, thymic T, B and NK cell development, the pathogenesis of myasthenia gravis and other thymoma-associated autoimmunities, the pathology of thymic epithelial tumors and germ cell neoplasms, and new approaches to their diagnosis and treatment. This editorial will briefly sum up the data presented at the Conference and will comment on related novel findings that have been reported since then. Because it was also at the Leiden Conference, that the proposal of the WHO committee for the classification of thymic tumors was discussed for the first time, a description of the upcoming WHO Classification of Tumors of the Thymus is given with emphasis on the diagnostic criteria of thymic epithelial tumors, that should now be termed as type A, AB, B1-3 and type C thymomas, to make pathological and clinical studies comparable in the future.
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