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Kirschstein T, Köhling R. Functional changes in neuronal circuits due to antibody-driven autoimmune response. Neurobiol Dis 2023:106221. [PMID: 37414365 DOI: 10.1016/j.nbd.2023.106221] [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: 12/14/2022] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023] Open
Abstract
Autoimmune-mediated encephalitis syndromes are increasingly being recognized as important clinical entities. They need to be thought of as differential diagnosis in any patient presenting with fast-onset psychosis or psychiatric problems, memory deficits or other cognitive problems, including aphasias, as well as seizures or motor automatisms, but also rigidity, paresis, ataxia or dystonic / parkinsonian symptoms. Diagnosis including imaging and CSF search for antibodies needs to be fast, as progression of these inflammatory processes is often causing scarring of brain tissue, with hypergliosis and atrophy. As these symptoms show, the autoantibodies present in these cases appear to act within the CNS. Several of such antibodies have by now been identified such as IgG directed against NMDA-receptors, AMPA receptors, GABAA and GABAB receptors, and voltage gated potassium channels and proteins of the potassium channel complex (i.e. LGI1 and CASPR2). These are neuropil / surface antigens where antibody interaction can well be envisaged to cause dysfunction of the target protein, including internalization. Others, such as antibodies directed against GAD65 (an intracellular enzyme responsible for GABA-synthesis from glutamate), are discussed to constitute epiphenomena, but not causal agents in disease progression. This review will focus on the current knowledge of antibody interaction mechanisms, especially discussing cellular excitability changes and synaptic interactions in hippocampal and other brain networks. One challenge in this context is to find viable hypotheses for the emergence of both, hyperexcitability and seizures, and presumably reduced synaptic plasticity and underlying cognitive dysfunction.
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Affiliation(s)
- Timo Kirschstein
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany; Center for Translational Neuroscience Research, Rostock University Medical Center, 18057 Rostock, Germany
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany; Center for Translational Neuroscience Research, Rostock University Medical Center, 18057 Rostock, Germany.
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Mori S, Suzuki S, Konishi T, Kawaguchi N, Kishi M, Kuwabara S, Ishizuchi K, Zhou H, Shibasaki F, Tsumoto H, Omura T, Miura Y, Mori S, Higashihara M, Murayama S, Shigemoto K. Proteolytic ectodomain shedding of muscle-specific tyrosine kinase in myasthenia gravis. Exp Neurol 2023; 361:114300. [PMID: 36525997 DOI: 10.1016/j.expneurol.2022.114300] [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: 07/12/2022] [Revised: 11/07/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022]
Abstract
Autoantibodies to muscle-specific tyrosine kinase (MuSK) proteins at the neuromuscular junction (NMJ) cause refractory generalized myasthenia gravis (MG) with dyspnea more frequently than other MG subtypes. However, the mechanisms via which MuSK, a membrane protein locally expressed on the NMJ of skeletal muscle, is supplied to the immune system as an autoantigen remains unknown. Here, we identified MuSK in both mouse and human serum, with the amount of MuSK dramatically increasing in mice with motor nerve denervation and in MG model mice. Peptide analysis by liquid chromatography-tandem-mass spectrometry (LC-MS/MS) confirmed the presence of MuSK in both human and mouse serum. Furthermore, some patients with MG have significantly higher amounts of MuSK in serum than healthy controls. Our results indicated that the secretion of MuSK proteins from muscles into the bloodstream was induced by ectodomain shedding triggered by neuromuscular junction failure. The results may explain why MuSK-MG is refractory to treatments and causes rapid muscle atrophy in some patients due to the denervation associated with Ab-induced disruption of neuromuscular transmission at the NMJ. Such discoveries pave the way for new MG treatments, and MuSK may be used as a biomarker for other neuromuscular diseases in preclinical studies, clinical diagnostics, therapeutics, and drug discovery.
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Affiliation(s)
- Shuuichi Mori
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan
| | - Shigeaki Suzuki
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | | | - Naoki Kawaguchi
- Dowa Institute of Clinical Neuroscience, Neurology Clinic Chiba, Chiba, Japan
| | - Masahiko Kishi
- Department of Internal Medicine, Toho University Sakura Medical Center, Chiba, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Chiba University School of Medicine, Chiba, Japan
| | - Kei Ishizuchi
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Heying Zhou
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan
| | - Futoshi Shibasaki
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hiroki Tsumoto
- Research Team for Mechanism of Aging, TMIG, Tokyo, Japan
| | - Takuya Omura
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan
| | - Yuri Miura
- Research Team for Mechanism of Aging, TMIG, Tokyo, Japan
| | - Seijiro Mori
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan
| | - Mana Higashihara
- Department of Neurology, Tokyo Metropolitan Geriatric Hospital, Tokyo (TMGHIG), Japan
| | | | - Kazuhiro Shigemoto
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology (TMIG), Tokyo, Japan.
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3
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Tang M, Shao Y, Dong J, Gao X, Wei S, Ma J, Hong Y, Li Z, Bi T, Yin Y, Zhang W, Liu W. Risk factors for postoperative myasthenia gravis in patients with thymoma without myasthenia gravis: A systematic review and meta-analysis. Front Oncol 2023; 13:1061264. [PMID: 36845745 PMCID: PMC9944936 DOI: 10.3389/fonc.2023.1061264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction According to the principle, thymomas combined with myasthenia gravis (MG) require surgical treatment. However, patients with non-MG thymoma rarely develop MG and early- or late-onset MG after surgery is called postoperative MG (PMG). Our study used a meta-analysis to examine the incidence of PMG and risk factors. Methods Relevant studies were searched for in the PubMed, EMBASE, Web of Science, CNKI,and Wanfang databases. Investigations that directly or indirectly analyzed the risk factors for PMG development in patients with non-MG thymoma were included in this study. Furthermore, risk ratios (RR) with 95% confidence intervals (CI) were pooled using meta-analysis, and fixed-effects or random-effects models were used depending on the heterogeneity of the included studies. Results Thirteen cohorts containing 2,448 patients that met the inclusion criteria were included. Metaanalysis revealed that the incidence of PMG in preoperative patients with non-MG thymoma was 8%. Preoperative seropositive acetylcholine receptor antibody (AChR-Ab) (RR = 5.53, 95% CI 2.36 - 12.96, P<0.001), open thymectomy (RR =1.84, 95% CI 1.39 - 2.43, P<0.001), non-R0 resection (RR = 1.87, 95% CI 1.36 - 2.54, P<0.001), world health organization (WHO) type B (RR =1.80, 95% CI 1.07 - 3.04, P= 0.028), and postoperative inflammation (RR = 1.63, 95% CI 1.26 - 2.12, P<0.001) were the risk factors for PMG in patients with thymoma. Masaoka stage (P = 0.151) and sex (P = 0.777) were not significantly associated with PMG. Discussion Patients with thymoma but without MG had a high probability of developing PMG. Although the incidence of PMG was very low, thymectomy could not completely prevent the occurrence of MG. Preoperative seropositive AChR-Ab level, open thymectomy, non-R0 resection, WHO type B, and postoperative inflammation were risk factors for PMG. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022360002.
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Affiliation(s)
- Mingbo Tang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yifeng Shao
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Junxue Dong
- Laboratory of Infection Oncology, Institute of Clinical Molecular Biology, Universitätsklinikum Schleswig-Holstein (UKSH), Christian Albrechts University of Kiel, Kiel, Germany
| | - Xinliang Gao
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Shixiong Wei
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Jianzun Ma
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yang Hong
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Zhiqin Li
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Taiyu Bi
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yipeng Yin
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Wenyu Zhang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Wei Liu
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China,*Correspondence: Wei Liu,
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He X, Zhou S, Ji Y, Zhang Y, Lv J, Quan S, Zhang J, Zhao X, Cui W, Li W, Liu P, Zhang L, Shen T, Fang H, Yang J, Zhang Y, Cui X, Zhang Q, Gao F. Sorting nexin 17 increases low-density lipoprotein receptor-related protein 4 membrane expression: A novel mechanism of acetylcholine receptor aggregation in myasthenia gravis. Front Immunol 2022; 13:916098. [PMID: 36311763 PMCID: PMC9601310 DOI: 10.3389/fimmu.2022.916098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/26/2022] [Indexed: 11/24/2022] Open
Abstract
Myasthenia gravis (MG) is characterized by autoimmune damage to the postsynaptic membrane of the neuromuscular junction (NMJ) with impaired postsynaptic acetylcholine receptor (AChR) aggregation. Low-density lipoprotein receptor-related protein 4 (LRP4) plays an important role in AChR aggregation at endplate membranes via the Agrin–LRP4–muscle-specific receptor tyrosine kinase (MuSK) cascade. Sorting nexin 17 (SNX17) regulates the degradation and recycling of various internalized membrane proteins. However, whether SNX17 regulates LRP4 remains unclear. Therefore, we examined the regulatory effects of SNX17 on LRP4 and its influence on AChR aggregation in MG. We selected C2C12 myotubes and induced LRP4 internalization via stimulation with anti-LRP4 antibody and confirmed intracellular interaction between SNX17 and LRP4. SNX17 knockdown and overexpression confirmed that SNX17 promoted MuSK phosphorylation and AChR aggregation by increasing cell surface LRP4 expression. By establishing experimental autoimmune MG (EAMG) mouse models, we identified that SNX17 upregulation improved fragmentation of the AChR structure at the NMJ and alleviated leg weakness in EAMG mice. Thus, these results reveal that SNX17 may be a novel target for future MG therapy.
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Affiliation(s)
- Xiaoxiao He
- BGI College, Zhengzhou University, Zhengzhou, China
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shuxian Zhou
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
- Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Ying Ji
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
- Department of Neurology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yingna Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jie Lv
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shangkun Quan
- Department of Pathophysiology, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Jing Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xue Zhao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Weike Cui
- BGI College, Zhengzhou University, Zhengzhou, China
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Wenbo Li
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
- Department of Neurology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Peipei Liu
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
- Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Linyuan Zhang
- BGI College, Zhengzhou University, Zhengzhou, China
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Tong Shen
- Department of Encephalopathy, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Hua Fang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Junhong Yang
- Department of Encephalopathy, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Yunke Zhang
- Department of Encephalopathy, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Xinzheng Cui
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Qingyong Zhang
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People’s Hospital, Zhengzhou, China
| | - Feng Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
- *Correspondence: Feng Gao,
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Ceccanti M, Libonati L, Ruffolo G, Cifelli P, Moret F, Frasca V, Palma E, Inghilleri M, Cambieri C. Effects of 3,4-diaminopyridine on myasthenia gravis: Preliminary results of an open-label study. Front Pharmacol 2022; 13:982434. [PMID: 36052140 PMCID: PMC9424766 DOI: 10.3389/fphar.2022.982434] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
Background: 3,4-diaminopyridine (3,4-DAP) can lead to clinical and electrophysiological improvement in myasthenic syndrome; it may thus represent a valuable therapeutic option for patients intolerant to pyridostigmine. Objective: to assess 3,4-diaminopyridine (3,4-DAP) effects and tolerability in patients with anti-AChR myasthenia gravis. Method: Effects were monitored electrophysiologically by repetitive nerve stimulation (RNS) and by standardized clinical testing (QMG score) before and after a single dose administration of 3,4-DAP 10 mg per os in 15 patients. Patients were divided according to their Myasthenia Gravis Foundation of America (MGFA) class into mild and severe. Results: No significant side effects were found, apart from transient paresthesia. 3,4-DAP had a significant effect on the QMG score (p = 0.0251), on repetitive nerve stimulation (p = 0.0251), and on the forced vital capacity (p = 0.03), thus indicating that it may reduce the level of disability and the decremental muscle response. When the patients were divided according to the MGFA classification, 3,4-DAP showed a positive effect in the severe group, either for the QMG score (p = 0.031) or for the RNS decrement (p = 0.031). No significant difference was observed in any of the outcome measures within the mild group (p > 0.05). A direct effect of 3,4-DAP on nicotinic ACh receptors (nAChRs) was excluded since human nAChRs reconstituted in an expression system, which were not affected by 3,4-DAP application. Conclusion: Our results suggest that 3,4-DAP may be a useful add-on therapy, especially in most severe patients or when immunosuppressive treatment has not yet reached its full effect or when significant side-effects are associated with anticholinesterase.
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Affiliation(s)
- Marco Ceccanti
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
| | - Laura Libonati
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Institute Pasteur- Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
- IRCCS San Raffaele Pisana, Rome, Italy
| | - Pierangelo Cifelli
- Department of Applied Clinical and Biotechnological Sciences, University of L'Aquila, L'Aquila, Italy
| | - Federica Moret
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
| | - Vittorio Frasca
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Institute Pasteur- Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Maurizio Inghilleri
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
| | - Chiara Cambieri
- Neuromuscular Disorders Unit, Department of Human Neurosciences, Sapienza University, Rome, Italy
- *Correspondence: Chiara Cambieri,
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Lenti MV, Rossi CM, Melazzini F, Gastaldi M, Bugatti S, Rotondi M, Bianchi PI, Gentile A, Chiovato L, Montecucco C, Corazza GR, Di Sabatino A. Seronegative autoimmune diseases: A challenging diagnosis. Autoimmun Rev 2022; 21:103143. [PMID: 35840037 DOI: 10.1016/j.autrev.2022.103143] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/10/2022] [Indexed: 12/19/2022]
Abstract
Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.
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Affiliation(s)
- Marco Vincenzo Lenti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Carlo Maria Rossi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Federica Melazzini
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Serena Bugatti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Mario Rotondi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Paola Ilaria Bianchi
- Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonella Gentile
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Luca Chiovato
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Carlomaurizio Montecucco
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Gino Roberto Corazza
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonio Di Sabatino
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy.
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Klaus B, Müller P, van Wickeren N, Dordevic M, Schmicker M, Zdunczyk Y, Brigadski T, Leßmann V, Vielhaber S, Schreiber S, Müller NG. OUP accepted manuscript. Brain Commun 2022; 4:fcac018. [PMID: 35198977 PMCID: PMC8856136 DOI: 10.1093/braincomms/fcac018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/05/2021] [Accepted: 01/31/2022] [Indexed: 11/14/2022] Open
Abstract
Myasthenia gravis is an autoimmune disease affecting neuromuscular transmission and causing skeletal muscle weakness. Additionally, systemic inflammation, cognitive deficits and autonomic dysfunction have been described. However, little is known about myasthenia gravis-related reorganization of the brain. In this study, we thus investigated the structural and functional brain changes in myasthenia gravis patients. Eleven myasthenia gravis patients (age: 70.64 ± 9.27; 11 males) were compared to age-, sex- and education-matched healthy controls (age: 70.18 ± 8.98; 11 males). Most of the patients (n = 10, 0.91%) received cholinesterase inhibitors. Structural brain changes were determined by applying voxel-based morphometry using high-resolution T1-weighted sequences. Functional brain changes were assessed with a neuropsychological test battery (including attention, memory and executive functions), a spatial orientation task and brain-derived neurotrophic factor blood levels. Myasthenia gravis patients showed significant grey matter volume reductions in the cingulate gyrus, in the inferior parietal lobe and in the fusiform gyrus. Furthermore, myasthenia gravis patients showed significantly lower performance in executive functions, working memory (Spatial Span, P = 0.034, d = 1.466), verbal episodic memory (P = 0.003, d = 1.468) and somatosensory-related spatial orientation (Triangle Completion Test, P = 0.003, d = 1.200). Additionally, serum brain-derived neurotrophic factor levels were significantly higher in myasthenia gravis patients (P = 0.001, d = 2.040). Our results indicate that myasthenia gravis is associated with structural and functional brain alterations. Especially the grey matter volume changes in the cingulate gyrus and the inferior parietal lobe could be associated with cognitive deficits in memory and executive functions. Furthermore, deficits in somatosensory-related spatial orientation could be associated with the lower volumes in the inferior parietal lobe. Future research is needed to replicate these findings independently in a larger sample and to investigate the underlying mechanisms in more detail.
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Affiliation(s)
- Benita Klaus
- Correspondence to: Benita Klaus German Center for Neurodegenerative Diseases (DZNE) Leipziger Str 44 Haus 64, D-39120 Magdeburg, Germany E-mail:
| | - Patrick Müller
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Nora van Wickeren
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Milos Dordevic
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Marlen Schmicker
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Yael Zdunczyk
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Tanja Brigadski
- Institute of Physiology, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Department of Informatics and Microsystems Technology, University of Kaiserslautern, 67659 Zweibrücken, Germany
| | - Volkmar Leßmann
- Institute of Physiology, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
| | - Stefan Vielhaber
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
| | - Stefanie Schreiber
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
| | - Notger G. Müller
- German Centre for Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Department of Neurology, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Faculty of Health Sciences, University of Potsdam, 14476 Potsdam, Germany
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Abstract
PURPOSE OF REVIEW To provide an update on recent developments regarding acquired, antibody-mediated, neuromuscular hyperexcitability syndromes, including Isaac's and Morvan's syndromes, cramp-fasciculation syndrome and rippling muscle disease, and their genetic differential diagnoses. RECENT FINDINGS Antibodies in auto-immune peripheral nerve hyperexcitability syndromes (PNHS) are directed against CASPR2 and LGI1, proteins of the voltage-gated potassium channel (VGKC) complex. We discuss the significance of 'double-negative' VGKC antibodies in PNHS and the rationale for ceasing VGKC antibody testing (but testing CASPR2 and LGI1 antibodies instead) in clinical practice. Recent case reports also expand the possible clinical phenotypes related to CASPR2/LGI1 antibodies, but the interpretation of these findings is complicated by the frequent association of antibody-mediated neuromuscular hyperexcitability syndromes with other auto-immune disorders (e.g. myasthenia gravis).Finally, a hereditary origin of neuromuscular hyperexcitability should always be considered, even in non-VGKC-related genes, as evidenced by the recently discovered high frequency of HINT1 mutations in people of Slavic origin. SUMMARY This review provides an update on recent clinical, immunological and genetic developments in neuromuscular hyperexcitability syndromes. We also provide a guide for the clinician for diagnosing and managing these disorders in clinical practice, with a special focus on the main differential diagnoses.
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The Neuromuscular Junction: Roles in Aging and Neuromuscular Disease. Int J Mol Sci 2021; 22:ijms22158058. [PMID: 34360831 PMCID: PMC8347593 DOI: 10.3390/ijms22158058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that bridges the motor neuron and the skeletal muscle fiber and is crucial for conversion of electrical impulses originating in the motor neuron to action potentials in the muscle fiber. The consideration of contributing factors to skeletal muscle injury, muscular dystrophy and sarcopenia cannot be restricted only to processes intrinsic to the muscle, as data show that these conditions incur denervation-like findings, such as fragmented NMJ morphology and corresponding functional changes in neuromuscular transmission. Primary defects in the NMJ also influence functional loss in motor neuron disease, congenital myasthenic syndromes and myasthenia gravis, resulting in skeletal muscle weakness and heightened fatigue. Such findings underscore the role that the NMJ plays in neuromuscular performance. Regardless of cause or effect, functional denervation is now an accepted consequence of sarcopenia and muscle disease. In this short review, we provide an overview of the pathologic etiology, symptoms, and therapeutic strategies related to the NMJ. In particular, we examine the role of the NMJ as a disease modifier and a potential therapeutic target in neuromuscular injury and disease.
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10
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Howard JF, Bril V, Vu T, Karam C, Peric S, Margania T, Murai H, Bilinska M, Shakarishvili R, Smilowski M, Guglietta A, Ulrichts P, Vangeneugden T, Utsugisawa K, Verschuuren J, Mantegazza R. Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial. Lancet Neurol 2021; 20:526-536. [PMID: 34146511 DOI: 10.1016/s1474-4422(21)00159-9] [Citation(s) in RCA: 175] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/23/2021] [Accepted: 05/10/2021] [Indexed: 11/15/2022]
Abstract
BACKGROUND There is an unmet need for treatment options for generalised myasthenia gravis that are effective, targeted, well tolerated, and can be used in a broad population of patients. We aimed to assess the safety and efficacy of efgartigimod (ARGX-113), a human IgG1 antibody Fc fragment engineered to reduce pathogenic IgG autoantibody levels, in patients with generalised myasthenia gravis. METHODS ADAPT was a randomised, double-blind, placebo-controlled, phase 3 trial done at 56 neuromuscular academic and community centres in 15 countries in North America, Europe, and Japan. Patients aged at least 18 years with generalised myasthenia gravis were eligible to participate in the study, regardless of anti-acetylcholine receptor antibody status, if they had a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of at least 5 (>50% non-ocular), and were on a stable dose of at least one treatment for generalised myasthenia gravis. Patients were randomly assigned by interactive response technology (1:1) to efgartigimod (10 mg/kg) or matching placebo, administered as four infusions per cycle (one infusion per week), repeated as needed depending on clinical response no sooner than 8 weeks after initiation of the previous cycle. Patients, investigators, and clinical site staff were all masked to treatment allocation. The primary endpoint was proportion of acetylcholine receptor antibody-positive patients who were MG-ADL responders (≥2-point MG-ADL improvement sustained for ≥4 weeks) in the first treatment cycle. The primary analysis was done in the modified intention-to-treat population of all acetylcholine receptor antibody-positive patients who had a valid baseline MG-ADL assessment and at least one post-baseline MG-ADL assessment. The safety analysis included all randomly assigned patients who received at least one dose or part dose of efgartigimod or placebo. This trial is registered at ClinicalTrials.gov (NCT03669588); an open-label extension is ongoing (ADAPT+, NCT03770403). FINDINGS Between Sept 5, 2018, and Nov 26, 2019, 167 patients (84 in the efgartigimod group and 83 in the placebo group) were enrolled, randomly assigned, and treated. 129 (77%) were acetylcholine receptor antibody-positive. Of these patients, more of those in the efgartigimod group were MG-ADL responders (44 [68%] of 65) in cycle 1 than in the placebo group (19 [30%] of 64), with an odds ratio of 4·95 (95% CI 2·21-11·53, p<0·0001). 65 (77%) of 84 patients in the efgartigimod group and 70 (84%) of 83 in the placebo group had treatment-emergent adverse events, with the most frequent being headache (efgartigimod 24 [29%] vs placebo 23 [28%]) and nasopharyngitis (efgartigimod ten [12%] vs placebo 15 [18%]). Four (5%) efgartigimod-treated patients and seven (8%) patients in the placebo group had a serious adverse event. Three patients in each treatment group (4%) discontinued treatment during the study. There were no deaths. INTERPRETATION Efgartigimod was well tolerated and efficacious in patients with generalised myasthenia gravis. The individualised dosing based on clinical response was a unique feature of ADAPT, and translation to clinical practice with longer term safety and efficacy data will be further informed by the ongoing open-label extension. FUNDING argenx.
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Affiliation(s)
- James F Howard
- Department of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Vera Bril
- Ellen & Martin Prosserman Centre for Neuromuscular Diseases, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Tuan Vu
- Department of Neurology, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Chafic Karam
- Penn Neuroscience Center-Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Stojan Peric
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Temur Margania
- Department of Neurology and Neurorehabilitation, New Hospitals, Tbilisi, Georgia
| | - Hiroyuki Murai
- Department of Neurology, School of Medicine, International University of Health and Welfare, Narita, Japan
| | - Malgorzata Bilinska
- Department and Clinic of Neurology, Wroclaw Medical University, Wroclaw, Poland
| | | | - Marek Smilowski
- Department of Hematology and Bone Marrow Transplantation, Medical University of Silesia, Katowice, Poland
| | | | | | | | | | - Jan Verschuuren
- Department of Neurology, Leiden University Medical Center, Leiden, Netherlands
| | - Renato Mantegazza
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
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11
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Gastaldi M, Scaranzin S, Businaro P, Mobilia E, Benedetti L, Pesce G, Franciotta D. Improving laboratory diagnostics in myasthenia gravis. Expert Rev Mol Diagn 2021; 21:579-590. [PMID: 33970749 DOI: 10.1080/14737159.2021.1927715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Myasthenia gravis (MG) is a prototypical autoimmune disease, characterized by pathogenic autoantibodies targeting structures of the neuromuscular junction. Radioimmunoprecipitation assays (RIPAs) represent the gold standard for their detection. However, new methods are emerging to complement, or overcome RIPAs, also with the perspective of eliminating the use of radioactive reagents.Areas covered: We discuss advances in laboratory methods, prompted especially by cell-based assays (CBAs), for the detection of the autoantibodies of MG diagnostics, above all those to the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low molecular-weight receptor-related low-density lipoprotein-4 (LRP4).Expert opinion: CBA technology makes AChRs aggregate on cell membranes, thus allowing to detect autoantibodies to clustered AChRs, with reduction of seronegative MG cases. The diagnostic relevance of RIPA/CBA-measurable LRP4 antibodies is still unclear, in Caucasian patients at least. Live CBAs for the detection of AChR, MuSK, and LRP4 antibodies might represent an alternative to RIPAs, but first require full validation. CBAs could be used as screening tests, limiting RIPAs for antibody quantification. To this end, ELISAs might be an alternative.Fixation procedures preserving enough degree of antigen conformationality could yield AChR and MuSK CBAs suitable for a wide use in clinical-chemistry laboratories.
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Affiliation(s)
- Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Silvia Scaranzin
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Pietro Businaro
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Emanuela Mobilia
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Luana Benedetti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Giampaola Pesce
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine (Dimi), University of Genova, Genova, Italy
| | - Diego Franciotta
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
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12
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Gastrointestinal dysfunction in neuroinflammatory diseases: Multiple sclerosis, neuromyelitis optica, acute autonomic ganglionopathy and related conditions. Auton Neurosci 2021; 232:102795. [PMID: 33740560 DOI: 10.1016/j.autneu.2021.102795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 01/25/2023]
Abstract
Disorders of the nervous system can produce a variety of gastrointestinal (GI) dysfunctions. Among these, lesions in various brain structures can cause appetite loss (hypothalamus), decreased peristalsis (presumably the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (presumably parabrachial nucleus/Kolliker-Fuse nucleus) and hiccupping and vomiting (area postrema/dorsal vagal complex). In addition, decreased peristalsis with/without loss of bowel sensation can be caused by lesions of the spinal long tracts and the intermediolateral nucleus or of the peripheral nerves and myenteric plexus. Recently, neural diseases of inflammatory etiology, particularly those affecting the PNS, are being recognized to contribute to GI dysfunction. Here, we review neuroinflammatory diseases that potentially cause GI dysfunction. Among such CNS diseases are multiple sclerosis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein associated disorder, and autoimmune encephalitis. Peripheral nervous system diseases impacting the gut include Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, acute sensory-autonomic neuropathy/acute motor-sensory-autonomic neuropathy, acute autonomic ganglionopathy, myasthenia gravis and acute autonomic neuropathy with paraneoplastic syndrome. Finally, collagen diseases, such as Sjogren syndrome and systemic sclerosis, and celiac disease affect both CNS and PNS. These neuro-associated GI dysfunctions may predate or present concurrently with brain, spinal cord or peripheral nerve dysfunction. Such patients may visit gastroenterologists or physicians first, before the neurological diagnosis is made. Therefore, awareness of these phenomena among general practitioners and collaboration between gastroenterologists and neurologists are highly recommended in order for their early diagnosis and optimal management, as well as for systematic documentation of their presentations and treatment.
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13
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Paz ML, Barrantes FJ. Cholesterol in myasthenia gravis. Arch Biochem Biophys 2021; 701:108788. [PMID: 33548213 DOI: 10.1016/j.abb.2021.108788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 01/13/2021] [Accepted: 01/26/2021] [Indexed: 01/03/2023]
Abstract
The cholinergic neuromuscular junction is the paradigm peripheral synapse between a motor neuron nerve ending and a skeletal muscle fiber. In vertebrates, acetylcholine is released from the presynaptic site and binds to the nicotinic acetylcholine receptor at the postsynaptic membrane. A variety of pathologies among which myasthenia gravis stands out can impact on this rapid and efficient signaling mechanism, including autoimmune diseases affecting the nicotinic receptor or other synaptic proteins. Cholesterol is an essential component of biomembranes and is particularly rich at the postsynaptic membrane, where it interacts with and modulates many properties of the nicotinic receptor. The profound changes inflicted by myasthenia gravis on the postsynaptic membrane necessarily involve cholesterol. This review analyzes some aspects of myasthenia gravis pathophysiology and associated postsynaptic membrane dysfunction, including dysregulation of cholesterol metabolism in the myocyte brought about by antibody-receptor interactions. In addition, given the extensive therapeutic use of statins as the typical cholesterol-lowering drugs, we discuss their effects on skeletal muscle and the possible implications for MG patients under chronic treatment with this type of compound.
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Affiliation(s)
- Mariela L Paz
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Inmunología, Buenos Aires, Argentina; CONICET, Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral "Prof. Dr. Ricardo A. Margni" (IDEHU), Buenos Aires, Argentina
| | - Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute (BIOMED), UCA, CONICET, Av. Alicia Moreau de Justo 1600, C1107AFF, Buenos Aires, Argentina.
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Zou A, Ramanathan S, Dale RC, Brilot F. Single-cell approaches to investigate B cells and antibodies in autoimmune neurological disorders. Cell Mol Immunol 2021; 18:294-306. [PMID: 32728203 PMCID: PMC8027387 DOI: 10.1038/s41423-020-0510-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/07/2020] [Indexed: 12/18/2022] Open
Abstract
Autoimmune neurological disorders, including neuromyelitis optica spectrum disorder, anti-N-methyl-D-aspartate receptor encephalitis, anti-MOG antibody-associated disorders, and myasthenia gravis, are clearly defined by the presence of autoantibodies against neurological antigens. Although these autoantibodies have been heavily studied for their biological activities, given the heterogeneity of polyclonal patient samples, the characteristics of a single antibody cannot be definitively assigned. This review details the findings of polyclonal serum and CSF studies and then explores the advances made by single-cell technologies to the field of antibody-mediated neurological disorders. High-resolution single-cell methods have revealed abnormalities in the tolerance mechanisms of several disorders and provided further insight into the B cells responsible for autoantibody production. Ultimately, several factors, including epitope specificity and binding affinity, finely regulate the pathogenic potential of an autoantibody, and a deeper appreciation of these factors may progress the development of targeted immunotherapies for patients.
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Affiliation(s)
- Alicia Zou
- Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research at the Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Sudarshini Ramanathan
- Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research at the Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Russell C Dale
- Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research at the Children's Hospital at Westmead, Sydney, NSW, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
| | - Fabienne Brilot
- Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research at the Children's Hospital at Westmead, Sydney, NSW, Australia.
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
- Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia.
- School of Medical Sciences, Discipline of Applied Medical Science, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
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15
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Marcuse F, Hochstenbag M, Hoeijmakers JGJ, Hamid MA, Damoiseaux J, Maessen J, De Baets M. Subclinical myasthenia gravis in thymomas. Lung Cancer 2020; 152:143-148. [PMID: 33401082 DOI: 10.1016/j.lungcan.2020.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/07/2020] [Accepted: 12/11/2020] [Indexed: 01/03/2023]
Abstract
BACKGROUND A proportion of thymoma-patients without a history of myasthenia gravis (MG) before thymectomy, appears to have positive anti-AChR-antibodies in the serum. These subclinical MG-patients could be underdiagnosed because analyzation of anti-AChR-antibodies in thymomas is not always performed in patients who did not experience neurological symptoms. The prevalence and long-term outcomes of subclinical MG are never described in literature yet. METHODS We retrospectively analyzed 398 consecutive patients who underwent a robotic-assisted thoracoscopic surgery at the Maastricht University Medical Center+ (MUMC+) between April 2004 and December 2018. In the MUMC+, a robotic approach is the standard surgical approach in patients with thymic diseases. Inclusion criteria were thymomas, thymectomy performed in the MUMC + with a follow-up of at least one year and age above 18 years old. Exclusion criteria were patients with thymic carcinomas, refused participation, or those who were lost to follow-up. RESULTS Of the 102 included thymoma-patients, 87 patients (85 %) were tested for anti-AChR-antibodies before thymectomy, of which 57 patients were diagnosed with clinical MG and seven subclinical MG-patients were found. Of the 15 patients who were not tested for anti-AChR-antibodies, four more subclinical MG-patients were discovered in the years after thymectomy. The median follow-up time was 62 months. In total, 11 subclinical MG-patients were found, with a mean age of 54 years and predominantly females (64 %). Ten subclinical MG-patients (91 %) developed clinical-MG, within six years after thymectomy. Immunosuppressive drugs were prescribed in five patients. Four patients were diagnosed with a recurrence of the thymoma. No surgical mortality was reported. Two patients died due to a myasthenic crisis. CONCLUSIONS The prevalence of subclinical MG in thymomas was found to be 10.8 %. One in four patients who experienced no neurological symptoms before thymectomy, appeared to have anti-AChR-antibodies and 91 % of these patients developed clinical MG within six years after the thymectomy. Analyzing anti-AChR-antibodies in the serum is recommended in all suspected thymomas before a thymectomy is performed.
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Affiliation(s)
- Florit Marcuse
- Department of Pulmonology, Maastricht University Medical Center+, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Monique Hochstenbag
- Department of Pulmonology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Janneke G J Hoeijmakers
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Myrurgia Abdul Hamid
- Department of Pathology, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Jan Damoiseaux
- Central Diagnostic Laboratory, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Jos Maessen
- Department of Cardiothoracic Surgery, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Marc De Baets
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
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16
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Rodríguez Cruz PM, Cossins J, Beeson D, Vincent A. The Neuromuscular Junction in Health and Disease: Molecular Mechanisms Governing Synaptic Formation and Homeostasis. Front Mol Neurosci 2020; 13:610964. [PMID: 33343299 PMCID: PMC7744297 DOI: 10.3389/fnmol.2020.610964] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers. On arrival of the motor nerve action potential, calcium enters the presynaptic terminal, which leads to the release of the neurotransmitter acetylcholine (ACh). ACh crosses the synaptic gap and binds to ACh receptors (AChRs) tightly clustered on the surface of the muscle fiber; this leads to the endplate potential which initiates the muscle action potential that results in muscle contraction. This is a simplified version of the events in neuromuscular transmission that take place within milliseconds, and are dependent on a tiny but highly structured NMJ. Much of this review is devoted to describing in more detail the development, maturation, maintenance and regeneration of the NMJ, but first we describe briefly the most important molecules involved and the conditions that affect their numbers and function. Most important clinically worldwide, are myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS), each of which causes specific molecular defects. In addition, we mention the neurotoxins from bacteria, snakes and many other species that interfere with neuromuscular transmission and cause potentially fatal diseases, but have also provided useful probes for investigating neuromuscular transmission. There are also changes in NMJ structure and function in motor neuron disease, spinal muscle atrophy and sarcopenia that are likely to be secondary but might provide treatment targets. The NMJ is one of the best studied and most disease-prone synapses in the nervous system and it is amenable to in vivo and ex vivo investigation and to systemic therapies that can help restore normal function.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Judith Cossins
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
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Nagaishi A, Narita T, Woodhall M, Jacobson L, Waters P, Irani SR, Vincent A, Matsuo H. Autoantibodies in Japanese patients with ocular myasthenia gravis. Muscle Nerve 2020; 63:262-267. [PMID: 33094484 PMCID: PMC7983878 DOI: 10.1002/mus.27103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 10/14/2020] [Accepted: 10/18/2020] [Indexed: 12/16/2022]
Abstract
Introduction The majority of patients with myasthenia gravis (MG) initially present with ocular symptoms, but it is difficult to predict which cases will remain as ocular MG (OMG) or will progress to generalized MG. Herein we evaluated the serologic profile of Japanese OMG and its relationship with clinical features. Methods Seventy‐three patients with OMG from five Japanese myasthenia gravis (MG) centers were enrolled. Live cell‐based assays (CBAs) were used to determine the presence of autoantibodies (Abs) to clustered adult (2α, β, δ, ε) and fetal (2α, β, δ, γ) acetylcholine receptor (AChR) isoforms, muscle‐specific receptor tyrosine kinase (MuSK), and lipoprotein receptor–related protein‐4 (LRP4). Results Thirty‐four of 73 (46.5%) serum samples were positive for Abs against both the adult‐type and fetal‐type AChR, as expected, but 7 (9.6%) and 2 (2.7%) were positive only for fetal or adult AChR‐Abs, respectively. Four (5.4%) samples were positive for MuSK‐Abs, but two of these also contained antibodies to fetal AChR or LRP4. Twenty‐six (35.6%) samples were seronegative. Discussion Abs against fetal‐specific AChR, MuSK, and LRP4 are found in some patients with OMG. Future studies attempting to predict conversion from ocular symptoms to generalized MG may benefit from measurement of these antibodies.
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Affiliation(s)
- Akiko Nagaishi
- Department of Neurology, Nagasaki Kawatana Medical Center, Nagasaki, Japan.,Nuffield Department of Clinical Neurosciences, Oxford Autoimmune Neurology Group, University of Oxford, Oxford, UK
| | - Tomoko Narita
- Department of Neurology, Nagasaki Kawatana Medical Center, Nagasaki, Japan
| | - Mark Woodhall
- Nuffield Department of Clinical Neurosciences, Oxford Autoimmune Neurology Group, University of Oxford, Oxford, UK
| | - Leslie Jacobson
- Nuffield Department of Clinical Neurosciences, Oxford Autoimmune Neurology Group, University of Oxford, Oxford, UK
| | - Patrick Waters
- Nuffield Department of Clinical Neurosciences, Oxford Autoimmune Neurology Group, University of Oxford, Oxford, UK
| | - Sarosh R Irani
- Nuffield Department of Clinical Neurosciences, Oxford Autoimmune Neurology Group, University of Oxford, Oxford, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Hidenori Matsuo
- Department of Neurology, Nagasaki Kawatana Medical Center, Nagasaki, Japan
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