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Pavlekovics M, Engh MA, Lugosi K, Szabo L, Hegyi P, Terebessy T, Csukly G, Molnar Z, Illes Z, Lovas G. Plasma Exchange versus Intravenous Immunoglobulin in Worsening Myasthenia Gravis: A Systematic Review and Meta-Analysis with Special Attention to Faster Relapse Control. Biomedicines 2023; 11:3180. [PMID: 38137401 PMCID: PMC10740589 DOI: 10.3390/biomedicines11123180] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 11/21/2023] [Accepted: 11/25/2023] [Indexed: 12/24/2023] Open
Abstract
Currently used rescue interventions to prevent rapid myasthenic deterioration are plasma exchange (PLEX) and intravenous immunoglobulin (IVIG). We investigated the evidence to determine whether the two methods were interchangeable or whether one was superior to the other. This review was registered on PROSPERO (CRD42021285985). Only randomized controlled trials (RCTs) comparing the efficacy and safety of PLEX and IVIG in patients with moderate-to-severe myasthenia gravis (MG) were included. Five major databases were systematically searched (PubMed, CENTRAL, Embase, Scopus, and Web of Science). Odds ratios (OR) with 95% confidence intervals (CI) were calculated for adverse events and mean differences (MD) for changes in quantitative myasthenia gravis scores (QMG). Three RCTs met the inclusion criteria. Two investigating 114 patients in total were eligible for meta-analysis to analyze efficacy and safety. For the change in QMG score, the MD was -2.8 (95% CI: -5.614-0.113), with PLEX performing better. For adverse events, an OR of 1.04 was found (95% CI: 0.25-4.27). This study demonstrated a low risk of bias in evaluating treatment efficacy but indicated a high risk of bias in assessing procedural safety outcomes. Although the results did not show any significant difference, there was a tendency indicating faster efficacy of PLEX in the first two weeks of treatment. In such a critical clinical condition, this tendency may be clinically meaningful, but further studies should clarify this benefit.
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Affiliation(s)
- Mark Pavlekovics
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Neurology, Jahn Ferenc Teaching Hospital, Köves út 1, 1204 Budapest, Hungary
| | - Marie Anne Engh
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
| | - Katalin Lugosi
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Neurology, Bajcsy-Zsilinszky Hospital, Maglódi út 89–91, 1106 Budapest, Hungary
| | - Laszlo Szabo
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
| | - Peter Hegyi
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Institute of Pancreatic Diseases, Semmelweis University, Baross utca 22–24, 1085 Budapest, Hungary
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti Street, 7623 Pécs, Hungary
| | - Tamas Terebessy
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Orthopedics, Semmelweis University, Üllői út 78/b, 1082 Budapest, Hungary
| | - Gabor Csukly
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Psychiatry and Psychotherapy, Semmelweis University, Balassa utca 6, 1083 Budapest, Hungary
| | - Zsolt Molnar
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Anesthesiology and Intensive Therapy, Semmelweis University, 78 Üllöi St, 1085 Budapest, Hungary
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Winslows Vej 4, 5000 Odense, Denmark
- Institute of Clinical Research, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Gabor Lovas
- Center for Translational Medicine, Semmelweis University, Üllöi út 26, 1085 Budapest, Hungary; (M.P.)
- Department of Neurology, Jahn Ferenc Teaching Hospital, Köves út 1, 1204 Budapest, Hungary
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Gracey C, Balladares R. Symptoms of Myasthenia Gravis Obscured by Old Age and Unilateral Presentation. Cureus 2023; 15:e44737. [PMID: 37809196 PMCID: PMC10555472 DOI: 10.7759/cureus.44737] [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] [Accepted: 09/03/2023] [Indexed: 10/10/2023] Open
Abstract
Myasthenia gravis (MG) is a neuromuscular junction disorder involving autoantibodies affecting the postsynaptic muscle membrane. We report an 81-year-old man who presented to the emergency department with three days of left facial droop, who later developed worsening bilateral ptosis, cervical weakness, dysphagia, and dysarthria following an assessment for Bell's palsy. Ultimately, he was diagnosed with MG. This patient's presentation was atypical and challenging. Specifically, the patient had droopy eyelids from a redundancy of skin and an anatomical neck droop, non-specific findings in older adults, which obscured the development of bilateral ptosis and cervical weakness, a classic sign of bulbar disease. The patient also presented with unilateral facial weakness, a rare finding in MG and concerning stroke in the elderly population. Our aim is to discuss the challenges of identifying MG in older populations and to discuss pharmacological challenges in assessing elderly patients with suspected bulbar palsies.
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Affiliation(s)
- Celeste Gracey
- Internal Medicine, Campbell University School of Osteopathic Medicine, Lillington, USA
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Le Tanno P, Latypova X, Rendu J, Fauré J, Bourg V, Gauthier M, Billy-Lopez G, Jouk PS, Dieterich K. Diagnostic workup in children with arthrogryposis: description of practices from a single reference centre, comparison with literature and suggestion of recommendations. J Med Genet 2023; 60:13-24. [PMID: 34876503 DOI: 10.1136/jmedgenet-2021-107823] [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: 03/02/2021] [Accepted: 11/18/2021] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Arthrogryposis multiplex congenita (AMC) refers to a clinical presentation of congenital contractures involving two or more body areas. More than 400 distinct conditions may lead to AMC, making the aetiological diagnosis challenging. The objective of this work was to set up evidence-based recommendations for the diagnosis of AMC by taking advantage of both data from our nation-wide cohort of children with AMC and from the literature. MATERIAL AND METHODS We conducted a retrospective single-centre observational study. Patients had been evaluated at least once at a paediatric age in the AMC clinic of Grenoble University Hospital between 2007 and 2019. After gathering data about their diagnostic procedure, a literature review was performed for each paraclinical investigation to discuss their relevance. RESULTS One hundred and twenty-five patients were included, 43% had Amyoplasia, 27% had distal arthrogryposis and 30% had other forms. A definitive aetiological diagnosis was available for 66% of cases. We recommend a two-time diagnostic process: first, non-invasive investigations that aim at classifying patients into one of the three groups, and second, selected investigations targeting a subset of patients. CONCLUSION The aetiological management for patients with AMC remains arduous. This process will be facilitated by the increasing use of next-generation sequencing combined with detailed phenotyping. Invasive investigations should be avoided because of their limited yield.
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Affiliation(s)
- Pauline Le Tanno
- Univ. Grenoble Alpes, Inserm, U1209, CHU Grenoble Alpes, Institut of Advanced Biosciences, 38000 Grenoble, France
| | - Xenia Latypova
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institute of Neurosciences, 38000 Grenoble, France
| | - John Rendu
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institute of Neurosciences, 38000 Grenoble, France
| | - Julien Fauré
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institute of Neurosciences, 38000 Grenoble, France
| | - Véronique Bourg
- Service de Médecine Physique et Réhabilitation pédiatrique, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Marjolaine Gauthier
- Service de Génétique, Génomique et Procréation, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Gipsy Billy-Lopez
- Service de Génétique, Génomique et Procréation, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Pierre-Simon Jouk
- Service de Génétique, Génomique et Procréation, CHU Grenoble Alpes, 38000 Grenoble, France
| | - Klaus Dieterich
- Univ. Grenoble Alpes, Inserm, U1209, CHU Grenoble Alpes, Institut of Advanced Biosciences, 38000 Grenoble, France
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Treatment and Management of Disorders of the Neuromuscular Junction. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00019-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Cimpoca-Raptis BA, Ciobanu AM, Gica N, Peltecu G, Mitrea D, Panaitescu AM. Fetal Surveillance in Pregnancies with Myasthenia Gravis. Medicina (B Aires) 2021; 57:medicina57111277. [PMID: 34833495 PMCID: PMC8624595 DOI: 10.3390/medicina57111277] [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: 10/05/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune condition, that commonly impacts adult women of reproductive age. Myasthenia gravis in pregnancy is rare, but the incidence is higher in different geographical areas. Pregnancies in mothers with MG can have an unfortunate outcome. Acetylcholine receptor antibodies may pass into the fetal circulation and can affect the fetal neuromuscular junction, generating transient MG or even fetal arthrogryposis. The 2016 and 2021 International Consensus Guidance for Management of Myasthenia Gravis issued by Myasthenia Gravis Foundation of America is lacking in recommendation for fetal surveillance for pregnancies in women with MG. The aim of this paper is to highlight fetal and neonatal complications in mothers with MG and to offer antenatal care insights. Close maternal and pregnancy monitoring can improve pregnancy outcome. Patients with MG should be encouraged to conceive, to avoid triggers for exacerbations of the disease during pregnancy and a multidisciplinary team should be established to ensure the optimal support and therapy.
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Affiliation(s)
- Brîndușa Ana Cimpoca-Raptis
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.A.C.-R.); (N.G.); (G.P.); (A.M.P.)
- Filantropia Clinical Hospital, 011132 Bucharest, Romania
| | - Anca Marina Ciobanu
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.A.C.-R.); (N.G.); (G.P.); (A.M.P.)
- Filantropia Clinical Hospital, 011132 Bucharest, Romania
- Correspondence:
| | - Nicolae Gica
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.A.C.-R.); (N.G.); (G.P.); (A.M.P.)
- Filantropia Clinical Hospital, 011132 Bucharest, Romania
| | - Gheorghe Peltecu
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.A.C.-R.); (N.G.); (G.P.); (A.M.P.)
- Filantropia Clinical Hospital, 011132 Bucharest, Romania
| | - Dan Mitrea
- Neuroaxis, Neurology Clinic, 011302 Bucharest, Romania;
| | - Anca Maria Panaitescu
- Department of Obstetrics and Gynecology, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.A.C.-R.); (N.G.); (G.P.); (A.M.P.)
- Filantropia Clinical Hospital, 011132 Bucharest, Romania
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Siddiqi ZA, Nowak RJ, Mozaffar T, O'Brien F, Yountz M, Patti F. Eculizumab in refractory generalized myasthenia gravis previously treated with rituximab: subgroup analysis of REGAIN and its extension study. Muscle Nerve 2021; 64:662-669. [PMID: 34590717 DOI: 10.1002/mus.27422] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 12/24/2022]
Abstract
INTRODUCTION/AIMS Individuals with refractory generalized myasthenia gravis (gMG) who have a history of rituximab use and experience persistent symptoms represent a population with unmet treatment needs. The aim of this analysis was to evaluate the efficacy and safety of eculizumab in patients with refractory anti-acetylcholine receptor antibody-positive (AChR+ ) gMG previously treated with rituximab. METHODS This post hoc subgroup analysis of the phase 3 REGAIN study (NCT01997229) and its open-label extension (OLE; NCT02301624) compared baseline characteristics, safety, and response to eculizumab in participants who had previously received rituximab with those who had not. Rituximab use was not permitted within the 6 months before screening or during REGAIN/OLE. RESULTS Of 125 REGAIN participants, 14 had received rituximab previously (7 received placebo and 7 received eculizumab). In the previous-rituximab group, 57% had used at least four other immunosuppressants compared with 16% in the no-previous-rituximab group. Myasthenia Gravis Activities of Daily Living total scores from eculizumab baseline to week 130 of eculizumab treatment improved in both the previous-rituximab and no-previous-rituximab groups (least-squares mean -4.4, standard error of the mean [SEM] 1.0 [n = 9] and least-squares mean -4.6, SEM 0.3 [n = 67], respectively; difference = 0.2, 95% confidence interval -1.88 to 2.22). In addition, in both groups, most patients who were treated with eculizumab for 130 weeks achieved a Myasthenia Gravis Foundation of America post-intervention status of minimal manifestations (66.7% and 65.0%, respectively). The eculizumab safety profile was similar between groups and consistent with its established profile. DISCUSSION Eculizumab is an effective therapy for patients with refractory AChR+ gMG, irrespective of whether they had received rituximab treatment previously.
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Affiliation(s)
- Zaeem A Siddiqi
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Richard J Nowak
- Department of Neurology, Yale University School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Tahseen Mozaffar
- Department of Neurology, University of California Irvine, Orange, California, USA
| | - Fanny O'Brien
- Alexion Pharmaceuticals, Inc., Boston, Massachusetts, USA
| | - Marcus Yountz
- Alexion Pharmaceuticals, Inc., Boston, Massachusetts, USA
| | - Francesco Patti
- Department of Medical and Surgical Sciences and Advanced Technologies, G.F. Ingrassia, University of Catania, Catania, Italy
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Heleno CT, Mustafa A, Gotera NA, Tesar A. Myasthenia Gravis as an Immune-Mediated Side Effect of Checkpoint Inhibitors. Cureus 2021; 13:e16316. [PMID: 34277306 PMCID: PMC8275066 DOI: 10.7759/cureus.16316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2021] [Indexed: 11/05/2022] Open
Abstract
This is a case report of new-onset myasthenia gravis (MG) as an immune-mediated adverse event (irAE) related to the use of pembrolizumab in a patient with undifferentiated adenocarcinoma of the pancreato-biliary tract. Up to this moment, only 52 cases of new-onset MG have been related to immune checkpoint inhibitors (ICIs). She was diagnosed with ocular MG nearly three months after starting the use of the anti-programmed death-ligand 1 (PD-1) inhibitor. The diagnosis was confirmed by the presence of serum antibodies against the acetylcholine receptor and the patient was started on pyridostigmine with subsequent clinical improvement. The use of pembrolizumab was discontinued due to concomitant progression of the subjacent malignant disease.
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Affiliation(s)
- Caio T Heleno
- Internal Medicine, MercyOne North Iowa Medical Center, Mason City, USA
| | - Ala Mustafa
- Internal Medicine, MercyOne North Iowa Medical Center, Mason City, USA
| | - Nico A Gotera
- Internal Medicine, MercyOne North Iowa Medical Center, Mason City, USA
| | - Amy Tesar
- Internal Medicine, MercyOne North Iowa Medical Center, Mason City, USA
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Sanadze AG, Gilvanova OV. [Myasthenia gravis and muscle atrophy]. Zh Nevrol Psikhiatr Im S S Korsakova 2021; 121:79-87. [PMID: 33728855 DOI: 10.17116/jnevro202112102179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Muscle atrophy is uncommon in myasthenia gravis. There are some reports in the literature of muscle atrophy in MUSK-positive myasthenia gravis. The authors present eight cases of AChR-positive myasthenia gravis associated with muscle atrophy. Symmetrical atrophy of the forearms with preserved hand muscles was identified in six cases and scapular winging in two cases. Atrophy appeared 3-18 years after the onset of myasthenia gravis and after a period of progression, the condition was stabilized. In all cases, there were no pain syndrome, no sensory loss, normal creatine phosphokinase (CPK) levels, no significant abnormality on MRI of the cervical spine. Concomitant neuropathies, amyotrophic lateral sclerosis and other neuromuscular diseases were excluded. All patients underwent quantitative electromyography and repetitive nerve stimulation. The authors suggest that the atrophy is not the sign of myasthenia gravis in this case and is caused by other neuromuscular diseases.
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Affiliation(s)
- A G Sanadze
- Moscow Myasthenic Center of the City Clinical Hospital No. 51, Moscow, Russia
| | - O V Gilvanova
- Moscow Myasthenic Center of the City Clinical Hospital No. 51, Moscow, Russia
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Ciobanu AM, Dumitru AE, Gica N, Botezatu R, Peltecu G, Panaitescu AM. Benefits and Risks of IgG Transplacental Transfer. Diagnostics (Basel) 2020; 10:E583. [PMID: 32806663 PMCID: PMC7459488 DOI: 10.3390/diagnostics10080583] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/07/2020] [Accepted: 08/10/2020] [Indexed: 12/13/2022] Open
Abstract
Maternal passage of immunoglobulin G (IgG) is an important passive mechanism for protecting the infant while the neonatal immune system is still immature and ineffective. IgG is the only antibody class capable of crossing the histological layers of the placenta by attaching to the neonatal Fc receptor expressed at the level of syncytiotrophoblasts, and it offers protection against neonatal infectious pathogens. In pregnant women with autoimmune or alloimmune disorders, or in those requiring certain types of biological therapy, transplacental passage of abnormal antibodies may cause fetal or neonatal harm. In this review, we will discuss the physiological mechanisms and benefits of transplacental transfer of maternal antibodies as well as pathological maternal situations where this system is hijacked, potentially leading to adverse neonatal outcomes.
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Affiliation(s)
- Anca Marina Ciobanu
- Carol Davila University of Medicine and Pharmacy, Bucharest 020021, Romania; (A.M.C.); (N.G.); (R.B.); (G.P.)
- Filantropia Clinical Hospital, Bucharest 11171, Romania;
| | | | - Nicolae Gica
- Carol Davila University of Medicine and Pharmacy, Bucharest 020021, Romania; (A.M.C.); (N.G.); (R.B.); (G.P.)
- Filantropia Clinical Hospital, Bucharest 11171, Romania;
| | - Radu Botezatu
- Carol Davila University of Medicine and Pharmacy, Bucharest 020021, Romania; (A.M.C.); (N.G.); (R.B.); (G.P.)
- Filantropia Clinical Hospital, Bucharest 11171, Romania;
| | - Gheorghe Peltecu
- Carol Davila University of Medicine and Pharmacy, Bucharest 020021, Romania; (A.M.C.); (N.G.); (R.B.); (G.P.)
- Filantropia Clinical Hospital, Bucharest 11171, Romania;
| | - Anca Maria Panaitescu
- Carol Davila University of Medicine and Pharmacy, Bucharest 020021, Romania; (A.M.C.); (N.G.); (R.B.); (G.P.)
- Filantropia Clinical Hospital, Bucharest 11171, Romania;
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Aguirre F, Manin A, Fernandez VC, Justo ME, Leoni J, Paz ML, Villa AM. C3, C5a and anti-acetylcholine receptor antibody as severity biomarkers in myasthenia gravis. Ther Adv Neurol Disord 2020; 13:1756286420935697. [PMID: 32843900 PMCID: PMC7418469 DOI: 10.1177/1756286420935697] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 05/12/2020] [Indexed: 12/16/2022] Open
Abstract
Background Although the pathogenesis of myasthenia gravis (MG) is well known, prognostic markers are not yet available. We assessed the utility of anti-acetylcholine receptor (AChR) antibody (AChR-ab) titer and concentration of C3, C4, and C5a as potential severity biomarkers in MG. Methods Levels of C3, C4, C5a, and AChR-ab were measured in 60 AChR-ab-positive patients with MG. Their relationship with clinical severity was analyzed using the activities of daily living (ADL) and MG composite (MGC) scales. Results AChR-ab titer correlated with severity of MG according to ADL (p = 0.002) and MGC scales (p = 0.001). When patients were classified according to disease duration, a statistically significant correlation between AChR-ab titer and clinical severity was only found in the subgroup of patients with fewer than 5 years from symptoms onset. C5a levels showed a positive correlation with MG severity according to the ADL scale (p = 0.041; τb = 0.18), although C5a levels were not different from the control group. Discussion AChR-ab titers and C5a levels could potentially be considered markers of severity in patients with MG.
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Affiliation(s)
- Florencia Aguirre
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Analisa Manin
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Victoria C Fernandez
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Mariano E Justo
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología. CONICET - Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Juliana Leoni
- CONICET - Universidad de Buenos Aires, Instituto de Estudios de la, Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Mariela L Paz
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología. CONICET - Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Andres M Villa
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
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Mantegazza R, O'Brien FL, Yountz M, Howard JF. Consistent improvement with eculizumab across muscle groups in myasthenia gravis. Ann Clin Transl Neurol 2020; 7:1327-1339. [PMID: 32700461 PMCID: PMC7448154 DOI: 10.1002/acn3.51121] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/10/2020] [Accepted: 06/10/2020] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE To assess whether eculizumab, a terminal complement inhibitor, improves patient- and physician-reported outcomes (evaluated using the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale, respectively) in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis across four domains, representing ocular, bulbar, respiratory, and limb/gross motor muscle groups. METHODS Patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis were randomized 1:1 to receive either placebo or eculizumab during the REGAIN study (NCT01997229). Patients who completed REGAIN were eligible to continue into the open-label extension trial (NCT02301624) for up to 4 years. The four domain scores of each of the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale recorded throughout REGAIN and through 130 weeks of the open-label extension were analyzed. RESULTS Of the 125 patients who participated in REGAIN, 117 enrolled in the open-label extension; 61 had received placebo and 56 had received eculizumab during REGAIN. Patients experienced rapid improvements in total scores and all four domain scores of both the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale with eculizumab treatment. These improvements were sustained through 130 weeks of the open-label extension. INTERPRETATION Eculizumab treatment elicits rapid and sustained improvements in muscle strength across ocular, bulbar, respiratory, and limb/gross motor muscle groups and in associated daily activities in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis.
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Affiliation(s)
- Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases UnitFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | | | | | - James F. Howard
- Department of NeurologyUniversity of North CarolinaChapel HillNC
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Affiliation(s)
| | - Sheebu V Chacko
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX
| | - Shabana Yusuf
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX
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A novel MuSK cell-based myasthenia gravis diagnostic assay. J Neuroimmunol 2019; 337:577076. [PMID: 31655425 DOI: 10.1016/j.jneuroim.2019.577076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 10/25/2022]
Abstract
To improve the clinical diagnosis of neural autoimmune diseases, we developed an in-house muscle-specific kinase (MuSK) antibody cell-based assay (CBA) and compared its performance with RIA, ELISA, and other CBAs. Sera from patients with myasthenia gravis (MG) and other autoimmune diseases were analyzed. We found 46 (18.3%) MuSK-CBA Ab positive cases among 251 AChR-Ab negative cases [patients] and 4 (0.6%) MuSK-CBA Ab positive cases [among] the 624 AChR-Ab positive samples. Comparing these with available clinic assays, our highly specific CBA method is more sensitive than commercial ELISA and IFA(indirect immunofluorescence assay).
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Abstract
This article discusses antibodies associated with immune-mediated myasthenia gravis and the pathologic action of these antibodies at the neuromuscular junctions of skeletal muscle. To explain how these antibodies act, we consider the physiology of neuromuscular transmission with emphasis on 4 features: the structure of the neuromuscular junction; the roles of postsynaptic acetylcholine receptors and voltage-gated Na+ channels and in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber that triggers muscle contraction; the safety factor for neuromuscular transmission; and how the safety factor is reduced in different forms of autoimmune myasthenia gravis.
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Affiliation(s)
- Robert L Ruff
- Department of Neurology, Case Western University School of Medicine, The Metro Health System, 2500 Metro Health Drive, Cleveland, OH 44109, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Robert P Lisak
- Department of Neurology, Wayne State University School of Medicine, 8D University Health Center, 4201 St Antoine, Detroit, MI 48201, USA; Department of Biochemistry, Microbiology and Immunology, Wayne State University, Detroit, MI, USA.
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15
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Generalized Weakness in the Neurocritical Care Unit. Neurocrit Care 2019. [DOI: 10.1017/9781107587908.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Mané-Damas M, Hoffmann C, Zong S, Tan A, Molenaar PC, Losen M, Martinez-Martinez P. Autoimmunity in psychotic disorders. Where we stand, challenges and opportunities. Autoimmun Rev 2019; 18:102348. [PMID: 31323365 DOI: 10.1016/j.autrev.2019.102348] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 02/26/2019] [Indexed: 12/24/2022]
Abstract
Psychotic disorders are debilitating mental illnesses associated with abnormalities in various neurotransmitter systems. The development of disease-modifing therapies has been hampered by the mostly unknown etiologies and pathophysiologies. Autoantibodies against several neuronal antigens are responsible for autoimmune encephalitis. These autoantibodies disrupt neurotransmission within the brain, resulting in a wide range of psychiatric and neurologic manifestations, including psychosis. The overlap of symptoms of autoimmune encephalitis with psychotic disorders raised the question as to whether autoantibodies against a number of receptors, ion channel and associated proteins could ultimately be responsible for some forms of psychosis. Here we review our current knowledge, on antibody mediated autoimmunity in psychotic disorders, the different diagnostic methods and their limitations, as well as on varying therapeutic approaches targeting the immune system.
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Affiliation(s)
- Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Carolin Hoffmann
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Shenghua Zong
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Amanda Tan
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
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17
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Muppidi S, Utsugisawa K, Benatar M, Murai H, Barohn RJ, Illa I, Jacob S, Vissing J, Burns TM, Kissel JT, Nowak RJ, Andersen H, Casasnovas C, de Bleecker JL, Vu TH, Mantegazza R, O'Brien FL, Wang JJ, Fujita KP, Howard JF. Long-term safety and efficacy of eculizumab in generalized myasthenia gravis. Muscle Nerve 2019; 60:14-24. [PMID: 30767274 PMCID: PMC6619057 DOI: 10.1002/mus.26447] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2019] [Indexed: 01/16/2023]
Abstract
Introduction: Eculizumab is effective and well tolerated in patients with antiacetylcholine receptor antibody‐positive refractory generalized myasthenia gravis (gMG; REGAIN; NCT01997229). We report an interim analysis of an open‐label extension of REGAIN, evaluating eculizumab's long‐term safety and efficacy. Methods: Eculizumab (1,200 mg every 2 weeks for 22.7 months [median]) was administered to 117 patients. Results: The safety profile of eculizumab was consistent with REGAIN; no cases of meningococcal infection were reported during the interim analysis period. Myasthenia gravis exacerbation rate was reduced by 75% from the year before REGAIN (P < 0.0001). Improvements with eculizumab in activities of daily living, muscle strength, functional ability, and quality of life in REGAIN were maintained through 3 years; 56% of patients achieved minimal manifestations or pharmacological remission. Patients who had received placebo during REGAIN experienced rapid and sustained improvements during open‐label eculizumab (P < 0.0001). Discussion: These findings provide evidence for the long‐term safety and sustained efficacy of eculizumab for refractory gMG. Muscle Nerve 2019 See editorial on pages 7–9 in this issue.
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Affiliation(s)
- Srikanth Muppidi
- Department of Neurology and Neurosciences, Stanford University School of Medicine, Stanford, California, USA
| | | | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Hiroyuki Murai
- Department of Neurology, International University of Health and Welfare, Narita, Japan
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Isabel Illa
- Neurology Department, Hospital Sant Pau, Autonomous University of Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain
| | - Saiju Jacob
- Queen Elizabeth Neuroscience Centre and Wellcome Trust Clinical Research Facility, University Hospital Birmingham, Birmingham, United Kingdom
| | - John Vissing
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ted M Burns
- Department of Neurology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - John T Kissel
- Department of Neurology, The Ohio State University, Columbus, Ohio, USA
| | - Richard J Nowak
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Henning Andersen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Carlos Casasnovas
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain.,Department of Neurology, Bellvitge University Hospital, Barcelona, Spain
| | - Jan L de Bleecker
- Neuromuscular Reference Centre, Ghent University Hospital, Ghent, Belgium
| | - Tuan H Vu
- Department of Neurology, University of South Florida, Tampa, Florida, USA
| | - Renato Mantegazza
- Foundation of the Carlo Besta Neurological Institute, IRCSS, Milan, Italy
| | | | | | | | - James F Howard
- Department of Neurology, University of North Carolina, Chapel Hill, North Carolina, USA
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18
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Howard JF, Utsugisawa K, Benatar M, Murai H, Barohn RJ, Illa I, Jacob S, Vissing J, Burns TM, Kissel JT, Muppidi S, Nowak RJ, O'Brien F, Wang JJ, Mantegazza R. Safety and efficacy of eculizumab in anti-acetylcholine receptor antibody-positive refractory generalised myasthenia gravis (REGAIN): a phase 3, randomised, double-blind, placebo-controlled, multicentre study. Lancet Neurol 2017; 16:976-986. [PMID: 29066163 DOI: 10.1016/s1474-4422(17)30369-1] [Citation(s) in RCA: 422] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 01/30/2023]
Abstract
BACKGROUND Complement is likely to have a role in refractory generalised myasthenia gravis, but no approved therapies specifically target this system. Results from a phase 2 study suggested that eculizumab, a terminal complement inhibitor, produced clinically meaningful improvements in patients with anti-acetylcholine receptor antibody-positive refractory generalised myasthenia gravis. We further assessed the efficacy and safety of eculizumab in this patient population in a phase 3 trial. METHODS We did a phase 3, randomised, double-blind, placebo-controlled, multicentre study (REGAIN) in 76 hospitals and specialised clinics in 17 countries across North America, Latin America, Europe, and Asia. Eligible patients were aged at least 18 years, with a Myasthenia Gravis-Activities of Daily Living (MG-ADL) score of 6 or more, Myasthenia Gravis Foundation of America (MGFA) class II-IV disease, vaccination against Neisseria meningitides, and previous treatment with at least two immunosuppressive therapies or one immunosuppressive therapy and chronic intravenous immunoglobulin or plasma exchange for 12 months without symptom control. Patients with a history of thymoma or thymic neoplasms, thymectomy within 12 months before screening, or use of intravenous immunoglobulin or plasma exchange within 4 weeks before randomisation, or rituximab within 6 months before screening, were excluded. We randomly assigned participants (1:1) to either intravenous eculizumab or intravenous matched placebo for 26 weeks. Dosing for eculizumab was 900 mg on day 1 and at weeks 1, 2, and 3; 1200 mg at week 4; and 1200 mg given every second week thereafter as maintenance dosing. Randomisation was done centrally with an interactive voice or web-response system with patients stratified to one of four groups based on MGFA disease classification. Where possible, patients were maintained on existing myasthenia gravis therapies and rescue medication was allowed at the study physician's discretion. Patients, investigators, staff, and outcome assessors were masked to treatment assignment. The primary efficacy endpoint was the change from baseline to week 26 in MG-ADL total score measured by worst-rank ANCOVA. The efficacy population set was defined as all patients randomly assigned to treatment groups who received at least one dose of study drug, had a valid baseline MG-ADL assessment, and at least one post-baseline MG-ADL assessment. The safety analyses included all randomly assigned patients who received eculizumab or placebo. This trial is registered with ClinicalTrials.gov, number NCT01997229. FINDINGS Between April 30, 2014, and Feb 19, 2016, we randomly assigned and treated 125 patients, 62 with eculizumab and 63 with placebo. The primary analysis showed no significant difference between eculizumab and placebo (least-squares mean rank 56·6 [SEM 4·5] vs 68·3 [4·5]; rank-based treatment difference -11·7, 95% CI -24·3 to 0·96; p=0·0698). No deaths or cases of meningococcal infection occurred during the study. The most common adverse events in both groups were headache and upper respiratory tract infection (ten [16%] for both events in the eculizumab group and 12 [19%] for both in the placebo group). Myasthenia gravis exacerbations were reported by six (10%) patients in the eculizumab group and 15 (24%) in the placebo group. Six (10%) patients in the eculizumab group and 12 (19%) in the placebo group required rescue therapy. INTERPRETATION The change in the MG-ADL score was not statistically significant between eculizumab and placebo, as measured by the worst-rank analysis. Eculizumab was well tolerated. The use of a worst-rank analytical approach proved to be an important limitation of this study since the secondary and sensitivity analyses results were inconsistent with the primary endpoint result; further research into the role of complement is needed. FUNDING Alexion Pharmaceuticals.
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Affiliation(s)
- James F Howard
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA.
| | | | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hiroyuki Murai
- Department of Neurology, International University of Health and Welfare, Narita, Japan
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, KA, USA
| | - Isabel Illa
- Neurology Department, Hospital Sant Pau, Universitat Autònoma Barcelona, Barcelona, Spain
| | - Saiju Jacob
- Queen Elizabeth Neuroscience Centre, Wellcome Trust Clinical Research Facility, University Hospitals of Birmingham, Birmingham, UK
| | - John Vissing
- Rigshospitalet, Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Ted M Burns
- Department of Neurology, University of Virginia Health System, Charlottesville, VA, USA
| | - John T Kissel
- Department of Neurology, Ohio State University, Columbus, OH, USA
| | - Srikanth Muppidi
- Department of Neurology and Neurosciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Richard J Nowak
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
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19
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Abstract
Maternal autoantibodies can cross the placenta and cause fetal damage. This article summarizes the development and management of fetal thyroid goiter in response to maternal Graves' disease and/or its treatment with antithyroid medication, fetal heart block due to maternal anti-Ro and anti-La antibodies, fetal athrogryposis multiplex congenita in association with maternal myasthenia gravis and fetal brain hemorrhage due to maternal autoimmune thrombocytopenia.
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Affiliation(s)
| | - Kypros Nicolaides
- a Fetal Medicine Research Institute , King's College Hospital , London , UK
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20
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Ueta R, Tezuka T, Izawa Y, Miyoshi S, Nagatoishi S, Tsumoto K, Yamanashi Y. The carboxyl-terminal region of Dok-7 plays a key, but not essential, role in activation of muscle-specific receptor kinase MuSK and neuromuscular synapse formation. J Biochem 2017; 161:269-277. [PMID: 28069867 DOI: 10.1093/jb/mvw073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 09/21/2016] [Indexed: 11/14/2022] Open
Abstract
As the synapse between a motor neuron and skeletal muscle, the neuromuscular junction (NMJ) is required for muscle contraction. The formation and maintenance of NMJs are controlled by the muscle-specific receptor kinase MuSK. Dok-7 is the essential cytoplasmic activator of MuSK, and indeed mice lacking Dok-7 form no NMJs. Moreover, DOK7 gene mutations underlie DOK7 myasthenia, an NMJ synaptopathy. Previously, we failed to detect MuSK activation in myotubes by Dok-7 mutated in the N-terminal pleckstrin homology (PH) or phosphotyrosine binding (PTB) domain or that lacked the C-terminal region (Dok-7-ΔC). Here, we found by quantitative analysis that Dok-7-ΔC marginally, but significantly, activated MuSK in myotubes, unlike the PH- or PTB-mutant. Purified, recombinant Dok-7-ΔC, but not other mutants, also showed marginal ability to activate MuSK's cytoplasmic portion, carrying the kinase domain. Consistently, forced expression of Dok-7-ΔC rescued Dok-7-deficient mice from neonatal lethality caused by the lack of NMJs, indicating restored MuSK activation and NMJ formation. However, these mice showed only marginal activation of MuSK and died by 3 weeks of age apparently due to an abnormally small number and size of NMJs. Thus, Dok-7's C-terminal region plays a key, but not fully essential, role in MuSK activation and NMJ formation.
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Affiliation(s)
- Ryo Ueta
- Division of Genetics, Department of Cancer Biology
| | - Tohru Tezuka
- Division of Genetics, Department of Cancer Biology
| | - Yosuke Izawa
- Division of Genetics, Department of Cancer Biology
| | | | - Satoru Nagatoishi
- Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.,Drug Discovery Initiative, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kouhei Tsumoto
- Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.,Drug Discovery Initiative, The University of Tokyo, Tokyo 113-0033, Japan.,Laboratory of Medical Proteomics, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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21
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Alipour-Faz A, Shojaei M, Peyvandi H, Ramzi D, Oroei M, Ghadiri F, Peyvandi M. A comparison between IVIG and plasma exchange as preparations before thymectomy in myasthenia gravis patients. Acta Neurol Belg 2017; 117:245-249. [PMID: 27530310 DOI: 10.1007/s13760-016-0689-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 08/05/2016] [Indexed: 10/21/2022]
Abstract
Myasthenia gravis (MG) is one of the curable neurologic disorders. Various pharmacological therapies are administered for these patients and a thymectomy plays an important role in the therapy of myasthenia gravis, which develops a permanent or relative remission. We investigated the efficacy of intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) as a preparation before thymectomy in patients with MG. This randomized clinical trial was conducted on 24 patients with MG referred for thymectomy, which were randomized to two groups of IVIG and PLEX. The IVIG group received IVIG 1 g/kg/day for two consecutive days and the PLEX group underwent 1-L plasma exchange five times with 5 % albumin replacement fluid, every other day, 10-30 days before the procedure. The duration of hospitalization (day), length of intensive care unit (ICU) stay after surgery (day), length of intubation period (h), duration of surgery (h) and dose of steroid administered were compared between the two groups. Analysis was performed via SPSS version 20. In the PLEX group, post-operative outcomes (duration of hospitalization, ICU length of stay after surgery, intubation period and duration of surgery) were longer than those in the IVIG group. There was significant difference in intubation period (p value = 0.01) and duration of surgery (p value = 0.05) between the PLEX and IVIG groups. The administration of IVIG in comparison to PLEX can be more effective in the preparation before thymectomy in myasthenia gravis patients.
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22
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Eguchi T, Tezuka T, Miyoshi S, Yamanashi Y. Postnatal knockdown of dok-7 gene expression in mice causes structural defects in neuromuscular synapses and myasthenic pathology. Genes Cells 2016; 21:670-6. [PMID: 27091576 DOI: 10.1111/gtc.12370] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 03/08/2016] [Indexed: 02/01/2023]
Abstract
The neuromuscular junction (NMJ) is a synapse between a motor neuron and skeletal muscle and is required for muscle contraction. The formation and maintenance of NMJs are governed by the muscle-specific receptor tyrosine kinase MuSK. We previously showed that the muscle cytoplasmic protein Dok-7 is an essential activator of MuSK. Indeed, mice lacking either Dok-7 or MuSK form no NMJs, and defects in the human DOK7 gene underlie a congenital myasthenic syndrome (an NMJ disorder). However, it remains unproven whether Dok-7 is required for the postnatal maintenance of NMJs. In this study, we generated recombinant adeno-associated virus (AAV) vectors encoding short hairpin RNAs targeting the mouse dok-7 gene (AAV-shD7). Systemic administration of AAV-shD7 into 2-week-old mice down-regulated dok-7 expression in muscle and induced myasthenic symptoms including reduction in body weight and motor function. Moreover, AAV-shD7 treatment suppressed MuSK-dependent gene expression of NMJ components and reduced the size of NMJs. These results demonstrate that correct, physiological levels of dok-7 expression are required for the postnatal maintenance of NMJs.
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Affiliation(s)
- Takahiro Eguchi
- Division of Genetics, Department of Cancer Biology, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Tohru Tezuka
- Division of Genetics, Department of Cancer Biology, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Sadanori Miyoshi
- Division of Genetics, Department of Cancer Biology, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Yuji Yamanashi
- Division of Genetics, Department of Cancer Biology, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
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23
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Bradl M, Lassmann H. Neurologic autoimmunity: mechanisms revealed by animal models. HANDBOOK OF CLINICAL NEUROLOGY 2016; 133:121-43. [PMID: 27112675 DOI: 10.1016/b978-0-444-63432-0.00008-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Over the last decade, neurologic autoimmunity has become a major consideration in the diagnosis and management of patients with many neurologic presentations. The nature of the associated antibodies and their targets has led to appreciation of the importance of the accessibility of the target antigen to antibodies, and a partial understanding of the different mechanisms that can follow antibody binding. This chapter will first describe the basic principles of autoimmune inflammation and tissue damage in the central and peripheral nervous system, and will then demonstrate what has been learnt about neurologic autoimmunity from circumstantial clinical evidence and from passive, active, and occasionally spontaneous or genetic animal models. It will cover neurologic autoimmune diseases ranging from disorders of neuromuscular transmission, peripheral and ganglionic neuropathy, to diseases of the central nervous system, where autoantibodies are either pathogenic and cause destruction or changes in function of their targets, where they are harmless bystanders of T-cell-mediated tissue damage, or are not involved at all. Finally, this chapter will summarize the relevance of current animal models for studying the different neurologic autoimmune diseases, and it will identify aspects where future animal models need to be improved to better reflect the disease reality experienced by affected patients, e.g., the chronicity or the relapsing/remitting nature of their disease.
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Affiliation(s)
- Monika Bradl
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, Vienna, Austria.
| | - Hans Lassmann
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, Vienna, Austria
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24
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Targeted killing of rhabdomyosarcoma cells by a MAP-based human cytolytic fusion protein. Cancer Lett 2015; 365:149-55. [PMID: 25888452 DOI: 10.1016/j.canlet.2015.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 04/02/2015] [Accepted: 04/04/2015] [Indexed: 12/26/2022]
Abstract
The treatment of rhabdomyosarcoma (RMS) is challenging, and the prognosis remains especially poor for high-grade RMS with metastasis. The conventional treatment of RMS is based on multi-agent chemotherapy combined with resection and radiotherapy, which are often marked by low success rate. Alternative therapeutic options include the combination of standard treatments with immunotherapy. We generated a microtubule-associated protein (MAP)-based fully human cytolytic fusion protein (hCFP) targeting the fetal acetylcholine receptor, which is expressed on RMS cells. We were able to express and purify functional scFv35-MAP from Escherichia coli cells. Moreover, we found that scFv35-MAP is rapidly internalized by target cells after binding its receptor, and exhibits specific cytotoxicity toward FL-OH1 and RD cells in vitro. We also confirmed that scFv35-MAP induces apoptosis in FL-OH1 and RD cells. The in vivo potential of scFv35-MAP will need to be considered in further studies.
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25
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Yilmaz V, Oflazer P, Aysal F, Parman YG, Direskeneli H, Deymeer F, Saruhan-Direskeneli G. B cells produce less IL-10, IL-6 and TNF-α in myasthenia gravis. Autoimmunity 2014; 48:201-7. [PMID: 25518708 DOI: 10.3109/08916934.2014.992517] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
B cells from myasthenia gravis (MG) patients with autoantibodies (Aab) against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or with no detectable Aab were investigated as cytokine producing cells in this study. B cells were evaluated for memory phenotypes and expressions of IL-10, IL-6 and IL-12A. Induced productions of IL-10, IL-6, IL-12p40, TNF-α and LT from isolated B cells in vitro were measured by immunoassays. MG patients receiving immunosuppressive treatment had higher proportions of memory B cells compared with healthy controls and untreated patients. With CD40 stimulation MG patients produced significantly lower levels of IL-10, IL-6. With CD40 and B cell receptor stimulation of B cells, TNF-α production also decreased in addition to these cytokines. The lower levels of these cytokine productions were not related to treatment. Our results confirm a disturbance of B cell subpopulations in MG subgroups on immunosuppressive treatment. B cell derived IL-10, IL-6 and TNF-α are down-regulated in MG, irrespective of different antibody productions. Ineffective cytokine production by B cells may be a susceptibility factor in dysregulation of autoimmune Aab production.
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26
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Vrinten C, van der Zwaag AM, Weinreich SS, Scholten RJPM, Verschuuren JJGM. Ephedrine for myasthenia gravis, neonatal myasthenia and the congenital myasthenic syndromes. Cochrane Database Syst Rev 2014; 2014:CD010028. [PMID: 25515947 PMCID: PMC7387729 DOI: 10.1002/14651858.cd010028.pub2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Myasthenia is a condition in which neuromuscular transmission is affected by antibodies against neuromuscular junction components (autoimmune myasthenia gravis, MG; and neonatal myasthenia gravis, NMG) or by defects in genes for neuromuscular junction proteins (congenital myasthenic syndromes, CMSs). Clinically, some individuals seem to benefit from treatment with ephedrine, but its effects and adverse effects have not been systematically evaluated. OBJECTIVES To assess the effects and adverse effects of ephedrine in people with autoimmune MG, transient neonatal MG, and the congenital myasthenic syndromes. SEARCH METHODS On 17 November 2014, we searched the Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. We also searched reference lists of articles, conference proceedings of relevant conferences, and prospective trial registers. In addition, we contacted manufacturers and researchers in the field. SELECTION CRITERIA We considered randomised controlled trials (RCTs) and quasi-RCTs comparing ephedrine as a single or add-on treatment with any other active treatment, placebo, or no treatment in adults or children with autoimmune MG, NMG, or CMSs. DATA COLLECTION AND ANALYSIS Two review authors independently assessed study design and quality, and extracted data. We contacted study authors for additional information. We collected information on adverse effects from included articles, and contacted authors. MAIN RESULTS We found no RCTs or quasi-RCTs, and therefore could not establish the effect of ephedrine on MG, NMG and CMSs. We describe the results of 53 non-randomised studies narratively in the Discussion section, including observations of endurance, muscle strength and quality of life. Effects may differ depending on the type of myasthenia. Thirty-seven studies were in participants with CMS, five in participants with MG, and in 11 the precise form of myasthenia was unknown. We found no studies for NMG. Reported adverse effects included tachycardia, sleep disturbances, nervousness, and withdrawal symptoms. AUTHORS' CONCLUSIONS There was no evidence available from RCTs or quasi-RCTs, but some observations from non-randomised studies are available. There is a need for more evidence from suitable forms of prospective RCTs, such as series of n-of-one RCTs, that use appropriate and validated outcome measures.
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Affiliation(s)
- Charlotte Vrinten
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Angeli M van der Zwaag
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Stephanie S Weinreich
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Rob JPM Scholten
- Julius Center for Health Sciences and Primary Care / University Medical Center UtrechtDutch Cochrane CentreRoom Str. 6.126P.O. Box 85500UtrechtNetherlands3508 GA
| | - Jan JGM Verschuuren
- Leiden University Medical CenterDepartment of NeurologyPO Box 9600LeidenNetherlands2300 RC
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27
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The MuSK activator agrin has a separate role essential for postnatal maintenance of neuromuscular synapses. Proc Natl Acad Sci U S A 2014; 111:16556-61. [PMID: 25368159 DOI: 10.1073/pnas.1408409111] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The motoneural control of skeletal muscle contraction requires the neuromuscular junction (NMJ), a midmuscle synapse between the motor nerve and myotube. The formation and maintenance of NMJs are orchestrated by the muscle-specific receptor tyrosine kinase (MuSK). Motor neuron-derived agrin activates MuSK via binding to MuSK's coreceptor Lrp4, and genetic defects in agrin underlie a congenital myasthenic syndrome (an NMJ disorder). However, MuSK-dependent postsynaptic differentiation of NMJs occurs in the absence of a motor neuron, indicating a need for nerve/agrin-independent MuSK activation. We previously identified the muscle protein Dok-7 as an essential activator of MuSK. Although NMJ formation requires agrin under physiological conditions, it is dispensable for NMJ formation experimentally in the absence of the neurotransmitter acetylcholine, which inhibits postsynaptic specialization. Thus, it was hypothesized that MuSK needs agrin together with Lrp4 and Dok-7 to achieve sufficient activation to surmount inhibition by acetylcholine. Here, we show that forced expression of Dok-7 in muscle enhanced MuSK activation in mice lacking agrin or Lrp4 and restored midmuscle NMJ formation in agrin-deficient mice, but not in Lrp4-deficient mice, probably due to the loss of Lrp4-dependent presynaptic differentiation. However, these NMJs in agrin-deficient mice rapidly disappeared after birth, and postsynaptic specializations emerged ectopically throughout myotubes whereas exogenous Dok-7-mediated MuSK activation was maintained. These findings demonstrate that the MuSK activator agrin plays another role essential for the postnatal maintenance, but not for embryonic formation, of NMJs and also for the postnatal, but not prenatal, midmuscle localization of postsynaptic specializations, providing physiological and pathophysiological insight into NMJ homeostasis.
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Alabdali M, Barnett C, Katzberg H, Breiner A, Bril V. Intravenous immunoglobulin as treatment for myasthenia gravis: current evidence and outcomes. Expert Rev Clin Immunol 2014; 10:1659-65. [PMID: 25331319 DOI: 10.1586/1744666x.2014.971757] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We examined the current evidence for the efficacy of IV immunoglobulin (IVIG) in myasthenia gravis (MG) and the outcomes used to demonstrate this efficacy. There is class 1 evidence for the use of short-term IVIG in MG patients worsening MG and also good evidence for IVIG use in myasthenic crisis. For long-term maintenance therapy, controlled studies are lacking and the evidence is limited to class III retrospective studies. The clinical scales, serological, electrophysiological, and patient-reported quality of life outcomes with IVIG have been assessed. At this time, the quantitative myasthenia gravis score, a functional scale, remains the preferable outcome measure as it has demonstrated responsiveness in the clinical trial setting, but a scale incorporating patient-reported outcomes and the patients complaint of fatigue is likely to be preferable. The MG-composite is such a scale, but has measurement limitations that may reduce its sensitivity. Across trials, IVIG has generally been well tolerated.
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Affiliation(s)
- Majed Alabdali
- Division of Neurology, Department of Medicine, Toronto General Hospital, University Health Network, University of Toronto, 200 Elizabeth St, Toronto, Ontario, M5A 4H9, Canada
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29
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Martinez-Martinez P, Molenaar PC, Losen M, Stevens J, Baets MHD, Szoke A, Honnorat J, Tamouza R, Leboyer M, Os JV, Rutten BPF. Autoantibodies to neurotransmitter receptors and ion channels: from neuromuscular to neuropsychiatric disorders. Front Genet 2013; 4:181. [PMID: 24065983 PMCID: PMC3778371 DOI: 10.3389/fgene.2013.00181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/27/2013] [Indexed: 01/17/2023] Open
Abstract
Changes of voltage-gated ion channels and ligand-gated receptor channels caused by mutation or autoimmune attack are the cause of so-called channelopathies in the central and peripheral nervous system. We present the pathophysiology of channelopathies of the neuromuscular junction in terms of loss-of-function and gain-of-function principles. Autoantibodies generally have reduced access to the central nervous system, but in some cases this is enough to cause disease. A review is provided of recent findings implicating autoantibodies against ligand-activated receptor channels and potassium channels in psychiatric and neurological disorders, including schizophrenia and limbic encephalitis. The emergence of channelopathy-related neuropsychiatric disorders has implications for research and practice.
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Affiliation(s)
- Pilar Martinez-Martinez
- Department of Psychiatry and Psychology, School for Mental Health and Neuroscience, Maastricht University Maastricht, Netherlands
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Leon-Sarmiento FE, Leon-Ariza DS, Doty RL. Dysfunctional chemosensation in myasthenia gravis: a systematic review. J Clin Neuromuscul Dis 2013; 15:1-6. [PMID: 23965402 DOI: 10.1097/cnd.0b013e31829e22ba] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVES Myasthenia gravis has traditionally been viewed as a disorder that solely affects the neuromuscular junction within the peripheral nervous system. However, there is now evidence that the cholinergic dysfunction of this disorder may be more widespread than previously believed. This article provides a systematic review of the studies that examined smell and taste function in myasthenia gravis. METHODS We analyzed studies that reported chemosensory function alterations in patients with myasthenia gravis. PubMed, MEDLINE, Web of Science, EMBASE, and SciELO, searched to identify articles published from January 1950 through December 2012, were supplemented by relevant articles. The following information was identified from each article: the number of patients, number of controls (if any), clinical stage of patients, neurological involvement, serological state, taste or smell involvement, chemosensory test used, and country of publication. RESULTS Ten studies reporting smell and taste function and dysfunction in patients with myasthenia gravis were identified, most of which were case reports commenting on apparent abnormalities in the taste system. The sole empirical study that investigated taste function, however, was negative, suggesting that some reports of taste loss may reflect olfactory loss. One study clearly documented olfactory dysfunction in patients with myasthenia gravis, dysfunction most likely attributable to altered central nervous system cholinergic function. CONCLUSIONS Chemosensory dysfunction has been reported in a number of patients with myasthenia gravis. Given the close association between complaints of taste dysfunction and loss of flavor sensations secondary to olfactory system damage, quantitative testing should be used to accurately assess the nature and degree of the dysfunction present in this debilitating disorder.
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Affiliation(s)
- Fidias E Leon-Sarmiento
- Smell and Taste Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Structure and activation of MuSK, a receptor tyrosine kinase central to neuromuscular junction formation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2166-9. [PMID: 23467009 DOI: 10.1016/j.bbapap.2013.02.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/22/2013] [Indexed: 01/09/2023]
Abstract
MuSK (muscle-specific kinase) is a receptor tyrosine kinase that plays a central signaling role in the formation of neuromuscular junctions (NMJs). MuSK is activated in a complex spatio-temporal manner to cluster acetylcholine receptors on the postsynaptic (muscle) side of the synapse and to induce differentiation of the nerve terminal on the presynaptic side. The ligand for MuSK is LRP4 (low-density lipoprotein receptor-related protein-4), a transmembrane protein in muscle, whose binding affinity for MuSK is potentiated by agrin, a neuronally derived heparan-sulfate proteoglycan. In addition, Dok7, a cytoplasmic adaptor protein, is also required for MuSK activation in vivo. This review focuses on the physical interplay between these proteins and MuSK for activation and downstream signaling, which culminates in NMJ formation. This article is part of a Special Issue entitled: Emerging recognition and activation mechanisms of receptor tyrosine kinases.
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Koneczny I, Cossins J, Vincent A. The role of muscle-specific tyrosine kinase (MuSK) and mystery of MuSK myasthenia gravis. J Anat 2013; 224:29-35. [PMID: 23458718 DOI: 10.1111/joa.12034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2013] [Indexed: 11/28/2022] Open
Abstract
MuSK myasthenia gravis is a rare, severe autoimmune disease of the neuromuscular junction, only identified in 2001, with unclear pathogenic mechanisms. In this review we describe the clinical aspects that distinguish MuSK MG from AChR MG, review what is known about the role of MuSK in the development and function of the neuromuscular junction, and discuss the data that address how the antibodies to MuSK lead to neuromuscular transmission failure.
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Affiliation(s)
- Inga Koneczny
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Bril V, Barnett-Tapia C, Barth D, Katzberg HD. IVIG and PLEX in the treatment of myasthenia gravis. Ann N Y Acad Sci 2012; 1275:1-6. [DOI: 10.1111/j.1749-6632.2012.06767.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Non-synonymous single nucleotide polymorphisms in genes for immunoregulatory galectins: association of galectin-8 (F19Y) occurrence with autoimmune diseases in a Caucasian population. Biochim Biophys Acta Gen Subj 2012; 1820:1512-8. [PMID: 22683700 DOI: 10.1016/j.bbagen.2012.05.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND Galectins are potent immune regulators, with galectin-8 acting as a pro-apoptotic effector on synovial fluid cells and thymocytes and stimulator on T-cells. To set a proof-of-principle example for risk assessment in autoimmunity, and for a mutation affecting physiological galectin sensor functions, a polymorphism in the coding region of the galectin-8 gene (rs2737713; F19Y) was studied for its association with two autoimmune disorders, i.e. rheumatoid arthritis and myasthenia gravis. METHODS A case-control analysis and a related quantitative trait-association study were performed to investigate the association of this polymorphism in patients (myasthenia gravis 149, rheumatoid arthritis 214 and 134 as primary and repetitive cohorts, respectively) and 365 ethnically matched (Caucasian) healthy controls. Distribution was also investigated in patients grouped according to their antibody status and age at disease onset. Comparative testing for lectin activity was carried out in ELISA/ELLA-based binding tests with both wild-type and F19Y mutant galectin-8 from peripheral blood mononuclear cell lysates of healthy individuals with different genotypes as well as with recombinant wild-type and F19Y mutant galectin-8 proteins. RESULTS A strong association was found for rheumatoid arthritis, and a mild one with myasthenia gravis. Furthermore, the presence of the sequence deviation also correlated with age at disease onset in the case of rheumatoid arthritis. The F19Y substitution did not appear to affect carbohydrate binding in solid-phase assays markedly. GENERAL SIGNIFICANCE This is the first report of an association between a galectin-based polymorphism leading to a mutant protein and autoimmune diseases, with evidence for antagonistic pleiotropy.
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35
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Hemminki K, Li X, Sundquist K. Familial Risks for Diseases of Myoneural Junction and Muscle in Siblings Based on Hospitalizations and Deaths in Sweden. Twin Res Hum Genet 2012. [DOI: 10.1375/twin.9.4.573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractDiseases of the myoneural junction and muscle are disabling and some are life-threatening. Recent successes in the identification of the underlying genetic mechanisms have had profound implication for their diagnostics, treatment and classification. We define familial risks for siblings who were hospitalized for or deceased from diseases of the myoneural junction and muscle. A nationwide database on diseases of the myoneural junction and muscle was constructed by linking the Multigeneration Register on 0- to 69-year-old siblings to the Hospital Discharge Register and the Causes of Death Register from years 1987 to 2001. Standardized risk ratios (SIRs) were calculated for affected sibling pairs by comparing to those whose siblings had no diseases of myoneural junction and muscle. Among a total of 2307 patients, myasthenia gravis, muscular dystrophy and myotonic disorders were commonest diagnoses. The sibling risks for these disease were 22, 190 and 198, respectively, when a sibling was diagnosed with any disease of the myoneural junction and muscle. The concordant SIRs, both siblings presenting the same disease, were 42 for myasthenia gravis, 737 for muscular dystrophy, 2000 for congenital myopathy, 1211 for myotonic disorder, 909 for periodic paralysis and 209 for unspecified myopathy. Only a few discordant sibling pairs were noted. The very high overall SIRs for the diseases of the myoneural junction and muscle imply that the sporadic forms of these diseases are relatively rare and these diseases are overwhelmingly heritable.
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Yamanashi Y, Tezuka T, Yokoyama K. Activation of receptor protein-tyrosine kinases from the cytoplasmic compartment. J Biochem 2012; 151:353-9. [PMID: 22343747 DOI: 10.1093/jb/mvs013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
It is widely accepted that receptor protein-tyrosine kinases (RTKs) are activated upon dimerization by binding to their extracellular ligands. However, EGF receptor (EGFR) dimerization per se does not require ligand binding. Instead, its cytoplasmic kinase domains have to form characteristic head-to-tail asymmetric dimers to become active, where one 'activator' domain activates the other 'receiver' domain. The non-catalytic, cytoplasmic regions of RTKs, namely the juxtamembrane and carboxy terminal portions, also regulate kinase activity. For instance, the juxtamembrane region of the RTK MuSK inhibits the kinase domain probably together with a cellular factor(s). These findings suggest that RTKs could be activated by cytoplasmic proteins. Indeed, Dok-7 and cytohesin have recently been identified as such activators of MuSK and EGFR, respectively. Given that failure of Dok-7 signaling causes myasthenia, and inhibition of cytohesin signaling reduces the proliferation of EGFR-dependent cancer cells, cytoplasmic activators of RTKs may provide new therapeutic targets.
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Affiliation(s)
- Yuji Yamanashi
- Division of Genetics, Department of Cancer Biology, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan.
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37
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Vrinten C, Weinreich SS, Scholten RJPM, Verschuuren JJGM. 3,4-Diaminopyridine for myasthenia gravis. Hippokratia 2012. [DOI: 10.1002/14651858.cd009675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Charlotte Vrinten
- VU University Medical Center; Community Genetics Section, Clinical Genetics; BS7, D420 PO Box 7057 1007 MB Amsterdam Netherlands
| | - Stephanie S. Weinreich
- VU University Medical Center; Community Genetics Section, Clinical Genetics; BS7, D420 PO Box 7057 1007 MB Amsterdam Netherlands
| | - Rob JPM Scholten
- Academic Medical Center; Dutch Cochrane Centre; Room J1B - 211 P.O. Box 22700 Amsterdam Netherlands 1100 DE
| | - Jan JGM Verschuuren
- Leiden University Medical Center; Department of Neurology; PO Box 9600 Leiden Netherlands 2300 RC
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38
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Ruff RL. Endplate contributions to the safety factor for neuromuscular transmission. Muscle Nerve 2011; 44:854-61. [DOI: 10.1002/mus.22177] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Serra A, Ruff R, Kaminski H, Leigh RJ. Factors contributing to failure of neuromuscular transmission in myasthenia gravis and the special case of the extraocular muscles. Ann N Y Acad Sci 2011; 1233:26-33. [DOI: 10.1111/j.1749-6632.2011.06123.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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40
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Barth D, Nabavi Nouri M, Ng E, Nwe P, Bril V. Comparison of IVIg and PLEX in patients with myasthenia gravis. Neurology 2011; 76:2017-23. [PMID: 21562253 PMCID: PMC3109880 DOI: 10.1212/wnl.0b013e31821e5505] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 02/18/2011] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Both IV immunoglobulin (IVIg) and plasma exchange (PLEX) are immunomodulatory treatments used to treat patients with myasthenia gravis (MG), but the choice of which treatment to administer to patients is limited due to lack of evidence from adequately powered, masked, randomized, standardized trials. METHODS We randomized 84 patients with moderate to severe MG defined as a Quantitative Myasthenia Gravis Score for disease severity (QMGS) of >10.5 and worsening weakness to IVIg (Gamunex®, Talecris Biotherapeutics) 1 g/kg/day for 2 consecutive days or PLEX (Caridian Spectra) 1.0 plasma volume exchanges for 5 exchanges. The patients were evaluated at day 14 after treatment for the primary efficacy parameter of change in QMGS and secondary clinical and electrophysiologic parameters and were followed for a total of 60 days. RESULTS Both IVIg and PLEX reduced the QMGS, and IVIg was comparable to PLEX in efficacy. The dropout rate was the same for both treatment arms and both treatments were well-tolerated. The presence of acetylcholine receptor antibodies and greater baseline disease severity predicted a better response to therapy. The postintervention status revealed that the same proportion of patients improved with treatment: 69% on IVIg and 65% on PLEX. The duration of improvement was similar with both treatments. CONCLUSIONS IVIg has comparable efficacy to PLEX in the treatment of patients with moderate to severe MG. Both treatments are well-tolerated, and the duration of effect is comparable. Either treatment may be offered to patients depending on availability of resources. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that IVIg and PLEX have comparable efficacy and are equally tolerated in adult patients with moderate to severe MG within 2 weeks of treatment.
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Affiliation(s)
- D Barth
- Department of Pathology, University Health Network, Toronto General Hospital, Toronto, Canada
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41
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Hamuro J, Hishida Y, Higuchi O, Yamanashi Y. The transcription factor Sp1 plays a crucial role in dok-7 gene expression. Biochem Biophys Res Commun 2011; 408:293-9. [DOI: 10.1016/j.bbrc.2011.04.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 04/05/2011] [Indexed: 11/27/2022]
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Abstract
The diagnostic use of antibodies is dependent on sensitivity and specificity of the methods of antibody detection, which have been developed and improved over the years. Here, we review the different methods for the detection of acetylcholine receptor and muscle-specific kinase antibodies, which are, so far, the only antibodies recognised as pathogenic in myasthenia gravis (MG). Seronegative MG patients will benefit from more sensitive methods of antibody detection. The most recent developments in antibody detection assays, particularly those based on cells expressing target antigens, allow rapid and reliable identification of autoantibodies, improving the diagnosis and treatment of MG patients. The same approaches to antibody detection are now being applied to a wide range of other autoantigens and other autoimmune diseases.
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Affiliation(s)
- M Isabel Leite
- Department of Clinical Neurology, John Radcliffe Hospital, University of Oxford, West Wing OX3 9DS, UK
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43
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Noninvasive Positive Airway Pressure in Hypercapnic Respiratory Failure in Noncardiac Medical Disorders. Sleep Med Clin 2010. [DOI: 10.1016/j.jsmc.2010.05.008] [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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44
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[Anti-NMDA-receptor encephalitis. An interdisciplinary clinical picture]. DER NERVENARZT 2010; 81:396, 398, 400, passim. [PMID: 20119656 DOI: 10.1007/s00115-009-2908-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Anti-NMDA-receptor encephalitis is a severe and considerably underdiagnosed form of encephalitis with characteristic clinical features including psychiatric symptoms, decreased levels of consciousness, hypoventilation, epileptic seizures, autonomic dysfunction and dyskinesias. Most patients are primarily seen by psychiatrists, often on the assumption of a drug-induced psychosis. Anti-NMDA-receptor encephalitis had initially been described in young women with ovarian teratoma, but is also common in women without tumour, in men and in children. The diagnosis is based on the characteristic clinical picture, supporting findings of brain MRI, electroencephalogram and cerebrospinal fluid (CSF), and the presence of highly specific autoantibodies directed against the NR1 subunit of NMDA-type glutamate receptors in the serum or CSF. In particular, anti-NMDA-receptor encephalitis must be excluded in patients with 'encephalitis of unknown cause'. In principle, the prognosis is favourable and recovery from symptoms can be expected even after prolonged intensive care treatment and mechanical ventilation. However, improvement correlates with prompt identification of the disorder, early immunotherapy and - in the case of a malignancy - with complete tumour removal. Patient care requires an interdisciplinary approach including neurologists, psychiatrists, paediatricians, oncologists and gynaecologists.
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Suhail H, Subbiah V, Singh S, Behari M. Serological and clinical features of patients with myasthenia gravis in north Indian population. Int J Neurosci 2010; 120:115-9. [PMID: 20199203 DOI: 10.3109/00207450903389131] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myasthenia gravis (MG) is a disorder of neuromuscular junction associated with presence of antibodies against nicotinic acetylcholine receptors (nAChRs). Here, we compared the clinical and serological profile of seropositive myasthenia gravis (SPMG) and seronegative myasthenia gravis (SNMG) patients. Anti-AChR antibody was measured using radio receptor immunoassay and correlated with clinical phenotype in 250 MG patients over 2004 and 2006. Out of 250 MG patients, 161 (64.4%) were males (male:female = 1.8:1). SNMG patients formed 40% (n = 101) of our MG patients which is much higher as compared to Caucasian and Oriental population (15%-20%). The median age of disease onset in SPMG was significantly higher than SNMG patients (43 years; range 8-74 vs. 35 years; range 4-72, p = .022). A bimodal peak of age of disease onset in both genders was observed (first peak in second-third decades and second one in fifth-sixth decades). Among the MG patients with late-onset of disease, male were significantly higher compared to Caucasian and Oriental MG population (p = .047). MG patients with thymoma were significantly older and consisted of higher percent of males. Bulbar symptoms and severe grade (IIB+ III+ IV) at disease onset were more frequent in SPMG than SNMG patients.
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Affiliation(s)
- Hamid Suhail
- Department of Neurology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
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Gattenlöhner S, Jörißen H, Huhn M, Vincent A, Beeson D, Tzartos S, Mamalaki A, Etschmann B, Muller-Hermelink HK, Koscielniak E, Barth S, Marx A. A human recombinant autoantibody-based immunotoxin specific for the fetal acetylcholine receptor inhibits rhabdomyosarcoma growth in vitro and in a murine transplantation model. J Biomed Biotechnol 2010; 2010:187621. [PMID: 20204062 PMCID: PMC2829619 DOI: 10.1155/2010/187621] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 11/18/2009] [Indexed: 11/28/2022] Open
Abstract
Rhabdomyosarcoma (RMS) is the most common malignant soft tissue tumor in children and is highly resistant to all forms of treatment currently available once metastasis or relapse has commenced. As it has recently been determined that the acetylcholine receptor (AChR) gamma-subunit, which defines the fetal AChR (fAChR) isoform, is almost exclusively expressed in RMS post partum, we recombinantly fused a single chain variable fragment (scFv) derived from a fully human anti-fAChR Fab-fragment to Pseudomonas exotoxin A to generate an anti-fAChR immunotoxin (scFv35-ETA). While scFv35-ETA had no damaging effect on fAChR-negative control cell lines, it killed human embryonic and alveolar RMS cell lines in vitro and delayed RMS development in a murine transplantation model. These results indicate that scFv35-ETA may be a valuable new therapeutic tool as well as a relevant step towards the development of a fully human immunotoxin directed against RMS. Moreover, as approximately 20% of metastatic malignant melanomas (MMs) display rhabdoid features including the expression of fAChR, the immunotoxin we developed may also prove to be of significant use in the treatment of these more common and most often fatal neoplasms.
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Affiliation(s)
- S. Gattenlöhner
- Institute of Pathology, University of Würzburg, 97080 Würzburg, Germany
| | - H. Jörißen
- Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstraße 6, 52074 Aachen, Germany
| | - M. Huhn
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DU Oxford, UK
| | - A. Vincent
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DU Oxford, UK
| | - D. Beeson
- Neurosciences Group, Department of Clinical Neurology, Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DU Oxford, UK
| | - S. Tzartos
- Hellenic Pasteur Institute, 127, Vas. Sofias Avenue 11521, Athens, Greece
| | - A. Mamalaki
- Hellenic Pasteur Institute, 127, Vas. Sofias Avenue 11521, Athens, Greece
| | - B. Etschmann
- Institute of Pathology, University of Würzburg, 97080 Würzburg, Germany
| | | | - E. Koscielniak
- Department of Pediatric Oncology, Olga Hospital, 70176 Stuttgart, Germany
| | - S. Barth
- Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstraße 6, 52074 Aachen, Germany
- Department of Experimental Medicine and Immunotherapy, Helmholtz-Institute for Biomedical Engineering, University Hospital RWTH Aachen, Pauwelsstraße 20, 52074 Aachen, Germany
| | - A. Marx
- Institute of Pathology, University of Würzburg, 97080 Würzburg, Germany
- Institute of Pathology, University Medical Center Mannheim, University of Heidelberg, Theodor-Kutzer Ufer 1-3, 68135 Mannheim, Greece
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Adhiyaman V, Black G. THE MAN WHO COULDN'T CLOSE HIS MOUTH. J Am Geriatr Soc 2010; 58:182. [DOI: 10.1111/j.1532-5415.2009.02638.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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ter Beek WP, Martínez-Martínez P, Losen M, de Baets MH, Wintzen AR, Verschuuren JJGM, Niks EH, van Duinen SG, Vincent A, Molenaar PC. The effect of plasma from muscle-specific tyrosine kinase myasthenia patients on regenerating endplates. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1536-44. [PMID: 19745065 DOI: 10.2353/ajpath.2009.090040] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Muscle-specific tyrosine kinase (MuSK) is essential for clustering of acetylcholine receptors (AChRs) at embryogenesis and likely also important for maintaining synaptic structure in adult muscle. In 5 to 7% of myasthenia gravis (MG) cases, the patients' blood contains antibodies to MuSK. To investigate the effect of MuSK-MG antibody on synapse regeneration, notexin was used to induce damage to the flexor digitorum brevis muscle. We administered aliquots of MuSK-MG patients' plasma to the flexor digitorum brevis twice daily for a period up to 21 days, and muscles were investigated ex vivo in contraction experiments. AChR levels were measured with (125)I-alpha-bungarotoxin, and endplates were studied with quantitative immunohistochemistry. In normal muscles and in 14-day regenerated muscles, MuSK plasma caused impairment of nerve stimulus-induced contraction in the presence of 0.35 and 0.5 mmol/L Ca(2+) with or without 100 to 400 nmol/L tubocurarine. Endplate size was decreased in regenerated muscles relative to controls; however, we did not observe such differences in muscle not treated with notexin. MuSK plasma had no effect on the amount and turnover rate of AChRs. Our results suggest that anti-MuSK antibodies influence the activity of MuSK molecules without reducing their number, thereby diminishing the size of the endplate and affecting the functioning of AChRs.
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Affiliation(s)
- W Pascale ter Beek
- Neurophysiology Section, Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
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Krishnan AV, Lin CSY, Park SB, Kiernan MC. Axonal ion channels from bench to bedside: a translational neuroscience perspective. Prog Neurobiol 2009; 89:288-313. [PMID: 19699774 DOI: 10.1016/j.pneurobio.2009.08.002] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/17/2009] [Accepted: 08/17/2009] [Indexed: 12/13/2022]
Abstract
Over recent decades, the development of specialised techniques such as patch clamping and site-directed mutagenesis have established the contribution of neuronal ion channel dysfunction to the pathophysiology of common neurological conditions including epilepsy, multiple sclerosis, spinal cord injury, peripheral neuropathy, episodic ataxia, amyotrophic lateral sclerosis and neuropathic pain. Recently, these insights from in vitro studies have been translated into the clinical realm. In keeping with this progress, novel clinical axonal excitability techniques have been developed to provide information related to the activity of a variety of ion channels, energy-dependent pumps and ion exchange processes activated during impulse conduction in peripheral axons. These non-invasive techniques have been extensively applied to the study of the biophysical properties of human peripheral nerves in vivo and have provided important insights into axonal ion channel function in health and disease. This review will provide a translational perspective, focusing on an overview of the investigational method, the clinical utility in assessing the biophysical basis of ectopic symptom generation in peripheral nerve disease and a review of the major findings of excitability studies in acquired and inherited neurological disease states.
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Affiliation(s)
- Arun V Krishnan
- Translational Neuroscience Facility, University of New South Wales, Randwick, Sydney, NSW, Australia
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Mössner R, Tings T, Beckmann I, Neumann C, Paulus W, Reich K. A close look at autoimmune muscle disorders: association of Lambert–Eaton myasthenic syndrome with dermatomyositis. Scand J Rheumatol 2009; 33:271-5. [PMID: 15370725 DOI: 10.1080/03009740410005476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Dermatomyositis/polymyositis (DM/PM) and Lambert-Eaton myasthenic syndrome (LEMS) are two autoimmune disorders that have very rarely been reported to occur together in the same patient. We report on two patients with DM who were later diagnosed with concomitant LEMS, and point out diagnostic challenges in identifying LEMS in patients with DM/PM. As specific treatment for LEMS is available, it is important to identify those DM/PM patients who suffer from concomitant LEMS.
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