1
|
Sorrenti B, Laurini C, Bosco L, Strano CMM, Scarlato M, Gastaldi M, Filippi M, Previtali SC, Falzone YM. Overcoming therapeutic challenges: Successful management of a supposedly triple seronegative, refractory generalized myasthenia gravis patient with efgartigimod. Eur J Neurol 2024; 31:e16306. [PMID: 38716750 PMCID: PMC11236002 DOI: 10.1111/ene.16306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 03/12/2024] [Accepted: 04/03/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND AND PURPOSE This study was undertaken to highlight neonatal Fc receptor inhibition (efgartigimod) as a valuable therapeutic option for patients with refractory seronegative myasthenia gravis (MG) and to emphasize the concept that seronegative MG is greatly constrained by the limitations of currently available diagnostic methods and therapeutic measures. METHODS We describe the first refractory, generalized MG (gMG) patient successfully treated with efgartigimod after testing negative on standard autoantibody detection tests. RESULTS Our patient presented with severe fluctuating bulbar and generalized weakness, resulting in multiple myasthenic crises requiring intubation. After a 28-year medical history of multiple failed lines of treatment, our patient was started on efgartigimod. Over five treatment cycles, a definite improvement in her clinical condition was observed (Myasthenia Gravis Foundation of America class: IIIb to IIb; MG-Activities of Daily Living score: 11 to 0; MG-Quality of Life 15 score: 30 to 0; Quantitative MG score: 28 to 6). Standard autoantibody detection tests failed to detect known pathogenic autoantibodies, but cell-based assay (CBA) identified autoantibodies against clustered adult acetylcholine receptor (AChR). CONCLUSIONS In light of recent approvals of efgartigimod by the European Medicines Agency and US Food and Drug Administration exclusively for AChR-positive gMG forms, our case highlights evidence suggesting that such an approach might be shortsighted and could limit therapeutic options for patients with refractory seronegative gMG. Additionally, introducing more sensitive analytical techniques, exemplified by CBA, may help bridge the gap between seronegative and seropositive patients. This represents an urgent unmet need for gMG patients, as the antibody profile dramatically influences the therapeutic approach.
Collapse
Affiliation(s)
| | | | - Luca Bosco
- Neuroimmunology Research UnitIRCCS Mondino FoundationPaviaItaly
- Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific InstituteMilanItaly
| | | | - Marina Scarlato
- Neurorehabilitation UnitQuarenghi Clinical InstituteSan Pellegrino Terme,Italy
| | - Matteo Gastaldi
- Neuroimmunology Research UnitIRCCS Mondino FoundationPaviaItaly
| | - Massimo Filippi
- Neuroimmunology Research UnitIRCCS Mondino FoundationPaviaItaly
- Vita‐Salute San Raffaele UniversityMilanItaly
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of NeuroscienceIRCCS San Raffaele Scientific InstituteMilanItaly
- Neurorehabilitation UnitIRCCS San Raffaele Scientific InstituteMilanItaly
- Neurophysiology ServiceIRCCS San Raffaele Scientific InstituteMilanItaly
| | - Stefano Carlo Previtali
- Neuroimmunology Research UnitIRCCS Mondino FoundationPaviaItaly
- Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific InstituteMilanItaly
| | - Yuri Matteo Falzone
- Neuroimmunology Research UnitIRCCS Mondino FoundationPaviaItaly
- Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific InstituteMilanItaly
| |
Collapse
|
2
|
Oeztuerk M, Henes A, Schroeter CB, Nelke C, Quint P, Theissen L, Meuth SG, Ruck T. Current Biomarker Strategies in Autoimmune Neuromuscular Diseases. Cells 2023; 12:2456. [PMID: 37887300 PMCID: PMC10605022 DOI: 10.3390/cells12202456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/09/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Inflammatory neuromuscular disorders encompass a diverse group of immune-mediated diseases with varying clinical manifestations and treatment responses. The identification of specific biomarkers has the potential to provide valuable insights into disease pathogenesis, aid in accurate diagnosis, predict disease course, and monitor treatment efficacy. However, the rarity and heterogeneity of these disorders pose significant challenges in the identification and implementation of reliable biomarkers. Here, we aim to provide a comprehensive review of biomarkers currently established in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), and idiopathic inflammatory myopathy (IIM). It highlights the existing biomarkers in these disorders, including diagnostic, prognostic, predictive and monitoring biomarkers, while emphasizing the unmet need for additional specific biomarkers. The limitations and challenges associated with the current biomarkers are discussed, and the potential implications for disease management and personalized treatment strategies are explored. Collectively, biomarkers have the potential to improve the management of inflammatory neuromuscular disorders. However, novel strategies and further research are needed to establish clinically meaningful biomarkers.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.O.); (A.H.); (P.Q.)
| |
Collapse
|
3
|
Villalta D, Fabris M, Verriello L, Grizzo F, Mobilia EM, Lechiara A, Pesce G. Acetylcholine receptor and muscle-specific tyrosine kinase antibodies detection: is it time for a change? Clin Chem Lab Med 2023; 61:e189-e191. [PMID: 37013597 DOI: 10.1515/cclm-2023-0205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023]
Affiliation(s)
- Danilo Villalta
- Immunology and Allergy Unit, S. Maria degli Angeli Hospital, Pordenone, Italy
| | - Martina Fabris
- Institute of Clinical Pathology, Santa Maria della Misericordia University Hospital, Udine, Italy
| | - Lorenzo Verriello
- Neurology Unit, Santa Maria della Misericordia University Hospital, Udine, Italy
| | - Francesca Grizzo
- Immunology and Allergy Unit, S. Maria degli Angeli Hospital, Pordenone, Italy
| | | | - Anastasia Lechiara
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Giampaola Pesce
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
- Autoimmunity Laboratory, Department of internal Medicine and Specialties (DiMI), University of Genova, Genova, Italy
| |
Collapse
|
4
|
Vinciguerra C, Bevilacqua L, Lupica A, Ginanneschi F, Piscosquito G, Rini N, Rossi A, Barone P, Brighina F, Di Stefano V. Diagnosis and Management of Seronegative Myasthenia Gravis: Lights and Shadows. Brain Sci 2023; 13:1286. [PMID: 37759888 PMCID: PMC10526522 DOI: 10.3390/brainsci13091286] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Myasthenia gravis (MG) is an antibody-mediated neuromuscular disease affecting the neuromuscular junction. In most cases, autoantibodies can be detected in the sera of MG patients, thus aiding in diagnosis and allowing for early screening. However, there is a small proportion of patients who have no detectable auto-antibodies, a condition termed "seronegative MG" (SnMG). Several factors contribute to this, including laboratory test inaccuracies, decreased antibody production, immunosuppressive therapy, immunodeficiencies, antigen depletion, and immune-senescence. The diagnosis of SnMG is more challenging and is based on clinical features and neurophysiological tests. The early identification of these patients is needed in order to ensure early treatment and prevent complications. This narrative review aims to examine the latest updates on SnMG, defining the clinical characteristics of affected patients, diagnostic methods, management, and therapeutic scenarios.
Collapse
Affiliation(s)
- Claudia Vinciguerra
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Liliana Bevilacqua
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Antonino Lupica
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Federica Ginanneschi
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (F.G.)
| | - Giuseppe Piscosquito
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Nicasio Rini
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Alessandro Rossi
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (F.G.)
| | - Paolo Barone
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Filippo Brighina
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Vincenzo Di Stefano
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| |
Collapse
|
5
|
Li Z, Zhang C, Chang T, Zhang X, Yang H, Gao F, Feng J, Liu H, Chen S, Wang L, Yang C, Li H, Pan Y, Palace J, Shi FD. A multicentre, prospective, double-blind study comparing the accuracy of autoantibody diagnostic assays in myasthenia gravis: the SCREAM study. THE LANCET REGIONAL HEALTH. WESTERN PACIFIC 2023; 38:100846. [PMID: 37554174 PMCID: PMC10404541 DOI: 10.1016/j.lanwpc.2023.100846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 08/10/2023]
Abstract
BACKGROUND Laboratory determination of autoantibodies against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) and other autoantigens have been integrated into the diagnosis of myasthenia gravis (MG). However, evidence supporting the selection of methodologies is lacking. METHODS In this prospective, multicentre cohort study, we recruited patients with suspected MG to evaluate the diagnostic accuracy of cell-based assay (CBA), radioimmunoprecipitation assay (RIPA) and enzyme-linked immunosorbent assay (ELISA) in detecting AChR and MuSK autoantibodies. This study is registered with www.clinicaltrials.gov, number NCT05219097. FINDINGS 2272 eligible participants were recruited, including 2043 MG, 229 non-MG subjects. AChR antibodies were detected in 1478, 1310, and 1280 out of a total of 2043 MG patients by CBA, RIPA, and ELISA, respectively; sensitivity, 72.3% (95% CI, 70.3-74.3), 64.1% (95% CI, 62.0-66.2), 62.7% (95% CI, 60.5-64.8); specificity, 97.8% (95% CI, 95.0-99.3), 97.8% (95% CI, 95.0-99.3), 94.8% (95% CI, 91.9-97.7). MuSK antibodies were found in 59, 50, and 54 from 2043 MG patients by CBA, RIPA and ELISA, respectively; sensitivity, 2.9% (95% CI, 2.2-3.7), 2.4% (95% CI, 1.8-3.2), 2.6% (95% CI, 2.0-3.4); specificity, 100% (95% CI, 98.4-100), 100% (95% CI, 98.4-100), and 99.1% (95% CI, 96.9-99.9). The area under the curve of AChR antibodies tested by CBA was 0.858, and there were statistical differences with RIPA (0.843; p = 0.03) and ELISA (0.809; p < 0.0001). INTERPRETATION CBA has a higher diagnostic accuracy compared to RIPA or ELISA in detecting AChR and MuSK autoantibodies for MG diagnosis. FUNDING New Terrain Biotechnology, Inc., Tianjin, China.
Collapse
Affiliation(s)
- Zhiguo Li
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Chao Zhang
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Ting Chang
- Department of Neurology, Tangdu Hospital, Air Force Medical University, Xi'an, Shanxi, China
| | - Xinghu Zhang
- Centre for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Feng Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jinzhou Feng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hongbo Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Sheng Chen
- Department of Neurology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lihua Wang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Chunsheng Yang
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Huining Li
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuesong Pan
- Centre for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jacqueline Palace
- Department of Neurology, John Radcliffe Hospital Oxford, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
| | - Fu-Dong Shi
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
- Centre for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
6
|
Hajdukovic L, Palibrk A, Peric S, Basta I, Minic R, Jankovic M, Lavrnic D. Galactosylation of serum immunoglobulin G in myasthenia gravis with different autoantibodies. Scand J Clin Lab Invest 2023; 83:348-355. [PMID: 37428449 DOI: 10.1080/00365513.2023.2230550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/11/2023]
Abstract
Myasthenia gravis (MG) is a disease with impaired transmission at the neuromuscular junction, characterised by weakness and fatigability of skeletal muscles. In acquired autoimmune MG, antibodies against acetylcholine receptor (AChRAb) or muscle-specific tyrosine kinase (MuSKAb) are present. There is not much data about immunoglobulin G (IgG) galactosylation in MG, and none based on interactions with lectins. This study aims to examine IgG galactosylation in two types of myasthenia, using affinity immunoelectrophoresis with lectin concanavalin A (Con A). Affinity of Con A-IgG interaction, expressed as retardation coefficient (R), indicated the presence of degalactosylated IgG. The average R values were significantly different between three examined groups, being the lowest in controls (healthy subjects), higher in acetylcholine receptor (AChR) MG, and the highest in muscle-specific tyrosine kinase (MuSK) MG (ANOVA, p < .05). This indicated decreased galactosylation of IgG in both types of MG compared to controls, more pronounced in MuSK MG. IgG galactosylation was also investigated in relation to the disease severity score, determined according to the Myasthenia Gravis Foundation of America (MGFA) criteria, at the time of diagnosis, nadir of the disease and last check-out visit. The average R values for mild disease (stages I-IIIa) were significantly lower than for severe disease (stages IIIb-V), both at the time of diagnosis (p < .05), and at the nadir of the disease (p < .05). Thus, IgG galactosylation was associated with the presence of specific autoantibodies in MG, as well as with disease severity for both types of MG, and may be a predictive marker of MG outcome.
Collapse
Affiliation(s)
- Ljiljana Hajdukovic
- Institute for the Application of Nuclear Energy, INEP, University of Belgrade, Belgrade, Serbia
| | - Aleksa Palibrk
- Faculty of Medicine, Neurology Clinic, University of Belgrade, University Clinical Center of Serbia, Belgrade, Serbia
| | - Stojan Peric
- Faculty of Medicine, Neurology Clinic, University of Belgrade, University Clinical Center of Serbia, Belgrade, Serbia
| | - Ivana Basta
- Faculty of Medicine, Neurology Clinic, University of Belgrade, University Clinical Center of Serbia, Belgrade, Serbia
| | - Rajna Minic
- Institute for Medical Research, Group for Immunology, University of Belgrade, National Institute of Republic of Serbia, Belgrade, Serbia
| | - Miroslava Jankovic
- Institute for the Application of Nuclear Energy, INEP, University of Belgrade, Belgrade, Serbia
| | - Dragana Lavrnic
- Faculty of Medicine, Neurology Clinic, University of Belgrade, University Clinical Center of Serbia, Belgrade, Serbia
| |
Collapse
|
7
|
Yaman A, Kurtuluş Aydın F. Therapeutic and prognostic features in myasthenia gravis patients followed in a tertiary neuromuscular diseases center in Turkey. Front Neurol 2023; 14:1176636. [PMID: 37602241 PMCID: PMC10436092 DOI: 10.3389/fneur.2023.1176636] [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: 02/28/2023] [Accepted: 07/23/2023] [Indexed: 08/22/2023] Open
Abstract
Introduction In this study, we aim to evaluate the treatment responses and prognostic characteristics of Myasthenia Gravis (MG) patients followed in a tertiary neuromuscular diseases center in Turkey. Methods One hundred seventy four MG patients (between years 2011 and 2022) in Antalya, Turkey were diagnosed, and evaluated on a classification of MG was based on Myasthenia. Gravis Foundation of America (MGFA) clinical classification. Exclusion of other possible diseases in the differential diagnosis and support by beneficial response to treatment with acetylcholinesterase inhibitors were also taken into consideration. Results Mean age of participants was 54.86 (SD = 14.856; min-max = 22-84). Ninety (51.7%) were female. MG was more common in women under the age of 65 (58%) and in men over the age of 65 (64%). Generalized MG was seen in 75.3% of the patients. Anti-AChR positivities were detected in 52.3%, Anti-MuSK positivity in 4.6%, and seronegativity in 22.4%. Thymoma was detected in nearly 9.8% and thymectomy was performed in 28.7 percent. Most of the patients (57.5%) were using corticosteroids. Azathioprine was used by 39% and mycophenolate mofetil by 10.3% of patients. Mortality was higher and disease was more severe in late-onset (>50 years) MG patients (especially in the COVID-19 pandemic). Eight patients (four women, four men, mean age 75.5 years) died during follow-up. None of them died due to myasthenic worsening, two died due to malignancy and two due to infection. During the COVID pandemic, 16 patients (9.2%) had COVID infection. Four patients died due to COVID-19 infection, these four patients had serious comorbidities, and three of them were elderly (>75 years). Conclusion In conclusion, MG is more common in women between the ages of 20-40 and in men over the age of 65. The use of corticosteroids was more common under the age of 50, and the use of non-steroidal immunosuppressant agents was more common over the age of 50. Thymectomy is still an important supportive treatment approach in anti-AChR positive and seronegative generalized patients under 50 years of age. IVIG and plasmapheresis are effective treatments during acute exacerbations and bridging periods of treatments. Specific treatments are needed especially for resistant group of patients.
Collapse
Affiliation(s)
- Aylin Yaman
- Neurology Department, Antalya Training and Research Hospital, Antalya, Türkiye
| | - Fatma Kurtuluş Aydın
- Neurology Department, Antalya Training and Research Hospital, Antalya, Türkiye
- Ankara Etlik City Hospital, Ankara, Türkiye
| |
Collapse
|
8
|
Vakrakou AG, Karachaliou E, Chroni E, Zouvelou V, Tzanetakos D, Salakou S, Papadopoulou M, Tzartos S, Voumvourakis K, Kilidireas C, Giannopoulos S, Tsivgoulis G, Tzartos J. Immunotherapies in MuSK-positive Myasthenia Gravis; an IgG4 antibody-mediated disease. Front Immunol 2023; 14:1212757. [PMID: 37564637 PMCID: PMC10410455 DOI: 10.3389/fimmu.2023.1212757] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/05/2023] [Indexed: 08/12/2023] Open
Abstract
Muscle-specific kinase (MuSK) Myasthenia Gravis (MG) represents a prototypical antibody-mediated disease characterized by predominantly focal muscle weakness (neck, facial, and bulbar muscles) and fatigability. The pathogenic antibodies mostly belong to the immunoglobulin subclass (Ig)G4, a feature which attributes them their specific properties and pathogenic profile. On the other hand, acetylcholine receptor (AChR) MG, the most prevalent form of MG, is characterized by immunoglobulin (Ig)G1 and IgG3 antibodies to the AChR. IgG4 class autoantibodies are impotent to fix complement and only weakly bind Fc-receptors expressed on immune cells and exert their pathogenicity via interfering with the interaction between their targets and binding partners (e.g. between MuSK and LRP4). Cardinal differences between AChR and MuSK-MG are the thymus involvement (not prominent in MuSK-MG), the distinct HLA alleles, and core immunopathological patterns of pathology in neuromuscular junction, structure, and function. In MuSK-MG, classical treatment options are usually less effective (e.g. IVIG) with the need for prolonged and high doses of steroids difficult to be tapered to control symptoms. Exceptional clinical response to plasmapheresis and rituximab has been particularly observed in these patients. Reduction of antibody titers follows the clinical efficacy of anti-CD20 therapies, a feature implying the role of short-lived plasma cells (SLPB) in autoantibody production. Novel therapeutic monoclonal against B cells at different stages of their maturation (like plasmablasts), or against molecules involved in B cell activation, represent promising therapeutic targets. A revolution in autoantibody-mediated diseases is pharmacological interference with the neonatal Fc receptor, leading to a rapid reduction of circulating IgGs (including autoantibodies), an approach already suitable for AChR-MG and promising for MuSK-MG. New precision medicine approaches involve Chimeric autoantibody receptor T (CAAR-T) cells that are engineered to target antigen-specific B cells in MuSK-MG and represent a milestone in the development of targeted immunotherapies. This review aims to provide a detailed update on the pathomechanisms involved in MuSK-MG (cellular and humoral aberrations), fostering the understanding of the latest indications regarding the efficacy of different treatment strategies.
Collapse
Affiliation(s)
- Aigli G. Vakrakou
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleni Karachaliou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Patras, Greece
| | - Vasiliki Zouvelou
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Tzanetakos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Stavroula Salakou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marianna Papadopoulou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Department of Physiotherapy, University of West Attica, Athens, Greece
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Department of Pharmacy, University of Patras, Patras, Greece
| | - Konstantinos Voumvourakis
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Kilidireas
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Department of Neurology, Henry Dunant Hospital Center, Athens, Greece
| | - Sotirios Giannopoulos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Tsivgoulis
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Department of Neurology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - John Tzartos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|
9
|
Abstract
Myasthenia gravis is an autoimmune disorder caused by antibodies against elements in the postsynaptic membrane at the neuromuscular junction, which leads to muscle weakness. Congenital myasthenic syndromes are rare and caused by mutations affecting pre- or postsynaptic function at the neuromuscular synapse and resulting in muscle weakness. MG has a prevalence of 150-250 and an annual incidence of 8-10 individuals per million. The majority has disease onset after age 50 years. Juvenile MG with onset in early childhood is more common in East Asia. MG is subgrouped according to type of pathogenic autoantibodies, age of onset, thymus pathology, and generalization of muscle weakness. More than 80% have antibodies against the acetylcholine receptor. The remaining have antibodies against MuSK, LRP4, or postsynaptic membrane antigens not yet identified. A thymoma is present in 10% of MG patients, and more than one-third of thymoma patients develop MG as a paraneoplastic condition. Immunosuppressive drug therapy, thymectomy, and symptomatic drug therapy with acetylcholine esterase inhibitors represent cornerstones in the treatment. The prognosis is good, with the majority of patients having mild or moderate symptoms only. Most congenital myasthenic syndromes are due to dysfunction in the postsynaptic membrane. Symptom debut is in early life. Symptomatic drug treatment has sometimes a positive effect.
Collapse
Affiliation(s)
- Nils Erik Gilhus
- Department of Neurology, Haukeland University Hospital and Department of Clinical Medicine, University of Bergen, Bergen, Norway.
| |
Collapse
|
10
|
Bedside and laboratory diagnostic testing in myasthenia. J Neurol 2022; 269:3372-3384. [PMID: 35142871 PMCID: PMC9119875 DOI: 10.1007/s00415-022-10986-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/02/2022]
Abstract
Myasthenia gravis (MG) and congenital myasthenic syndromes (CMS) are a group of disorders with a well characterised autoimmune or genetic and neurophysiological basis. We reviewed the literature from the last 20 years assessing the utility of various neurophysiological, immunological, provocative and genetic tests in MG and CMS. Diagnostic sensitivity of repetitive nerve stimulation test ranges between 14 and 94% and specificity between 73 and 100%; sensitivity of single-fibre EMG (SFEMG) test ranges between 64 and 100% and specificity between 22 and 100%; anti-acetylcholine receptor (AChR) antibody sensitivity ranges from 13 to 97% and specificity ranges from 95 to 100%. Overall, SFEMG has the highest sensitivity while positive anti-AChR antibodies have the highest specificity. Newer testing strategies that have been investigated over the last couple of decades include ocular vestibular-evoked myogenic potentials, otoacoustic emissions and disease-specific circulating miRNAs in serum for autoimmune myasthenia, as well as next-generation sequencing for genetic testing of CMS. While there has been significant progress in developing newer testing strategies for diagnosing MG and CMS over the last couple of decades, more research is needed to assess the utility of these newer tools regarding their sensitivity and specificity.
Collapse
|
11
|
Ge X, Wei C, Dong H, Zhang Y, Bao X, Wu Y, Song D, Hao H, Xiong H. Juvenile Generalized Myasthenia Gravis With AChR and MuSK Antibody Double Positivity: A Case Report With a Review of the Literature. Front Pediatr 2022; 10:788353. [PMID: 35633954 PMCID: PMC9131937 DOI: 10.3389/fped.2022.788353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 04/04/2022] [Indexed: 11/24/2022] Open
Abstract
Myasthenia gravis is an autoimmune disease mediated by B cells and is associated with acetylcholine receptor (AChR) and muscle-specific receptor tyrosine kinase (MuSK) antibodies in the postsynaptic membrane at the neuromuscular junction. The presence of both antibodies in the serum of patients with myasthenia gravis has been rarely reported. Case description: A 9-year-old girl was admitted to our hospital with the chief complaints of reduced facial expression for 3 months and unclear speech and choking from drinking water for 2 months. The diagnosis of generalized myasthenia gravis was made based on clinical manifestations, repetitive electrical nerve stimulation, neostigmine tests, specific antibody tests and other auxiliary examinations. We found the rare coexistence of two key antibodies (anti-AChR and anti-MuSK antibodies) in the patient's serum. The patient experienced myasthenic crisis and received respiratory support even though she was taking prednisone therapy. Due to the poor response to treatment with pyridostigmine bromide, glucocorticoids and IVIG, we administered rituximab therapy, and she responded well and achieved clinical remission. This suggests that clinicians should pay more attention to atypical cases and antibody detection. Rituximab should be considered when conventional treatment fails.
Collapse
Affiliation(s)
- XiuShan Ge
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - CuiJie Wei
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Dong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - YueHua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - XinHua Bao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - DanYu Song
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - HongJun Hao
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| |
Collapse
|
12
|
Bortone F, Scandiffio L, Cavalcante P, Mantegazza R, Bernasconi P. Epstein-Barr Virus in Myasthenia Gravis: Key Contributing Factor Linking Innate Immunity with B-Cell-Mediated Autoimmunity. Infect Dis (Lond) 2021. [DOI: 10.5772/intechopen.93777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Epstein-Barr virus (EBV), a common human herpes virus latently infecting most of the world’s population with periodic reactivations, is the main environmental factor suspected to trigger and/or sustain autoimmunity by its ability to disrupt B-cell tolerance checkpoints. Myasthenia gravis (MG) is a prototypic autoimmune disorder, mostly caused by autoantibodies to acetylcholine receptor (AChR) of the neuromuscular junction, which cause muscle weakness and fatigability. Most patients display hyperplastic thymus, characterized by ectopic germinal center formation, chronic inflammation, exacerbated Toll-like receptor activation, and abnormal B-cell activation. After an overview on MG clinical features and intra-thymic pathogenesis, in the present chapter, we describe our main findings on EBV presence in MG thymuses, including hyperplastic and thymoma thymuses, in relationship with innate immunity activation and data from other autoimmune conditions. Our overall data strongly indicate a critical contribution of EBV to innate immune dysregulation and sustained B-cell-mediated autoimmune response in the pathological thymus of MG patients.
Collapse
|
13
|
Evoli A, Spagni G, Monte G, Damato V. Heterogeneity in myasthenia gravis: considerations for disease management. Expert Rev Clin Immunol 2021; 17:761-771. [PMID: 34043932 DOI: 10.1080/1744666x.2021.1936500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Myasthenia gravis is a rare disease of the neuromuscular junction and a prototype of B cell-driven immunopathology. Pathogenic antibodies target post-synaptic transmembrane proteins, most commonly the nicotinic acetylcholine receptor and the muscle-specific tyrosine kinase, inducing end-plate alterations and neuromuscular transmission impairment. Several clinical subtypes are distinct on the basis of associated antibodies, age at symptom onset, thymus pathology, genetic factors, and weakness distribution. These subtypes have distinct pathogenesis that can account for different responses to treatment. Conventional therapy is based on the use of symptomatic agents, steroids, immunosuppressants and thymectomy. Of late, biologics have emerged as effective therapeutic options.Areas covered: In this review, we will discuss the management of myasthenia gravis in relation to its phenotypic and biological heterogeneity, in the light of recent advances in the disease immunopathology, new diagnostic tools, and results of clinical trialsExpert opinion: Clinical management is shaped on serological subtype, and patient age at onset, lifestyle and comorbidities, balancing therapeutic needs and safety. Although reliable biomarkers predictive of clinical and biologic outcome are still lacking, recent developments promise a more effective and safe treatment. Disease subtyping according to serological testing and immunopathology is crucial to the appropriateness of clinical management.
Collapse
Affiliation(s)
- Amelia Evoli
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy.,Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Gregorio Spagni
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Gabriele Monte
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Valentina Damato
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| |
Collapse
|
14
|
Gastaldi M, Scaranzin S, Businaro P, Mobilia E, Benedetti L, Pesce G, Franciotta D. Improving laboratory diagnostics in myasthenia gravis. Expert Rev Mol Diagn 2021; 21:579-590. [PMID: 33970749 DOI: 10.1080/14737159.2021.1927715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Myasthenia gravis (MG) is a prototypical autoimmune disease, characterized by pathogenic autoantibodies targeting structures of the neuromuscular junction. Radioimmunoprecipitation assays (RIPAs) represent the gold standard for their detection. However, new methods are emerging to complement, or overcome RIPAs, also with the perspective of eliminating the use of radioactive reagents.Areas covered: We discuss advances in laboratory methods, prompted especially by cell-based assays (CBAs), for the detection of the autoantibodies of MG diagnostics, above all those to the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low molecular-weight receptor-related low-density lipoprotein-4 (LRP4).Expert opinion: CBA technology makes AChRs aggregate on cell membranes, thus allowing to detect autoantibodies to clustered AChRs, with reduction of seronegative MG cases. The diagnostic relevance of RIPA/CBA-measurable LRP4 antibodies is still unclear, in Caucasian patients at least. Live CBAs for the detection of AChR, MuSK, and LRP4 antibodies might represent an alternative to RIPAs, but first require full validation. CBAs could be used as screening tests, limiting RIPAs for antibody quantification. To this end, ELISAs might be an alternative.Fixation procedures preserving enough degree of antigen conformationality could yield AChR and MuSK CBAs suitable for a wide use in clinical-chemistry laboratories.
Collapse
Affiliation(s)
- Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Silvia Scaranzin
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Pietro Businaro
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Emanuela Mobilia
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Luana Benedetti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Giampaola Pesce
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine (Dimi), University of Genova, Genova, Italy
| | - Diego Franciotta
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| |
Collapse
|
15
|
AChRAb and MuSKAb double-seropositive myasthenia gravis: a distinct subtype? Neurol Sci 2021; 42:863-869. [PMID: 33438140 PMCID: PMC7870615 DOI: 10.1007/s10072-021-05042-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/04/2021] [Indexed: 11/07/2022]
Abstract
Introduction This study investigated the characteristics of double-seropositive myasthenia gravis (DSP-MG) in southern China for disease subtype classification. Methods A case-control study was carried out in which the characteristics of DSP-MG patients (n = 17) were compared to those of muscle-specific tyrosine kinase antibody-positive (MuSK)-MG and acetylcholine receptor antibody-positive (AChR)-MG patients (n = 8 and 27, respectively). We also performed a literature review of DSP-MG patients. Results Compared to AChR-MG, DSP-MG had greater bulbar dysfunction (47.1% vs 18.6%, P = 0.04), higher incidence of myasthenia crisis (41.2% vs 14.8%, P = 0.04), more severe Myasthenia Gravis Foundation of America classification at maximum worsening, greater autoantibody abnormalities (70.6% vs 33.3%, P = 0.015), greater need for immunosuppressant treatment (58.8% vs 3.7%, P < 0.001), and worse prognosis with less remission (11.8% vs 55.6%, P = 0.001). There were no differences between DSP-MG and MuSK-MG patients. DSP-MG described in published reports was comparable to MuSK-MG. Discussion DSP-MG in southern China may be a subtype of MuSK-MG.
Collapse
|
16
|
Kim MJ, Kim SW, Kim M, Choi YC, Kim SM, Shin HY. Evaluating an In-House Cell-Based Assay for Detecting Antibodies Against Muscle-Specific Tyrosine Kinase in Myasthenia Gravis. J Clin Neurol 2021; 17:400-408. [PMID: 34184448 PMCID: PMC8242307 DOI: 10.3988/jcn.2021.17.3.400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/11/2023] Open
Abstract
Background and Purpose Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cell-based assay (CBA) to detect MuSK Abs. Methods A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). Results The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen's kappa=0.880, p<0.001) and ELISA (Cohen's kappa=0.982, p<0.001). Conclusions The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.
Collapse
Affiliation(s)
- Min Ju Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.,Graduate Program of Nanoscience and Technology, Yonsei University, Seoul, Korea
| | - Seung Woo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - MinGi Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Young Chul Choi
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Min Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Ha Young Shin
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
| |
Collapse
|
17
|
Frykman H, Kumar P, Oger J. Immunopathology of Autoimmune Myasthenia Gravis: Implications for Improved Testing Algorithms and Treatment Strategies. Front Neurol 2020; 11:596621. [PMID: 33362698 PMCID: PMC7755715 DOI: 10.3389/fneur.2020.596621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is a heterogeneous condition, characterized by autoantibodies (Abs) that target functionally important structures within neuromuscular junctions (NMJ), thus affecting nerve-to-muscle transmission. MG patients are more often now subgrouped based on the profile of serum autoantibodies, which segregate with clinical presentation, immunopathology, and their response to therapies. The serological testing plays an essential role in confirming MG diagnosis and guiding disease management, although a small percentage of MG patients remain negative for antibodies. With the advancements in new highly effective pathophysiologically-specific immunotherapeutic options, it has become increasingly important to identify the specific Abs responsible for the pathogenicity in individual MG patients. There are several new assays and protocols being developed for the improved detection of Abs in MG patients. This review focuses on the divergent immunopathological mechanisms in MG, and discusses their relevance to improved diagnostic and treatment. We propose a comprehensive "reflex testing," algorithm for the presence of MG autoantibodies, and foresee that in the near future, the convenience and specificity of novel assays will permit the clinicians to consider them into routine systematic testing, thus stimulating laboratories to make these tests available. Moreover, adopting treatment driven testing algorithms will be crucial to identify subgroups of patients potentially benefiting from novel immunotherapies for MG.
Collapse
Affiliation(s)
- Hans Frykman
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
| | - Pankaj Kumar
- BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
| | - Joel Oger
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
18
|
Lazaridis K, Tzartos SJ. Myasthenia Gravis: Autoantibody Specificities and Their Role in MG Management. Front Neurol 2020; 11:596981. [PMID: 33329350 PMCID: PMC7734299 DOI: 10.3389/fneur.2020.596981] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/30/2020] [Indexed: 12/11/2022] Open
Abstract
Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction, characterized by skeletal muscle weakness and fatigability. It is caused by autoantibodies targeting proteins of the neuromuscular junction; ~85% of MG patients have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 5% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). In the remaining about 10% of patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG). Since serological tests are relatively easy and non-invasive for disease diagnosis, the improvement of methods for the detection of known autoantibodies or the discovery of novel autoantibody specificities to diminish SN-MG and to facilitate differential diagnosis of similar diseases, is crucial. Radioimmunoprecipitation assays (RIPA) are the staple for MG antibody detection, but over the past years, using cell-based assays (CBAs) or improved highly sensitive RIPAs, it has been possible to detect autoantibodies in previously SN-MG patients. This led to the identification of more patients with antibodies to the classical antigens AChR and MuSK and to the third MG autoantigen, the low-density lipoprotein receptor-related protein 4 (LRP4), while antibodies against other extracellular or intracellular targets, such as agrin, Kv1.4 potassium channels, collagen Q, titin, the ryanodine receptor and cortactin have been found in some MG patients. Since the autoantigen targeted determines in part the clinical manifestations, prognosis and response to treatment, serological tests are not only indispensable for initial diagnosis, but also for monitoring treatment efficacy. Importantly, knowing the autoantibody profile of MG patients could allow for more efficient personalized therapeutic approaches. Significant progress has been made over the past years toward the development of antigen-specific therapies, targeting only the specific immune cells or autoantibodies involved in the autoimmune response. In this review, we will present the progress made toward the development of novel sensitive autoantibody detection assays, the identification of new MG autoantigens, and the implications for improved antigen-specific therapeutics. These advancements increase our understanding of MG pathology and improve patient quality of life by providing faster, more accurate diagnosis and better disease management.
Collapse
Affiliation(s)
| | - Socrates J Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece.,Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| |
Collapse
|
19
|
Abstract
PURPOSE OF REVIEW This article provides an update on the most recent advances in diagnostic procedures and therapeutic approaches for myasthenia gravis, spanning from autoantibody and neuroelectrophysiological tests as diagnostic tools, to innovative and promising treatments based on biological drugs. RECENT FINDINGS Novel studies performed by cell-based assays (CBAs) indicate an improvement in the chance of identifying serum autoantibodies in myasthenic patients. Clinical trials on the use of biological drugs were recently concluded, providing important data on safety and efficacy of eculizumab, efgartigimod and amifampridine phosphate: the first, a complement blocker, showed long-term safety and efficacy in acetylcholine receptor (AChR)-positive myasthenic patients with refractory generalized disease; the second, the neonatal Fc receptor blocker, was well tolerated and clinically effective in both AChR-specific and muscle-specific kinase receptor (MuSK)-positive patients; the third, a blocker of presynaptic potassium channels, was found to be well tolerated and effective in MuSK-positive patients. SUMMARY CBAs can lead to a significant reduction of seronegative patients, improving myasthenia gravis diagnostic process. New biological drugs offer innovative approaches to treat myasthenic patients with generalized disease, promising to change the paradigm of treatment and to significantly enhance therapeutic success within a precision medicine framework.
Collapse
|
20
|
Gilhus NE. Myasthenia Gravis Can Have Consequences for Pregnancy and the Developing Child. Front Neurol 2020; 11:554. [PMID: 32595594 PMCID: PMC7304249 DOI: 10.3389/fneur.2020.00554] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/15/2020] [Indexed: 12/24/2022] Open
Abstract
Myasthenia gravis (MG) with onset below 50 years, thymic hyperplasia and acetylcholine receptor (AChR) antibodies is more common in females than in males. For a relatively large group of MG patients, pregnancy represents therefore an important question. The muscle weakness, the circulating autoantibodies, the hyperplastic thymus, the MG drug treatment, and any autoimmune comorbidity may all influence both mother and child health during pregnancy and also during breastfeeding in the postpartum period. Mother's MG remains stable in most patients during pregnancy. Pyridostigmine, prednisolone, and azathioprine are regarded as safe during pregnancy. Mycophenolate, methotrexate and cyclophosphamide are teratogenic and should not be used by women with the potential to become pregnant. Rituximab should not be given during the last few months before conception and not during pregnancy. Intravenous immunoglobulin and plasma exchange can be used for exacerbations or when need for intensified therapy. Pregnancies in MG women are usually without complications. Their fertility is near normal. Vaginal delivery is recommended. MG patients have an increased rate of Cesarean section, partly due to their muscle weakness and to avoid exhaustion, partly as a precaution that is often unnecessary. Around 10% of the newborn develop neonatal myasthenia during the first few days after birth. This is transient and usually mild with some sucking and swallowing difficulties. In rare cases, transplacental transfer of AChR antibodies leads to permanent muscle weakness in the child, and arthrogryposis with joint contractures. Repeated spontaneous abortions have been described due to AChR antibodies. MG women should always give birth at hospitals with experience in newborn intensive care. MG does not represent a reason for not having children, and the patients should be supported in their wish of becoming pregnant.
Collapse
Affiliation(s)
- Nils Erik Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Neurology, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
21
|
Muscle involvement in myasthenia gravis: Expanding the clinical spectrum of Myasthenia-Myositis association from a large cohort of patients. Autoimmun Rev 2020; 19:102498. [PMID: 32062029 DOI: 10.1016/j.autrev.2020.102498] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/16/2022]
Abstract
Myastenia-Inflammatory Myopathy (MG-IM) association has been described in less than 50 cases, as isolated reports or in few case series. In most cases, MG and IM onset occur simultaneously even if the overlapping clinical manifestations could lead to delay the diagnosis in the early stage of disease. In these cases, thymic pathology is present in more than 50% of cases. Pathological findings can be consistent of polymyositis (63%), dermatomyositis (25%) or granulomatosis (12%). Accurate clinical manifestations and severity of IM in MG, including muscle specific antibodies (MSA) and muscle MRI, have not been systematically investigated and focal or mild subclinical myositis have not been reported. We observed that focal myositis or asymptomatic CK elevation can also occur in MG. In this review we have also retrospectively re-analyzed the clinical, serological, pathological and muscle imaging data from 13 patients with MG- IM from our cohort of 441 MG patients (2,9%). Clinical onset occurred simultaneously in 10/13 patients, whereas in 2 patients the IM appeared later in MG disease course (range 10-14 years) and conversely in 1 patient MG symptoms occurred later in IM disease course (4 years). Median age at disease onset was 51 year (range 24-73 years) regardless of clinical onset (MG or IM). Median clinical follow-up was 88 months (range 31-237 months). IM was suspected by CK elevation in all patients (ranging 800-3000 UI/L at first detection) and non-fatigable muscle weakness unresponsive to acetylcholinesterase inhibitors. All the patients presented mild to moderate MG symptoms. Three main categories of muscle involvement, sometimes overlapping, were recognizable: distal, proximal and subclinical myositits, leading to three main clinical groups (A,B,C) and two overlapping subgroups (A/B and B/C). Thymus pathology was present in 10/13 patients. Anti-AChR was detected in al all patients associated with anti-Titin and -RyR1 in those patients with thymoma. No MSA, nor MAA antibodies were detected. Muscle biopsy confirmed IM in all patients. In conclusion we redefined the clinical spectrum of muscle involvement in MG-IM association, which represent a continuum among 3 main clinical groups: distal, proximal and subclinical muscle involvement. Minimal muscle involvement and focal myositis could be underestimated among myasthenic patients and early aggressive immunotherapy could be required in focal group.
Collapse
|
22
|
Lazaridis K, Tzartos SJ. Autoantibody Specificities in Myasthenia Gravis; Implications for Improved Diagnostics and Therapeutics. Front Immunol 2020; 11:212. [PMID: 32117321 PMCID: PMC7033452 DOI: 10.3389/fimmu.2020.00212] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and fatiguability of skeletal muscles. It is an antibody-mediated disease, caused by autoantibodies targeting neuromuscular junction proteins. In the majority of patients (~85%) antibodies against the muscle acetylcholine receptor (AChR) are detected, while in 6% antibodies against the muscle-specific kinase (MuSK) are detected. In ~10% of MG patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG), making the improvement of methods for the detection of known autoantibodies or the discovery of novel antigenic targets imperative. Over the past years, using cell-based assays or improved highly sensitive immunoprecipitation assays, it has been possible to detect autoantibodies in previously SN-MG patients, including the identification of the low-density lipoprotein receptor-related protein 4 (LRP4) as a third MG autoantigen, as well as AChR and MuSK antibodies undetectable by conventional methods. Furthermore, antibodies against other extracellular or intracellular targets, such as titin, the ryanodine receptor, agrin, collagen Q, Kv1.4 potassium channels and cortactin have been found in some MG patients, which can be useful biomarkers. In addition to the improvement of diagnosis, the identification of the patients' autoantibody specificity is important for their stratification into respective subgroups, which can differ in terms of clinical manifestations, prognosis and most importantly their response to therapies. The knowledge of the autoantibody profile of MG patients would allow for a therapeutic strategy tailored to their MG subgroup. This is becoming especially relevant as there is increasing progress toward the development of antigen-specific therapies, targeting only the specific autoantibodies or immune cells involved in the autoimmune response, such as antigen-specific immunoadsorption, which have shown promising results. We will herein review the advances made by us and others toward development of more sensitive detection methods and the identification of new antibody targets in MG, and discuss their significance in MG diagnosis and therapy. Overall, the development of novel autoantibody assays is aiding in the more accurate diagnosis and classification of MG patients, supporting the development of advanced therapeutics and ultimately the improvement of disease management and patient quality of life.
Collapse
Affiliation(s)
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.,Tzartos NeuroDiagnostics, Athens, Greece
| |
Collapse
|
23
|
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).
Collapse
|
24
|
Rivner MH, Pasnoor M, Dimachkie MM, Barohn RJ, Mei L. Muscle-Specific Tyrosine Kinase and Myasthenia Gravis Owing to Other Antibodies. Neurol Clin 2019; 36:293-310. [PMID: 29655451 DOI: 10.1016/j.ncl.2018.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Around 20% of patients with myasthenia gravis are acetylcholine receptor antibody negative; muscle-specific tyrosine kinase antibodies (MuSK) were identified as the cause of myasthenia gravis in 30% to 40% of these cases. Anti MuSK myasthenia gravis is associated with specific clinical phenotypes. One is a bulbar form with fewer ocular symptoms. Others show an isolated head drop or symptoms indistinguishable from acetylcholine receptor-positive myasthenia gravis. These patients usually respond well to immunosuppressive therapy, but not as well to cholinesterase inhibitors. Other antibodies associated with myasthenia gravis, including low-density lipoprotein receptor-related protein 4, are discussed.
Collapse
Affiliation(s)
- Michael H Rivner
- EMG Lab, Augusta University, 1120 15th Street, BP-4390, Augusta, GA 30912, USA.
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Mazen M Dimachkie
- Department of Neurology, University of Kansas Medical Center, 3599 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66103, USA
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 4017, Kansas City, KS 66160, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Augusta University, 1120 15th Street, CA-2014, Augusta, GA 30912, USA
| |
Collapse
|
25
|
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies against the acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or other AChR-related proteins in the postsynaptic muscle membrane. Localized or general muscle weakness is the predominant symptom and is induced by the antibodies. Patients are grouped according to the presence of antibodies, symptoms, age at onset and thymus pathology. Diagnosis is straightforward in most patients with typical symptoms and a positive antibody test, although a detailed clinical and neurophysiological examination is important in antibody-negative patients. MG therapy should be ambitious and aim for clinical remission or only mild symptoms with near-normal function and quality of life. Treatment should be based on MG subgroup and includes symptomatic treatment using acetylcholinesterase inhibitors, thymectomy and immunotherapy. Intravenous immunoglobulin and plasma exchange are fast-acting treatments used for disease exacerbations, and intensive care is necessary during exacerbations with respiratory failure. Comorbidity is frequent, particularly in elderly patients. Active physical training should be encouraged.
Collapse
|
26
|
Nagappa M, Mahadevan A, Gangadhar Y, Patil SA, Bokolia S, Bindu PS, Sinha S, Taly AB. Autoantibodies in acquired myasthenia gravis: Clinical phenotype and immunological correlation. Acta Neurol Scand 2019; 139:428-437. [PMID: 30693486 DOI: 10.1111/ane.13071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/25/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Data on antibody profile in myasthenia gravis (MG) from India are limited. OBJECTIVES To investigate antibody profile in patients with MG and their clinical correlates. PATIENTS AND METHODS Patients of MG (n = 85, M:F::1.1:1, mean age: 39.29 ± 17.3 years, mean symptom duration: 72.94 ± 91.8 months) were evaluated for clinical features, MG foundation of America (MGFA) score, response to treatment, and outcome at last follow-up. Antibodies to acetylcholine receptor (AChR), muscle-specific kinase (MUSK), titin and ryanodine receptor (RYR) were analysed using ELISA. RESULTS Based on the regional distribution of weakness, the cohort could be categorized as: generalized: 60, ocular: 16 and oculo-bulbar: 9. Sixty patients were followed up for a mean duration of 26.74 ± 13.8 months. Outcome at last follow-up was as follows: remission-22, no remission-33 and dead-5. AChR and MUSK antibodies were detected in 58 and 8 patients, respectively. Frequency of generalized MG, worse MGFA score during the disease course and thymomatous histology significantly correlated with presence of AChR-antibodies, though outcome at last follow-up was comparable between AChR-antibody positive and negative groups. Patients with MUSK antibodies had oculo-bulbar or generalized MG and frequent respiratory crisis, but majority improved or remitted with treatment. Titin antibodies were detected in 31.8% and RYR antibodies in 32.9%. Their presence did not correlate with age at onset of MG, severity or presence of thymoma. CONCLUSION This report highlights the spectrum of antibodies in MG in an Indian cohort. AChR-antibody positivity correlated with clinical severity. Outcome was good in majority of MUSK antibody-positive MG. The role of other antibodies, complementary vs epiphenomenon, remains open.
Collapse
Affiliation(s)
- Madhu Nagappa
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Anita Mahadevan
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Yashwanth Gangadhar
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Shripad A. Patil
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Suresh Bokolia
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Parayil S. Bindu
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Sanjib Sinha
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Arun B. Taly
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| |
Collapse
|
27
|
Abstract
PURPOSE OF REVIEW The current article reviews the recent advances in the field of myasthenia gravis, which span from autoantibody profiling and pathogenic mechanisms to therapy innovation. The overview is highlighting specifically the data and the needs of targeted treatments in the light of precision medicine in myasthenia gravis. RECENT FINDINGS Novel data published recently further increased our knowledge on myasthenia gravis. The use of cell-based assays has greatly improved autoantibody detection in myasthenia gravis patients, and the mechanisms of action of these antibodies have been described. The role of Toll-like receptor activation in the generation of thymic alterations and anti-acetylcholine receptor autosensitization has been further investigated implementing our understanding on the relationships between innate immunity and autoimmunity. Additional studies have been focused on the alterations of T-cell/B-cell regulatory mechanisms in thymus and peripheral blood of myasthenia gravis patients. microRNAs and genetic factors are also emerging as key biomarkers in myasthenia gravis pathogenesis and prediction of drug efficacy in individual patients. SUMMARY The recent immunological and pathological findings in myasthenia gravis promise to improve myasthenia gravis treatment, via the development of more precise and personalized therapies.
Collapse
|
28
|
Prabhakar H, Ali Z. Intensive Care Management of the Neuromuscular Patient. TEXTBOOK OF NEUROANESTHESIA AND NEUROCRITICAL CARE 2019. [PMCID: PMC7120052 DOI: 10.1007/978-981-13-3390-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neuromuscular emergencies are a distinct group of acute neurological diseases with distinct characteristic presentations. Patients who suffer from this group of diseases are at immediate risk of losing protection of their native airway as well as aspirating orogastric contents. This is secondary to weakness of the muscles of the oropharynx and respiratory muscles. Although some neuromuscular emergencies such as myasthenia gravis or Guillain-Barré syndrome are well understood, others such as critical illness myopathy and neuropathy are less well characterized. In this chapter, we have discussed the pathophysiology, diagnostic evaluation, and management options in patients who are admitted to the intensive care unit. We have also emphasized the importance of a thorough understanding of the use of pharmacological anesthetic agents in this patient population.
Collapse
Affiliation(s)
- Hemanshu Prabhakar
- Department of Neuroanaesthesiology and Critical Care, All India Institute of Medical Sciences, New Delhi, India
| | - Zulfiqar Ali
- Division of Neuroanesthesiology, Department of Anesthesiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir India
| |
Collapse
|
29
|
Gilhus NE, Hong Y. Maternal myasthenia gravis represents a risk for the child through autoantibody transfer, immunosuppressive therapy and genetic influence. Eur J Neurol 2018; 25:1402-1409. [PMID: 30133097 DOI: 10.1111/ene.13788] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/17/2018] [Indexed: 12/16/2022]
Abstract
Females with myasthenia gravis (MG) worry about their disease having negative consequences for their children. Autoimmune disease mechanisms, treatment and heredity could all have an impact on the child. This is a subject review where Web of Science was searched for relevant keywords and combinations. Controlled and prospective studies were included, and also results from selected and unselected patient cohorts, guidelines, consensus papers and reviews. Neonatal MG with temporary muscle weakness occurs in 10% of newborn babies where the mother has MG, due to transplacental transfer of antibodies against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or lipoprotein receptor-related protein 4 (LRP4). Arthrogryposis and fetal AChR inactivation syndrome with contractures and permanent myopathy are rare events caused by mother's antibodies against fetal type AChR. The MG drugs pyridostigmine, prednisolone and azathioprine are regarded as safe during pregnancy and breastfeeding. Methotrexate, mycophenolate mofetil and cyclophosphamide are teratogenic. Mother's MG implies at least a 10-fold increased risk for MG and other autoimmune diseases in the child. MG females should receive specific information about pregnancy and giving birth. First-line MG treatments should usually be continued during pregnancy. Intravenous immunoglobulin and plasma exchange represent safe treatments for exacerbations. Neonatal MG risk means that MG women should give birth at hospitals experienced in neonatal intensive care. Neonatal MG needs supportive care, rarely also acetylcholine esterase inhibition or intravenous immunoglobulin. Women with MG should be supported in their wish to have children.
Collapse
Affiliation(s)
- N E Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Y Hong
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| |
Collapse
|
30
|
Quality of life in patients with MuSK positive myasthenia gravis. Acta Neurol Belg 2018; 118:423-427. [PMID: 29594965 DOI: 10.1007/s13760-018-0915-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 03/19/2018] [Indexed: 10/17/2022]
Abstract
It is believed that myasthenia gravis (MG) with antibodies to muscle-specific tyrosine kinase (MuSK) is the most severe form of the disease, especially in the first years of the disease. The aim of our study was to investigate quality of life (QoL) in a population of patients with MuSK MG compared to those with MG who have antibodies to acetylcholine receptor (AChR) in their sera. The study group consisted of 35 MuSK MG patients (28 females and 7 males), while the control group included 38 AChR MG patients matched for gender, age, and duration of the disease. SF-36 questionnaire was used to evaluate the health-related QoL. Following scales were also used: Hamilton's scales for depression and anxiety, the Multidimensional Scale of Perceived Social Support, and the Acceptance of Illness Scale. Physical domain scores of QoL were similarly affected in both MuSK and AChR groups, while mental domain and total SF-36 scores were even better in MuSK MG patients. Social support was better in the MuSK group (77.3 ± 9.3 vs. 70.6 ± 14.1, p < 0.05). SF-36 total score correlated with depression (rho = 0.54, p < 0.01), anxiety (rho = 0.49, p < 0.01), and MSPSS (rho = - 0.35, p < 0.05), and depression was an independent predictor of worse QoL. Besides therapy of weakness, psychiatric treatment and different forms of psychosocial condition should be part of regular therapeutic protocols for MG. Adequate team work of health professionals and family can provide a healthy mental environment in which a MuSK MG patient would feel more comfortable in spite of the disease.
Collapse
|
31
|
Galassi G, Mazzoli M, Ariatti A, Kaleci S, Valzania F, Nichelli PF. Antibody profile may predict outcome in ocular myasthenia gravis. Acta Neurol Belg 2018; 118:435-443. [PMID: 29858757 DOI: 10.1007/s13760-018-0943-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/15/2018] [Indexed: 02/04/2023]
Abstract
An unsolved issue remains whether there are clinical and immunological features to predict in a single patient the risk of conversion from ocular Myasthenia Gravis (OMG) to generalized disease (GMG) as 50-60% of patients may progress within 1-2 years since onset. Anti-acetylcholine receptor antibodies (AChR Abs) are found in up to 50% of OMG patients; muscle-specific tyrosine kinase antibodies (MuSK-Abs) are present in about 70% of the whole seronegative (SN), who usually develop a severe disease with bulbar involvement. We surveyed a cohort of 175 OMG patients with purely ocular symptoms and we compare the outcome of patients with antibodies to AChR or to MuSK with those seronegative for both Abs (DSN). All patients had purely ocular signs for at least 24 months. Gender, age at onset, time to generalization or to worsening in quantitative ocular QMG scores, electrophysiological results were analyzed. Males were 58.9%, females 41.1%. Patients with late onset of symptoms after 50 years (LOMG) were 78.3%. We assayed anti-MuSK-Abs in 4.7%, anti-AChR Abs in 38.5%; 57.3% were defined DSN. Thirty-seven patients (21.1%) progressed to GMG during the observational time: 23 were females, 62% of the whole group of the generalized subjects, 75% of MuSK-positive OMG converted to GMG versus the 26.2% of AChR positive and 13.7% of DSN. Statistical analysis showed that gender and presence of antibodies either to AChR or to MuSK were independent predictors of worse outcome; the DSN subjects had lower risk of conversion to GMG.
Collapse
Affiliation(s)
- Giuliana Galassi
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy.
| | - Marco Mazzoli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Alessandra Ariatti
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Shaniko Kaleci
- Department of Diagnostic Clinical Medicine and Public Health, University of Modena, Modena, Italy
| | - Franco Valzania
- Department of Neurology, Arcispedale S. Maria Nuova, Reggio Emilia, Italy
| | - Paolo F Nichelli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| |
Collapse
|
32
|
Morren J, Li Y. Myasthenia gravis with muscle-specific tyrosine kinase antibodies: A narrative review. Muscle Nerve 2018; 58:344-358. [DOI: 10.1002/mus.26107] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/09/2018] [Accepted: 02/18/2018] [Indexed: 12/14/2022]
Affiliation(s)
- John Morren
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
| | - Yuebing Li
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
| |
Collapse
|
33
|
Park KH, Waters P, Woodhall M, Lang B, Smith T, Sung JJ, Kim KK, Lim YM, Kim JE, Kim BJ, Park JS, Lim JG, Kim DS, Kwon O, Sohn EH, Bae JS, Yoon BN, Kim NH, Ahn SW, Oh J, Park HJ, Shin KJ, Hong YH. Myasthenia gravis seronegative for acetylcholine receptor antibodies in South Korea: Autoantibody profiles and clinical features. PLoS One 2018. [PMID: 29518096 PMCID: PMC5843234 DOI: 10.1371/journal.pone.0193723] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acquired myasthenia gravis (MG) is a prototype autoimmune disease of the neuromuscular junction, caused in most patients by autoantibodies to the muscle nicotinic acetylcholine receptor (AChR). There seem to be ethnic and regional differences in the frequency and clinical features of MG seronegative for the AChR antibody. This study aimed to describe the autoantibody profiles and clinical features of Korean patients with generalized MG seronegative for the AChR antibody. A total of 62 patients with a high index of clinical suspicion of seronegative generalized MG were identified from 18 centers, and we examined their sera for antibodies to clustered AChR, muscle-specific tyrosine kinase (MuSK), and low-density lipoprotein receptor-related protein 4 (LRP4) by cell-based assays (CBA) and to MuSK by radioimmunoprecipitation assay (RIPA). We also included 8 patients with ocular MG, 3 with Lambert-Eaton myasthenic syndrome, 5 with motor neuron disease, and 9 with other diagnoses as comparators for the serological testing. Antibodies were identified in 25/62 (40.3%) patients: 7 had antibodies to clustered AChR, 17 to MuSK, and 2 to LRP4. Three patients were double seropositive: 1 for MuSK and LRP4, and 2 for MuSK and clustered AChR. The patients with MuSK antibodies were mostly female (88.2%) and characterized by predominantly bulbar involvement (70%) and frequent myasthenic crises (58.3%). The patients with antibodies to clustered AChR, including 2 with ocular MG, tended to have a mild phenotype and good prognosis.
Collapse
Affiliation(s)
- Kee Hong Park
- Department of Neurology, Gyeongsang National University Hospital, Jinju, Republic of Korea
| | - Patrick Waters
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
- * E-mail: (YHH); (PW)
| | - Mark Woodhall
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Bethan Lang
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Thomas Smith
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jung-Joon Sung
- Department of Neurology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Kwang-Kuk Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Young-Min Lim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jee-Eun Kim
- Department of Neurology, Seoul Medical Center, Seoul, Republic of Korea
| | - Byung-Jo Kim
- Department of Neurology, Korea University College of Medicine, Korea University Anam Hospital, Seoul, Republic of Korea
| | - Jin-Sung Park
- Department of Neurology, Kyungpook National University, School of Medicine, Daegu, Republic of Korea
| | - Jeong-Geon Lim
- Department of Neurology, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Ohyun Kwon
- Department of Neurology, School of Medicine, Eulji University, Seoul, Republic of Korea
| | - Eun Hee Sohn
- Department of Neurology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Jong Seok Bae
- Department of Neurology, College of Medicine, Hallym University, Seoul, Republic of Korea
| | - Byung-Nam Yoon
- Department of Neurology, Inha University Hospital, Incheon, Republic of Korea
| | - Nam-Hee Kim
- Department of Neurology, Dongguk University Ilsan Hospital, Goyangsi, Gyeonggido, Republic of Korea
| | - Suk-Won Ahn
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Jeeyoung Oh
- Department of Neurology, Konkuk University Medical Center, Seoul, Republic of Korea
| | - Hyung Jun Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Republic of Korea
| | - Kyong Jin Shin
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Yoon-Ho Hong
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Seoul Metropolitan Government Boramae Medical Center, Seoul National University Medical Research Council, Seoul, Republic of Korea
- * E-mail: (YHH); (PW)
| |
Collapse
|
34
|
Anti-MuSK positivity on plasmapheresis liquid in a double seronegative myasthenia gravis patient. Acta Neurol Belg 2018; 118:119-120. [PMID: 28608313 DOI: 10.1007/s13760-017-0806-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/04/2017] [Indexed: 10/19/2022]
|
35
|
Autoantibodies to Low-Density Lipoprotein Receptor-Related Protein 4 in Double Seronegative Myasthenia Gravis: A Systematic Review. Can J Neurol Sci 2017; 45:62-67. [DOI: 10.1017/cjn.2017.253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractBackground: Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction in which a clinical diagnosis may be confirmed with serological testing. The most common autoantibodies used to support a diagnosis of MG are anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies. In cases in which both of these autoantibodies are negative (termed double-seronegative [dSNMG]), other autoantibodies such as low-density lipoprotein receptor-related protein 4 (LRP4) may be used to aid in diagnosis. Methods: We have undertaken a systematic literature review to identify studies that have assessed the frequency of anti-LRP4 antibodies in dSNMG patients and the characteristics of anti-LRP4+ dSNMG patients (epidemiology, clinical features, electromyographic findings, or management). PubMed, EMBASE, Medline, and Scopus were searched on January 14, 2017, using the medical subject headings “myasthenia gravis” and “low-density lipoprotein receptor-related protein 4” or “LRP4.” Results: The initial search identified 367 articles. Fourteen publications met the inclusion criteria. There were ten cross-sectional research studies, three were case series, and one was a case report. The majority of studies were limited by small sample sizes of LRP4+ dSNMG. There has been a wide range of frequencies of anti-LRP4 antibodies detected in different MG patient populations, some involving different laboratory techniques. Conclusions: LRP4+ dSNMG is more likely than LRP4– dSNMG to have a younger onset of disease and occur in females. LRP4+ dSNMG most often is mild in severity and often involves isolated ocular weakness. It typically responds well to pyridostigmine or prednisone.
Collapse
|
36
|
Stathopoulos P, Kumar A, Nowak RJ, O'Connor KC. Autoantibody-producing plasmablasts after B cell depletion identified in muscle-specific kinase myasthenia gravis. JCI Insight 2017; 2:94263. [PMID: 28878127 DOI: 10.1172/jci.insight.94263] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/25/2017] [Indexed: 12/24/2022] Open
Abstract
Myasthenia gravis (MG) is a B cell-mediated autoimmune disorder of neuromuscular transmission. Pathogenic autoantibodies to muscle-specific tyrosine kinase (MuSK) can be found in patients with MG who do not have detectable antibodies to the acetylcholine receptor (AChR). MuSK MG includes immunological and clinical features that are generally distinct from AChR MG, particularly regarding responsiveness to therapy. B cell depletion has been shown to affect a decline in serum autoantibodies and to induce sustained clinical improvement in the majority of MuSK MG patients. However, the duration of this benefit may be limited, as we observed disease relapse in MuSK MG patients who had achieved rituximab-induced remission. We investigated the mechanisms of such relapses by exploring autoantibody production in the reemerging B cell compartment. Autoantibody-expressing CD27+ B cells were observed within the reconstituted repertoire during relapse but not during remission or in controls. Using two complementary approaches, which included production of 108 unique human monoclonal recombinant immunoglobulins, we demonstrated that antibody-secreting CD27hiCD38hi B cells (plasmablasts) contribute to the production of MuSK autoantibodies during relapse. The autoantibodies displayed hallmarks of antigen-driven affinity maturation. These collective findings introduce potential mechanisms for understanding both MuSK autoantibody production and disease relapse following B cell depletion.
Collapse
|
37
|
Romi F, Hong Y, Gilhus NE. Pathophysiology and immunological profile of myasthenia gravis and its subgroups. Curr Opin Immunol 2017; 49:9-13. [PMID: 28780294 DOI: 10.1016/j.coi.2017.07.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/07/2017] [Indexed: 01/11/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune antibody-mediated disease characterized by muscle weakness and fatigability. It is believed that the initial steps triggering humoral immunity in MG take place inside thymic tissue and thymoma. The immune response against one or several epitopes expressed on thymic tissue cells spills over to neuromuscular junction components sharing the same epitope causing humoral autoimmunity and antibody production. The main cause of MG is acetylcholine receptor antibodies. However, many other neuromuscular junction membrane protein targets, intracellular and extracellular proteins are suggested to participate in MG pathophysiology. MG should be divided into subgroups based on clinical presentation and immunology. This includes onset age, clinical characteristics, thymic pathology and antibody profile. The immunological profile of these subgroups is determined by the antibodies present.
Collapse
Affiliation(s)
- Fredrik Romi
- Department of Neurology, Haukeland University Hospital, Norway.
| | - Yu Hong
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Nils Erik Gilhus
- Department of Neurology, Haukeland University Hospital, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway
| |
Collapse
|
38
|
Huda S, Waters P, Woodhall M, Leite MI, Jacobson L, De Rosa A, Maestri M, Ricciardi R, Heckmann JM, Maniaol A, Evoli A, Cossins J, Hilton-Jones D, Vincent A. IgG-specific cell-based assay detects potentially pathogenic MuSK-Abs in seronegative MG. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2017; 4:e357. [PMID: 28626780 PMCID: PMC5459793 DOI: 10.1212/nxi.0000000000000357] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 04/06/2017] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To increase the detection of MuSK-Abs using a CBA and test their pathogenicity. METHODS Sera from 69 MuSK-RIA-positive patients with myasthenia gravis (MG) (Definite MuSK-MG), 169 patients negative for MuSK-RIA and AChR-RIA (seronegative MG, SNMG), 35 healthy individuals (healthy controls, HCs), and 16 NMDA receptor-Ab-positive (NMDAR-Ab) disease controls were tested for binding to MuSK on a CBA using different secondary antibodies. RESULTS Initially, in addition to 18% of SNMG sera, 11% of HC and 19% of NMDAR-Ab sera showed positive binding to MuSK-transfected cells; this low specificity was due to anti-IgG(H+L) detection of IgM bound nonspecifically to MuSK. Using an IgG Fc gamma-specific secondary antibody, MuSK-Abs were detected by CBA in 68/69 (99%) of Definite MuSK-MG, 0/35 HCs, 0/16 NMDAR-Ab, and 14/169 (8%) of SNMG sera, providing increased sensitivity with high specificity. The RIA-negative, CBA-positive MuSK-IgG sera, but not IgM-MuSK-binding sera, reduced agrin-induced AChR clustering in C2C12 myotubes, qualitatively similar to RIA-positive MuSK-Abs. CONCLUSIONS An IgG-specific MuSK-CBA can reliably detect IgG MuSK-Abs and increase sensitivity. In the MuSK-CBA, IgG specificity is essential. The positive sera demonstrated pathogenic potential in the in vitro AChR-clustering assay, although less effective than Definite MuSK-MG sera, and the patients had less severe clinical disease. Use of IgG-specific secondary antibodies may improve the results of other antibody tests. CLASSIFICATION OF EVIDENCE This study provides Class III evidence that an IgG-specific MuSK-CBA identifies patients with MG.
Collapse
Affiliation(s)
- Saif Huda
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Patrick Waters
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Mark Woodhall
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Maria Isabel Leite
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Leslie Jacobson
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Anna De Rosa
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Michelangelo Maestri
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Roberta Ricciardi
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Jeannine M Heckmann
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Angelina Maniaol
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Amelia Evoli
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Judy Cossins
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - David Hilton-Jones
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences (S.H., P.W., M.W., M.I.L., L.J., J.C., D.H.-J., A.V.), University of Oxford, UK; Department of Clinical and Experimental Medicine (A.D.R., M.M., R.R.), Neurology Unit, Pisa, Italy; Division of Neurology (J.M.H.), University of Cape Town, South Africa; Oslo University Hospital (A.M.), Norway; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| |
Collapse
|
39
|
Cordts I, Bodart N, Hartmann K, Karagiorgou K, Tzartos JS, Mei L, Reimann J, Van Damme P, Rivner MH, Vigneron A, Weis J, Schulz JB, Tzartos SJ, Claeys KG. Screening for lipoprotein receptor-related protein 4-, agrin-, and titin-antibodies and exploring the autoimmune spectrum in myasthenia gravis. J Neurol 2017; 264:1193-1203. [DOI: 10.1007/s00415-017-8514-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/24/2017] [Accepted: 05/08/2017] [Indexed: 01/09/2023]
|
40
|
Hong Y, Zisimopoulou P, Trakas N, Karagiorgou K, Stergiou C, Skeie GO, Hao HJ, Gao X, Owe JF, Zhang X, Yue YX, Romi F, Wang Q, Li HF, Gilhus NE, Tzartos SJ. Multiple antibody detection in ‘seronegative’ myasthenia gravis patients. Eur J Neurol 2017; 24:844-850. [PMID: 28470860 DOI: 10.1111/ene.13300] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/23/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Y. Hong
- Department of Clinical Medicine; University of Bergen; Bergen Norway
| | - P. Zisimopoulou
- Department of Neurobiology; Hellenic Pasteur Institute; Athens Greece
| | - N. Trakas
- Department of Neurobiology; Hellenic Pasteur Institute; Athens Greece
| | - K. Karagiorgou
- Department of Neurobiology; Hellenic Pasteur Institute; Athens Greece
- Tzartos NeuroDiagnostics; Athens Greece
| | - C. Stergiou
- Department of Neurobiology; Hellenic Pasteur Institute; Athens Greece
- Tzartos NeuroDiagnostics; Athens Greece
| | - G. O. Skeie
- Department of Neurology; Haukeland University Hospital; Bergen Norway
| | - H.-J. Hao
- Department of Neurology; Peking University First Hospital; Beijing China
| | - X. Gao
- Department of Neurology; Affiliated Hospital of Qingdao University; Qingdao China
| | - J. F. Owe
- Department of Neurology; Haukeland University Hospital; Bergen Norway
| | - X. Zhang
- Department of Neurology; Affiliated Hospital of Qingdao University; Qingdao China
| | - Y.-X. Yue
- Department of Neurology; Qilu Hospital of Shandong University; Jinan China
| | - F. Romi
- Department of Clinical Medicine; University of Bergen; Bergen Norway
- Department of Neurology; Haukeland University Hospital; Bergen Norway
| | - Q. Wang
- Department of Neurology; Affiliated Hospital of Qingdao University; Qingdao China
| | - H.-F. Li
- Department of Neurology; Qilu Hospital of Shandong University; Jinan China
| | - N. E. Gilhus
- Department of Clinical Medicine; University of Bergen; Bergen Norway
- Department of Neurology; Haukeland University Hospital; Bergen Norway
| | - S. J. Tzartos
- Department of Neurobiology; Hellenic Pasteur Institute; Athens Greece
- Tzartos NeuroDiagnostics; Athens Greece
- University of Patras; Patras Greece
| |
Collapse
|
41
|
Hong Y, Skeie GO, Zisimopoulou P, Karagiorgou K, Tzartos SJ, Gao X, Yue YX, Romi F, Zhang X, Li HF, Gilhus NE. Juvenile-onset myasthenia gravis: autoantibody status, clinical characteristics and genetic polymorphisms. J Neurol 2017; 264:955-962. [PMID: 28364296 DOI: 10.1007/s00415-017-8478-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 01/10/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder mediated by antibodies against proteins at the neuromuscular junction. Juvenile-onset MG (JMG) has been reported to have special characteristics. It is still unclear whether there are any pathogenic and genetic differences between juvenile and adult MG. In this study, we evaluated the clinical characteristics, autoantibody status (antibodies against AChR, MuSK, LRP4, titin and RyR) and genetic susceptibility (CHRNA1, CTLA4 and AIRE) in 114 Chinese JMG patients, and compared with 207 young adult MG patients (onset age 18-40 years). JMG patients were classified into two subgroups: the very early onset group (<8 years) and puberty onset group (8-18 years). The very early onset MG patients had a higher proportion of ocular MG and thymus hyperplasia, compared with puberty onset MG and young adult MG (P < 0.05). AChR antibodies were found in majority of JMG patients and were associated with more severe disease (P < 0.05), while other antibodies were rare in JMG. Moreover, the very early onset MG had a more prominent genetic predisposition than puberty and adult MG, affecting the susceptible genes CHRNA1 and CTLA4. JMG has the same pathogenic background as adult MG, but has typical clinical features and a prominent genetic predisposition in very early onset patients (<8 years). Specific therapeutic considerations are needed.
Collapse
Affiliation(s)
- Yu Hong
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Geir Olve Skeie
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
| | | | - Katerina Karagiorgou
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Tzartos NeuroDiagnostics, Athens, Greece
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Tzartos NeuroDiagnostics, Athens, Greece
| | - Xiang Gao
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yao-Xian Yue
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Fredrik Romi
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
| | - Xu Zhang
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hai-Feng Li
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China.
| | - Nils Erik Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway.
| |
Collapse
|
42
|
Rozmilowska I, Adamczyk-Sowa M, Rutkowska K, Pierzchala K, Misiolek H. Improvement of quality of life after therapeutic plasma exchange in patients with myasthenic crisis. Neurol Neurochir Pol 2016; 50:418-424. [PMID: 27491460 DOI: 10.1016/j.pjnns.2016.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/18/2016] [Accepted: 07/20/2016] [Indexed: 11/19/2022]
Abstract
INTRODUCTION We sought to evaluate quality of life patients with myasthenic crisis before and after therapeutic plasma exchange. MATERIALS AND METHODS In our study we conducted an assessment of the quality of life with the use of the questionnaire SF-36, when executed eleven therapeutic plasma exchange. The assessment was made on baseline and after 4 weeks. We also did neurological clinical evaluation before and after TPE. RESULTS Patients in the study showed significant improvement in quality of life after performed therapeutic plasma exchange. The changes were observed in physical functioning, which confirmed the results of the statistical significance of p<0.05. In the analysis, the assessment of mental functioning not obtained the results of statistical significance, but the results also showed improvement in self-assessment. We observed high correlation between general health and physical mental functioning, between the role limitations due to physical health problems and role limitations due to emotional problems, and general health perception and bodily pain. CONCLUSIONS Therapeutic plasma exchange significantly improves the quality of life of patients with myasthenia gravis during the crisis.
Collapse
Affiliation(s)
- Izabela Rozmilowska
- Department of Neurology in Zabrze, Medical University of Silesia, Zabrze, Poland.
| | - Monika Adamczyk-Sowa
- Department of Neurology in Zabrze, Medical University of Silesia, Zabrze, Poland
| | - Katarzyna Rutkowska
- Department of Anesthesiology and Intensive Therapy, Medical University of Silesia, Katowice, Poland
| | - Krystyna Pierzchala
- Department of Neurology in Zabrze, Medical University of Silesia, Zabrze, Poland
| | - Hanna Misiolek
- Department of Anesthesiology and Intensive Therapy, Medical University of Silesia, Katowice, Poland
| |
Collapse
|
43
|
Huda S, Woodhall MR, Vincent A, Heckmann JM. Characteristics Of acetylcholine-receptor-antibody-negative myasthenia gravis in a South African cohort. Muscle Nerve 2016; 54:1023-1029. [PMID: 27105303 DOI: 10.1002/mus.25154] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/16/2016] [Accepted: 04/20/2016] [Indexed: 11/10/2022]
Abstract
INTRODUCTION In this study we determined the frequencies of antibodies (Abs) directed against muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4) in the sera of a South African cohort with acetylcholine receptor (AChR)-antibody-negative generalized MG and determined outcomes to therapies. METHODS Sera negative by commercial AChR radioimmunoassay (RIA) were tested by MuSK RIA (n = 30; 2006-2012) and AChR, MuSK, and LRP4 RIA with or without cell-based assays (CBA) (n = 53; 2012-2015). RESULTS AChR-Abs were detected in 4 of 53 and MuSK-Abs in 20 of 83 (24%) cases. Thirty-six of 53 (68%) were triple seronegative (triple-SNMG) for MuSK, AChR, and LRP4-Abs. When compared with triple-SNMG, individuals with MuSK-MG had a younger onset age (P = 0.008), a greater likelihood of African genetic ancestry (P = 0.008), and 4-fold higher odds of reaching MGFA grade IVB/V (P = 0.018), but were also 9-fold more likely to reach at least minimal manifestations status after ≥12 months of therapy (P = 0.003). CONCLUSIONS Individuals with African genetic ancestry and severe bulbar/respiratory AChR-Ab-negative MG are likely to have MuSK-MG, but most respond favorably to maintenance immunotherapies. Muscle Nerve 54: 1023-1029, 2016.
Collapse
Affiliation(s)
- Saif Huda
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Mark R Woodhall
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jeannine M Heckmann
- Division of Neurology, E8-74, Department of Medicine, University of Cape Town, South Africa
| |
Collapse
|
44
|
Lee JI, Jander S. Myasthenia gravis: recent advances in immunopathology and therapy. Expert Rev Neurother 2016; 17:287-299. [PMID: 27690672 DOI: 10.1080/14737175.2017.1241144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- John-Ih Lee
- Department of Neurology, Heinrich-Heine-University, Medical Faculty, Duesseldorf, Germany
| | - Sebastian Jander
- Department of Neurology, Heinrich-Heine-University, Medical Faculty, Duesseldorf, Germany
| |
Collapse
|
45
|
Hurst RL, Gooch CL. Muscle-Specific Receptor Tyrosine Kinase (MuSK) Myasthenia Gravis. Curr Neurol Neurosci Rep 2016; 16:61. [DOI: 10.1007/s11910-016-0668-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
46
|
Li HF, Hong Y, Xie Y, Hao HJ, Sun RC. Precision medicine in myasthenia graves: begin from the data precision. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:106. [PMID: 27127759 DOI: 10.21037/atm.2016.02.16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Myasthenia gravis (MG) is a prototypic autoimmune disease with overt clinical and immunological heterogeneity. The data of MG is far from individually precise now, partially due to the rarity and heterogeneity of this disease. In this review, we provide the basic insights of MG data precision, including onset age, presenting symptoms, generalization, thymus status, pathogenic autoantibodies, muscle involvement, severity and response to treatment based on references and our previous studies. Subgroups and quantitative traits of MG are discussed in the sense of data precision. The role of disease registries and scientific bases of precise analysis are also discussed to ensure better collection and analysis of MG data.
Collapse
Affiliation(s)
- Hai-Feng Li
- 1 Department of Neurology, Qilu Hospital of Shandong University, Jinan 250012, China ; 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway ; 3 Department of Neurology, The George Washington University, Washington, DC, USA ; 4 Department of Neurology, Peking University First Hospital, Beijing 100034, China ; 5 College of Information and Engineering, Qingdao University, Qingdao 266071, China
| | - Yu Hong
- 1 Department of Neurology, Qilu Hospital of Shandong University, Jinan 250012, China ; 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway ; 3 Department of Neurology, The George Washington University, Washington, DC, USA ; 4 Department of Neurology, Peking University First Hospital, Beijing 100034, China ; 5 College of Information and Engineering, Qingdao University, Qingdao 266071, China
| | - Yanchen Xie
- 1 Department of Neurology, Qilu Hospital of Shandong University, Jinan 250012, China ; 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway ; 3 Department of Neurology, The George Washington University, Washington, DC, USA ; 4 Department of Neurology, Peking University First Hospital, Beijing 100034, China ; 5 College of Information and Engineering, Qingdao University, Qingdao 266071, China
| | - Hong-Jun Hao
- 1 Department of Neurology, Qilu Hospital of Shandong University, Jinan 250012, China ; 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway ; 3 Department of Neurology, The George Washington University, Washington, DC, USA ; 4 Department of Neurology, Peking University First Hospital, Beijing 100034, China ; 5 College of Information and Engineering, Qingdao University, Qingdao 266071, China
| | - Ren-Cheng Sun
- 1 Department of Neurology, Qilu Hospital of Shandong University, Jinan 250012, China ; 2 Department of Clinical Medicine, University of Bergen, Bergen, Norway ; 3 Department of Neurology, The George Washington University, Washington, DC, USA ; 4 Department of Neurology, Peking University First Hospital, Beijing 100034, China ; 5 College of Information and Engineering, Qingdao University, Qingdao 266071, China
| |
Collapse
|
47
|
Myasthenia gravis — autoantibody characteristics and their implications for therapy. Nat Rev Neurol 2016; 12:259-68. [DOI: 10.1038/nrneurol.2016.44] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
48
|
Stergiou C, Lazaridis K, Zouvelou V, Tzartos J, Mantegazza R, Antozzi C, Andreetta F, Evoli A, Deymeer F, Saruhan-Direskeneli G, Durmus H, Brenner T, Vaknin A, Berrih-Aknin S, Behin A, Sharshar T, De Baets M, Losen M, Martinez-Martinez P, Kleopa KA, Zamba-Papanicolaou E, Kyriakides T, Kostera-Pruszczyk A, Szczudlik P, Szyluk B, Lavrnic D, Basta I, Peric S, Tallaksen C, Maniaol A, Gilhus NE, Casasnovas Pons C, Pitha J, Jakubíkova M, Hanisch F, Bogomolovas J, Labeit D, Labeit S, Tzartos SJ. Titin antibodies in "seronegative" myasthenia gravis--A new role for an old antigen. J Neuroimmunol 2016; 292:108-15. [PMID: 26943968 DOI: 10.1016/j.jneuroim.2016.01.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 12/11/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction of skeletal muscles. Triple-seronegative MG (tSN-MG, without detectable AChR, MuSK and LRP4 antibodies), which accounts for ~10% of MG patients, presents a serious gap in MG diagnosis and complicates differential diagnosis of similar disorders. Several AChR antibody positive patients (AChR-MG) also have antibodies against titin, usually detected by ELISA. We have developed a very sensitive radioimmunoprecipitation assay (RIPA) for titin antibodies, by which many previously negative samples were found positive, including several from tSN-MG patients. The validity of the RIPA results was confirmed by western blots. Using this RIPA we screened 667 MG sera from 13 countries; as expected, AChR-MG patients had the highest frequency of titin antibodies (40.9%), while MuSK-MG and LRP4-MG patients were positive in 14.6% and 16.4% respectively. Most importantly, 13.4% (50/372) of the tSN-MG patients were also titin antibody positive. None of the 121 healthy controls or the 90 myopathy patients, and only 3.6% (7/193) of other neurological disease patients were positive. We thus propose that the present titin antibody RIPA is a useful tool for serological MG diagnosis of tSN patients.
Collapse
Affiliation(s)
- C Stergiou
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece
| | | | - V Zouvelou
- Neurology Department, Aeginition Hospital, Athens, Greece
| | - J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece
| | - R Mantegazza
- Neurological Institute "C. Besta", Milano, Italy
| | - C Antozzi
- Neurological Institute "C. Besta", Milano, Italy
| | - F Andreetta
- Neurological Institute "C. Besta", Milano, Italy
| | - A Evoli
- Institute of Neurology, Catholic University, Rome, Italy
| | - F Deymeer
- Istanbul University, Istanbul, Turkey
| | | | - H Durmus
- Istanbul University, Istanbul, Turkey
| | - T Brenner
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - A Vaknin
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | | | - A Behin
- UPMC and INSERM, Paris, France
| | - T Sharshar
- Raymond Poincaré Hospital, Garches, France
| | - M De Baets
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - M Losen
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - P Martinez-Martinez
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - K A Kleopa
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - T Kyriakides
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - P Szczudlik
- Department of Neurology, Medical University of Warsaw, Poland
| | - B Szyluk
- Department of Neurology, Medical University of Warsaw, Poland
| | - D Lavrnic
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - I Basta
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - S Peric
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - C Tallaksen
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway; Faculty of Medicine, Olso University, Norway
| | - A Maniaol
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway
| | - N E Gilhus
- Department of Clinical Medicine, University of Bergen, Norway
| | | | - J Pitha
- Department of Neurology and Clinical Neuroscience Center, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Prague, Czech Republic
| | - M Jakubíkova
- Department of Neurology and Clinical Neuroscience Center, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Prague, Czech Republic
| | - F Hanisch
- Universitätsklinikum Halle, Halle, Germany
| | - J Bogomolovas
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany
| | - D Labeit
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany; Myomedix GmbH, 69151 Neckargemuend, Germany
| | - S Labeit
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany
| | - S J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece.
| |
Collapse
|
49
|
Binks S, Vincent A, Palace J. Myasthenia gravis: a clinical-immunological update. J Neurol 2015; 263:826-34. [PMID: 26705120 PMCID: PMC4826656 DOI: 10.1007/s00415-015-7963-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022]
Abstract
Myasthenia gravis (MG) is the archetypic disorder of both the neuromuscular junction and autoantibody-mediated disease. In most patients, IgG1-dominant antibodies to acetylcholine receptors cause fatigable weakness of skeletal muscles. In the rest, a variable proportion possesses antibodies to muscle-specific tyrosine kinase while the remainder of seronegative MG is being explained through cell-based assays using a receptor-clustering technique and, to a lesser extent, proposed new antigenic targets. The incidence and prevalence of MG are increasing, particularly in the elderly. New treatments are being developed, and results from the randomised controlled trial of thymectomy in non-thymomatous MG, due for release in early 2016, will be of particular clinical value. To help navigate an evidence base of varying quality, practising clinicians may consult new MG guidelines in the fields of pregnancy, ocular and generalised MG (GMG). This review focuses on updates in epidemiology, immunology, therapeutic and clinical aspects of GMG in adults.
Collapse
Affiliation(s)
- Sophie Binks
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
| |
Collapse
|
50
|
Hu B, Simon-Keller K, Küffer S, Ströbel P, Braun T, Marx A, Porubsky S. Myf5 and Myogenin in the development of thymic myoid cells - Implications for a murine in vivo model of myasthenia gravis. Exp Neurol 2015; 277:76-85. [PMID: 26708556 DOI: 10.1016/j.expneurol.2015.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 11/24/2015] [Accepted: 12/15/2015] [Indexed: 01/24/2023]
Abstract
Myasthenia gravis (MG) is caused by autoantibodies against the neuromuscular junction of striated muscle. Most MG patients have autoreactive T- and B-cells directed to the acetylcholine receptor (AChR). To achieve immunologic tolerance, developing thymocytes are normally eliminated after recognition of self-antigen-derived peptides. Presentation of muscle-specific antigens is likely achieved through two pathways: on medullary thymic epithelial cells and on medullary dendritic cells cross-presenting peptides derived from a unique population of thymic myoid cells (TMC). Decades ago, it has been hypothesized that TMC play a key role in the induction of immunological tolerance towards skeletal muscle antigens. However, an experimental model to address this postulate has not been available. To generate such a model, we tested the hypothesis that the development of TMC depends on myogenic regulatory factors. To this end, we utilized Myf5-deficient mice, which lack the first wave of muscle cells but form normal skeletal muscles later during development, and Myogenin-deficient mice, which fail to form differentiated myofibers. We demonstrate for the first time that Myf5- and Myogenin-deficient mice showed a partial or complete, respectively, loss of TMC in an otherwise regularly structured thymus. To overcome early postnatal lethality of muscle-deficient, Myogenin-knockout mice we transplanted Myogenin-deficient fetal thymuses into Foxn1(nu/nu) mice that lack their own thymus anlage. We found that the transplants are functional but lack TMC. In combination with established immunization strategies (utilizing AChR or Titin), this model should enable us in the future testing the hypothesis that TMC play an indispensable role in the development of central tolerance towards striated muscle antigens.
Collapse
Affiliation(s)
- Bo Hu
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Katja Simon-Keller
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Stefan Küffer
- Institute of Pathology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Philipp Ströbel
- Institute of Pathology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Thomas Braun
- Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany
| | - Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Stefan Porubsky
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| |
Collapse
|