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2.
Brain Nerve ; 76(5): 613-620, 2024 May.
Artículo en Japonés | MEDLINE | ID: mdl-38741504

RESUMEN

Herein, we describe the mechanisms, diagnostic procedures, and treatment options for acetylcholine receptor (AChR) antibody-positive myasthenia gravis (MG). The upstream pathomechanism of this condition involves AChR-sensitized T cell-dependent B cell proliferation and the subsequent production of pathogenic autoantibodies. Downstream molecules include AChR antibodies that activate complement pathways, resulting in the destruction of motor endplates. We further introduce newly-developed molecular targeted drugs for the treatment of MG that aims to secure patients' health-related quality of life.


Asunto(s)
Autoanticuerpos , Miastenia Gravis , Receptores Colinérgicos , Miastenia Gravis/inmunología , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Humanos , Receptores Colinérgicos/inmunología , Autoanticuerpos/inmunología
3.
Brain Nerve ; 76(5): 623-629, 2024 May.
Artículo en Japonés | MEDLINE | ID: mdl-38741505

RESUMEN

Reportedly, patients with muscle-specific kinase (MuSK) antibody-positive myasthenia gravis (MG) account for approximately 3.0% of all patients with MG in Japan. Compared with patients who have acetylcholine receptor antibody-positive MG, those with MuSK antibody-positive MG show young-onset disease with female predominance, a low rate of ocular involvement (5.9%), and greater severity of dysphagia. The aforementioned types of MG are indistinguishable based on clinical symptoms and electrophysiological tests, and measurement of MuSK antibodies is essential for diagnosis. Thymectomy and complement inhibitors are not indicated for treatment, and acetylcholinesterase inhibitors, steroids, immunosuppressants, plasma exchange, intravenous immunoglobulin therapy, and neonatal Fc receptor inhibitors are used.


Asunto(s)
Autoanticuerpos , Miastenia Gravis , Proteínas Tirosina Quinasas Receptoras , Receptores Colinérgicos , Humanos , Miastenia Gravis/inmunología , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Proteínas Tirosina Quinasas Receptoras/inmunología , Receptores Colinérgicos/inmunología , Autoanticuerpos/inmunología
4.
Front Immunol ; 15: 1382320, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38711503

RESUMEN

Myasthenia gravis (MG), primarily caused by acetylcholine receptor (AChR) autoantibodies, is a chronic autoimmune disorder causing severe muscle weakness and fatigability. In particular, seronegative MG constitutes 10%-15% of MG cases and presents diagnostic challenges especially in early-onset female patients who often show severe disease and resistance to immunosuppressive therapy. Furthermore, the immunopathology of seronegative MG remains unclear. Thus, in this study, we aimed to elucidate the pathogenic mechanism of seronegative MG using scRNA-seq analysis and plasma proteome analysis; in particular, we investigated the relationship between immune dysregulation status and disease severity in refractory seronegative MG. Employing single-cell RNA-sequencing and plasma proteome analyses, we analyzed peripheral blood samples from 30 women divided into three groups: 10 healthy controls, 10 early-onset AChR-positive MG, and 10 refractory early-onset seronegative MG patients, both before and after intravenous immunoglobulin treatment. The disease severity was evaluated using the MG-Activities of Daily Living (ADL), MG composite (MGC), and revised 15-item MG-Quality of Life (QOL) scales. We observed numerical abnormalities in multiple immune cells, particularly B cells, in patients with refractory seronegative MG, correlating with disease activity. Notably, severe MG cases had fewer regulatory T cells without functional abnormalities. Memory B cells were found to be enriched in peripheral blood cells compared with naïve B cells. Moreover, plasma proteome analysis indicated significantly lower plasma protein levels of soluble CD22, expressed in the lineage of B-cell maturation (including mature B cells and memory B cells), in refractory seronegative MG patients than in healthy donors or patients with AChR-positive MG. Soluble CD22 levels were correlated with disease severity, B-cell frequency, and RNA expression levels of CD22. In summary, this study elucidates the immunopathology of refractory seronegative MG, highlighting immune disorders centered on B cells and diminished soluble CD22 levels. These insights pave the way for novel MG treatment strategies focused on B-cell biology.


Asunto(s)
Linfocitos B , Miastenia Gravis , Lectina 2 Similar a Ig de Unión al Ácido Siálico , Humanos , Miastenia Gravis/inmunología , Miastenia Gravis/sangre , Femenino , Adulto , Linfocitos B/inmunología , Lectina 2 Similar a Ig de Unión al Ácido Siálico/inmunología , Persona de Mediana Edad , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Inmunoglobulinas Intravenosas/uso terapéutico , Receptores Colinérgicos/inmunología , Índice de Severidad de la Enfermedad , Adulto Joven , Proteoma
5.
Front Immunol ; 15: 1325171, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38715598

RESUMEN

Introduction: Muscle-specific kinase (MuSK)- myasthenia gravis (MG) is caused by pathogenic autoantibodies against MuSK that correlate with disease severity and are predominantly of the IgG4 subclass. The first-line treatment for MuSK-MG is general immunosuppression with corticosteroids, but the effect of treatment on IgG4 and MuSK IgG4 levels has not been studied. Methods: We analyzed the clinical data and sera from 52 MuSK-MG patients (45 female, 7 male, median age 49 (range 17-79) years) from Italy, the Netherlands, Greece and Belgium, and 43 AChR-MG patients (22 female, 21 male, median age 63 (range 2-82) years) from Italy, receiving different types of immunosuppression, and sera from 46 age- and sex-matched non-disease controls (with no diagnosed diseases, 38 female, 8 male, median age 51.5 (range 20-68) years) from the Netherlands. We analyzed the disease severity (assessed by MGFA or QMG score), and measured concentrations of MuSK IgG4, MuSK IgG, total IgG4 and total IgG in the sera by ELISA, RIA and nephelometry. Results: We observed that MuSK-MG patients showed a robust clinical improvement and reduction of MuSK IgG after therapy, and that MuSK IgG4 concentrations, but not total IgG4 concentrations, correlated with clinical severity. MuSK IgG and MuSK IgG4 concentrations were reduced after immunosuppression in 4/5 individuals with before-after data, but data from non-linked patient samples showed no difference. Total serum IgG4 levels were within the normal range, with IgG4 levels above threshold (1.35g/L) in 1/52 MuSK-MG, 2/43 AChR-MG patients and 1/45 non-disease controls. MuSK-MG patients improved within the first four years after disease onset, but no further clinical improvement or reduction of MuSK IgG4 were observed four years later, and only 14/52 (26.92%) patients in total, of which 13 (93.3%) received general immunosuppression, reached clinical remission. Discussion: We conclude that MuSK-MG patients improve clinically with general immunosuppression but may require further treatment to reach remission. Longitudinal testing of individual patients may be clinically more useful than single measurements of MuSK IgG4. No significant differences in the serum IgG4 concentrations and IgG4/IgG ratio between AChR- and MuSK-MG patients were found during follow-up. Further studies with larger patient and control cohorts are necessary to validate the findings.


Asunto(s)
Autoanticuerpos , Inmunoglobulina G , Miastenia Gravis , Proteínas Tirosina Quinasas Receptoras , Receptores Colinérgicos , Humanos , Miastenia Gravis/inmunología , Miastenia Gravis/sangre , Miastenia Gravis/diagnóstico , Masculino , Persona de Mediana Edad , Femenino , Adulto , Anciano , Proteínas Tirosina Quinasas Receptoras/inmunología , Receptores Colinérgicos/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Estudios Retrospectivos , Adulto Joven , Adolescente , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Anciano de 80 o más Años , Terapia de Inmunosupresión , Inmunosupresores/uso terapéutico , Índice de Severidad de la Enfermedad , Niño
6.
J Neuromuscul Dis ; 11(3): 613-623, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38578899

RESUMEN

Background/Objective: Myasthenia Gravis (MG) is an autoimmune disorder characterized by pathogenic autoantibodies (AAbs) targeting nicotinic acetylcholine receptors (AChR), disrupting neuromuscular communication. RadioImmunoPrecipitation Assay (RIPA) is recommended to detect AChR AAbs, but its complexity and radioactive requirements limit widespread use. We compare non-RIPA anti-AChR immunoassays, including Cell-Based Assay (CBA) and two ELISA kits, against the gold standard RIPA. Methods/Results: 145 samples were included with medical indication for anti-AChR testing. By the RIPA method, 63 were negative (RIPA-Neg < 0.02 nmol/L), 18 were classified as Borderline (≥0.02 -1 nmol/L), and 64 were positive (RIPA-Pos > 1 nmol/L). The competitive ELISA showed poor agreement with RIPA (Kappa = 0.216). The indirect ELISA demonstrated substantial agreement with RIPA (Kappa = 0.652), with ∼76% sensitivity and ∼94% specificity for MG diagnostic. The CBA, where fixed cells expressing clustered AChR were used as substrate, exhibited almost perfect agreement with RIPA (Kappa = 0.984), yielding ∼98% sensitivity and 96% specificity for MG. In addition, a semiquantitative analysis showed a strong correlation between CBA titration, indirect ELISA, and RIPA levels (r = 0.793 and r = 0.789, respectively). Conclusions: The CBA displayed excellent analytical performance for MG diagnostic when compared to RIPA, making it a potential replacement for RIPA in clinical laboratories. Some solid-phase assays (such as the indirect ELISA applied here), as well as CBA titration, offer reliable options to estimate anti-AChR AAb levels after confirming positivity by the CBA.∥.


Asunto(s)
Autoanticuerpos , Ensayo de Inmunoadsorción Enzimática , Miastenia Gravis , Ensayo de Radioinmunoprecipitación , Humanos , Ensayo de Inmunoadsorción Enzimática/métodos , Miastenia Gravis/inmunología , Miastenia Gravis/diagnóstico , Sensibilidad y Especificidad , Receptores Colinérgicos/inmunología , Femenino , Masculino , Persona de Mediana Edad , Adulto , Anciano , Adulto Joven
7.
Sci Adv ; 10(17): eadn3760, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38669336

RESUMEN

Acetylcholine is produced in the spleen in response to vagus nerve activation; however, the effects on antibody production have been largely unexplored. Here, we use a chronic vagus nerve stimulation (VNS) mouse model to study the effect of VNS on T-dependent B cell responses. We observed lower titers of high-affinity IgG and fewer antigen-specific germinal center (GC) B cells. GC B cells from chronic VNS mice exhibited altered mRNA and protein expression suggesting increased apoptosis and impaired plasma cell differentiation. Follicular dendritic cell (FDC) cluster dispersal and altered gene expression suggested poor function. The absence of acetylcholine-producing CD4+ T cells diminished these alterations. In vitro studies revealed that α7 and α9 nicotinic acetylcholine receptors (nAChRs) directly regulated B cell production of TNF, a cytokine crucial to FDC clustering. α4 nAChR inhibited coligation of CD19 to the B cell receptor, presumably decreasing B cell survival. Thus, VNS-induced GC impairment can be attributed to distinct effects of nAChRs on B cells.


Asunto(s)
Linfocitos B , Centro Germinal , Receptores Nicotínicos , Estimulación del Nervio Vago , Receptor Nicotínico de Acetilcolina alfa 7 , Animales , Centro Germinal/metabolismo , Centro Germinal/inmunología , Estimulación del Nervio Vago/métodos , Linfocitos B/metabolismo , Linfocitos B/inmunología , Ratones , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/genética , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/genética , Células Dendríticas Foliculares/metabolismo , Células Dendríticas Foliculares/inmunología , Receptores Colinérgicos/metabolismo , Receptores Colinérgicos/inmunología , Receptores de Antígenos de Linfocitos B/metabolismo , Diferenciación Celular , Ratones Endogámicos C57BL , Inmunoglobulina G/inmunología , Nervio Vago/metabolismo , Nervio Vago/fisiología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/inmunología
8.
Schizophr Res ; 267: 8-13, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38508027

RESUMEN

Previous studies have demonstrated that the levels of IgG against neurotransmitter receptors are increased in patients with schizophrenia. Genome-wide association (GWA) studies of schizophrenia confirmed that 108 loci harbouring over 300 genes were associated with schizophrenia. Although the functional implications of genetic variants are unclear, theoretical functional alterations of these genes could be replicated by the presence of autoantibodies. This study examined the levels of plasma IgG antibodies against four neurotransmitter receptors, CHRM4, GRM3, CHRNA4 and CHRNA5, using an in-house ELISA in 247 patients with schizophrenia and 344 non-psychiatric controls. Four peptides were designed based on in silico analysis with computational prediction of HLA-DRB1 restricted and B-cell epitopes. The relationship between plasma IgG levels and psychiatric symptoms, as defined by the Operational Criteria Checklist for Psychotic Illness and Affective Illness (OPCRIT), were examined. The results showed that the levels of plasma IgG against peptides derived from CHRM4 and CHRNA4 were significantly increased in patients with schizophrenia compared with control subjects, but there was no significant association of plasma IgG levels with any symptom domain or any specific symptoms. These preliminary results suggest that CHRM4 and CHRNA4 may be novel targets for autoantibody responses in schizophrenia, although the pathogenic relationship between increased serum autoantibody levels and schizophrenia symptoms remains unclear.


Asunto(s)
Autoanticuerpos , Inmunoglobulina G , Receptores Colinérgicos , Esquizofrenia , Humanos , Esquizofrenia/sangre , Esquizofrenia/inmunología , Autoanticuerpos/sangre , Femenino , Masculino , Adulto , Persona de Mediana Edad , Inmunoglobulina G/sangre , Receptores Colinérgicos/inmunología , Ensayo de Inmunoadsorción Enzimática
9.
Rinsho Shinkeigaku ; 64(4): 292-295, 2024 Apr 24.
Artículo en Japonés | MEDLINE | ID: mdl-38508730

RESUMEN

A 79-year-old woman who presented ptosis and dysphagia were admitted to our hospital. Anti-acetylcholine receptor antibodies and anti-P/Q-type VGCC antibodies were both positive. Electrophysiological examination showed postsynaptic pattern which supported myasthenia gravis. She did not meet the diagnostic criteria for Lambert-Eaton myasthenic syndrome (LEMS). In cases which these antibodies coexist, careful electrophysiological evaluation is required for the diagnosis. In addition, although anti-P/Q-type VGCC antibodies have been specific to LEMS, patients with these antibodies represent various symptoms other than LEMS. Low and middle titer of the antibodies may be not specific to LEMS.


Asunto(s)
Autoanticuerpos , Miastenia Gravis , Receptores Colinérgicos , Humanos , Femenino , Miastenia Gravis/inmunología , Miastenia Gravis/diagnóstico , Miastenia Gravis/complicaciones , Anciano , Autoanticuerpos/sangre , Receptores Colinérgicos/inmunología , Canales de Calcio Tipo Q/inmunología , Canales de Calcio Tipo P/inmunología , Síndrome Miasténico de Lambert-Eaton/inmunología , Síndrome Miasténico de Lambert-Eaton/diagnóstico , Síndrome Miasténico de Lambert-Eaton/complicaciones
10.
Neurol Sci ; 44(10): 3707-3709, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37306795

RESUMEN

INTRODUCTION: Myasthenia gravis is a long-lasting autoimmune neuromuscular disease caused by antibodies attacking the neuromuscular junction, which can result in muscle weakness, fatigue, and respiratory failure in severe cases. Myasthenic crisis is a life-threatening event that requires hospitalization and treatments with intravenous immunoglobulin or plasma exchange. We reported the case of an AChR-Ab-positive myasthenia gravis patient with refractory myasthenic crisis, in which starting eculizumab as rescue therapy led to a complete resolution of the acute neuromuscular condition. CASE PRESENTATION: A 74-year-old man diagnosed with myasthenia gravis. ACh-receptor antibodies positivity comes to our observation for a recrudescence of symptoms, unresponsive to conventional rescue therapies. Due to the clinical worsening over the following weeks, the patient was admitted to intensive care unit, where he underwent therapy with eculizumab. About 5 days after the treatment, there was a significant and complete recovery of clinical condition with weaning-off from invasive ventilation and discharge to outpatient regimen, with reduction of steroid intake and biweekly maintenance with eculizumab. DISCUSSION: Eculizumab, a humanized monoclonal antibody that inhibits complement activation, is now approved as treatment for refractory generalized myasthenia gravis with anti-AChR antibodies. The use of eculizumab in myasthenic crisis is still investigational, but this case report suggests that it may be a promising treatment option for patients with severe clinical condition. Ongoing clinical trials will be needed to further evaluate the safety and efficacy of eculizumab in myasthenic crisis.


Asunto(s)
Anticuerpos Monoclonales Humanizados , Inactivadores del Complemento , Miastenia Gravis , Receptores Colinérgicos , Humanos , Masculino , Anciano , Miastenia Gravis/inmunología , Miastenia Gravis/terapia , Anticuerpos Monoclonales Humanizados/uso terapéutico , Inactivadores del Complemento/uso terapéutico , Receptores Colinérgicos/inmunología , Autoanticuerpos/sangre
11.
J Clin Neuromuscul Dis ; 24(4): 222-228, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37219866

RESUMEN

OBJECTIVES: To evaluate patient attitudes and beliefs toward thymectomy for myasthenia gravis (MG). METHODS: The Myasthenia Gravis Foundation of America administered a questionnaire to the MG Patient Registry, an ongoing longitudinal survey of adult MG patients. Questions assessed reasons for or against thymectomy and how hypothetical scenarios would have affected their decision. RESULTS: Of 621 respondents, 190 (31%) reported a history of thymectomy. Of those who underwent thymectomy for nonthymomatous MG, 97 (51.6%) ranked symptom improvement as most important and 100 (53.2%) ranked reducing medication as least important. Among 431 nonthymectomy patients, the most frequent reason for not undergoing thymectomy was that their doctor did not discuss it (152 of 431 = 35.2%) and 235 (56.8%) said that they would have considered it more strongly if their doctor spent more time discussing it. CONCLUSIONS: Thymectomies are motivated more by symptoms than by medication, and a lack of neurologist discussion is the most common barrier to thymectomy.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Miastenia Gravis , Pacientes , Sistema de Registros , Encuestas y Cuestionarios , Timectomía , Datos de Salud Recolectados Rutinariamente , Miastenia Gravis/epidemiología , Miastenia Gravis/cirugía , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Timoma/epidemiología , Objetivos , Receptores Colinérgicos/inmunología , Autoanticuerpos/análisis
12.
Eur J Neurol ; 30(5): 1409-1416, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36752022

RESUMEN

BACKGROUND AND PURPOSE: Complement component 5 (C5) targeting therapies are clinically beneficial in patients with acetylcholine receptor antibody+ (AChR-Ab+ ) generalized myasthenia gravis (MG). That clearly implicates antibody-mediated complement activation in MG pathogenesis. Here, classical and alternative complement pathways were profiled in patients from different MG subgroups. METHODS: In a case-control study, concentrations of C3a, C5a and sC5b9 were simultaneously quantified, indicating general activation of the complement system, whether via the classical and lectin pathways (C4a) or the alternative pathway (factors Ba and Bb) in MG patients with AChR or muscle-specific kinase antibodies (MuSK-Abs) or seronegative MG compared to healthy donors. RESULTS: Treatment-naïve patients with AChR-Ab+ MG showed substantially increased plasma levels of cleaved complement components, indicating activation of the classical and alternative as well as the terminal complement pathways. These increases were still present in a validation cohort of AChR-Ab+ patients under standard immunosuppressive therapies; notably, they were not evident in patients with MuSK-Abs or seronegative MG. Neither clinical severity parameters (at the time of sampling or 1 year later) nor anti-AChR titres correlated significantly with activated complement levels. CONCLUSIONS: Markers indicative of complement activation are prominently increased in patients with AChR-Ab MG despite standard immunosuppressive therapies. Complement inhibition proximal to C5 cleavage should be explored for its potential therapeutic benefits in AChR-Ab+ MG.


Asunto(s)
Autoanticuerpos , Activación de Complemento , Miastenia Gravis , Receptores Colinérgicos , Humanos , Autoanticuerpos/inmunología , Estudios de Casos y Controles , Activación de Complemento/inmunología , Proteínas del Sistema Complemento/análisis , Proteínas del Sistema Complemento/inmunología , Miastenia Gravis/clasificación , Miastenia Gravis/tratamiento farmacológico , Miastenia Gravis/inmunología , Receptores Colinérgicos/inmunología , Vía Alternativa del Complemento , Vía Clásica del Complemento , Masculino , Femenino , Adulto Joven , Adulto , Persona de Mediana Edad
13.
Immunol Lett ; 250: 29-40, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36108773

RESUMEN

Myasthenia gravis (MG) is characterized by fatigable skeletal muscle weakness with a fluctuating and unpredictable disease course and is caused by circulating autoantibodies and pathological T helper cells. Regulation of B-cell function and the T-cell network may be a potential therapeutic strategy for MG. MicroRNAs (miRNAs) have emerged as potential biomarkers in immune disorders due to their critical roles in various immune cells and multiple inflammatory diseases. Aberrant miR-146a signal activation has been reported in autoimmune diseases, but a detailed exploration of the relationship between miR-146a and MG is still necessary. Using an experimental autoimmune myasthenia gravis (EAMG) rat model, we observed that miR-146a was highly expressed in the spleen but expressed at low levels in the thymus and lymph nodes in EAMG rats. Additionally, miR-146a expression in T and B cells was also quite different. EAMG-specific Th17 and Treg cells had lower miR-146a levels, while EAMG-specific B cells had higher miR-146a levels, indicating that targeted intervention against miR-146a might have diametrically opposite effects. Metformin, a drug that was recently demonstrated to alleviate EAMG, may rescue the functions of both Th17 cells and B cells by reversing the expression of miR-146a. We also investigated the downstream target genes of miR-146a in both T and B cells using bioinformatics screening and qPCR. Taken together, our study identifies a complex role of miR-146a in the EAMG rat model, suggesting that more caution should be paid in targeting miR-146a for the treatment of MG.


Asunto(s)
Metformina , MicroARNs , Miastenia Gravis Autoinmune Experimental , Receptores Colinérgicos/inmunología , Animales , Autoanticuerpos , Linfocitos B , Biomarcadores , Metformina/farmacología , Metformina/uso terapéutico , MicroARNs/genética , Miastenia Gravis Autoinmune Experimental/tratamiento farmacológico , Miastenia Gravis Autoinmune Experimental/genética , Ratas , Células Th17
14.
Clin Chim Acta ; 533: 122-130, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35750085

RESUMEN

OBJECTIVE: This study aims to establish an optimization procedure to define the cut-offs of quantitative assays for acetylcholine receptor antibody (AChRAb), evaluate their diagnostic performance in myasthenia gravis (MG), and explore the association with clinical features. METHODS: Samples from a representative cohort of 77 MG patients, 80 healthy controls (HC) and 80 other autoimmune diseases (OAD) patients were tested using competitive inhibition ELISA and RIA. Raw values (OD and cpm) and processed values (inhibition rate, binding rate and concentration) were used to define the cut-offs with statistical methods, a rough method, and receiver operating characteristic (ROC) curve. Optimal cut-offs were selected by comparing false positive rates in HC and OAD individuals. The diagnostic performance was evaluated in whole MG cohort and subgroups. Agreement between ELISA and RIA for AChRAb positivity were examined with Kappa test and McNemar test. Clinical association with AChRAb was explored by comparison among subgroups and with Spearman rank correlation. RESULTS: The optimal cut-offs for AChRAb positivity were determined as OD ≤ 1.79 for ELISA and cpm ≥ 1234.12 for RIA, which derived from statistical method and performed better than those derived from ROC curves. The sensitivity and specificity were 74.03%, 100% for ELISA, and 74.03%, 99.37% for RIA. There was good agreement between ELISA and RIA for AChRAb positivity in whole cohort and subgroups (weighted к ≥ 0.71, p < 0.01; McNemar test, p > 0.05). Levels of AChRAb were different in MG subgroups (p < 0.01). Correlation between Quantitative Myasthenia Gravis scores and AChRAb levels was moderate for ELISA and RIA (rs = -0.60 and 0.57, p < 0.01). CONCLUSION: The raw testing values of ELISA and RIA were found as optimal quantitative measures of AChRAb levels. There are good agreements on diagnostic performance between two assays. Quantitative values are more informative than positivity in association with clinical features.


Asunto(s)
Miastenia Gravis , Receptores Colinérgicos , Autoanticuerpos , Ensayo de Inmunoadsorción Enzimática , Humanos , Pruebas Inmunológicas , Miastenia Gravis/diagnóstico , Receptores Colinérgicos/inmunología
15.
Ideggyogy Sz ; 75(3-04): 141-144, 2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35357789

RESUMEN

Myasthenia gravis (MG) is an autoimmune disease that is characterised by the formation of antibodies against acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction. The course of the disease cannot be predicted during pregnancy. A subtype of MG with positive muscle-specific receptor tyrosine kinase (anti-MuSK) antibodies exhibits more localised clinical characteristics and a poor response to treatment compared with the disease subtype that involves positivity for acetylcholine receptor antibodies. Myasthenic crisis is more frequently observed in anti-MuSK-positive myasthenia patients. Anti-MuSK-positive myasthenic crisis management is very difficult and a risky situation during pregnancy. The reported case was 30 years old, female, 9 weeks pregnant and musk antibody positive. She stopped her treatment without asking her doctor because she was planning pregnancy in the 6-month period before her hospitalization. She was intubated for a long time in the intensive care unit due to myasthenic crisis and was very resistant to treatment. During this period, her pregnancy was terminated due to fetal anomaly. Plasmapheresis, IVIg and immunosuppressive treatments were applied. Our patient was discharged after a period of about 10 weeks. We share our treatment management.


Asunto(s)
Autoanticuerpos , Miastenia Gravis , Proteínas Tirosina Quinasas Receptoras , Receptores Colinérgicos , Adulto , Femenino , Humanos , Miastenia Gravis/terapia , Embarazo , Proteínas Tirosina Quinasas Receptoras/inmunología , Receptores Colinérgicos/inmunología
16.
J Neuroimmunol ; 363: 577805, 2022 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-34995917

RESUMEN

Autoimmune Autonomic Ganglionopathy (AAG) is a disorder that causes autonomic failure and is associated with alpha3-ganglionic acetylcholine-receptor (gnACHR) antibodies. Assays that detect antibodies to whole gnACHR or subunits are available. We compared in-house subunit-specific immunoassays using bacterially-expressed alpha3 and beta4 subunits against an immunomodulation assay to detect antibodies in patients with AAG or control groups in a novel 2-step clinical-characteristic unblinding protocol. Only 1/8 patients with seropositive-AAG had subunit-specific antibodies, with sensitivity, specificity, false-negative and positive rates of 12.5, 85.2, 78.6 and 13.4% respectively. Subunit-specific antibody-derived false-positive results can lead to misdiagnosis, as autonomic failure is not specific to AAG.


Asunto(s)
Autoanticuerpos/análisis , Enfermedades Autoinmunes del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso Autónomo/diagnóstico , Inmunoensayo/métodos , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Enfermedades del Sistema Nervioso Autónomo/inmunología , Humanos , Receptores Colinérgicos/inmunología , Sensibilidad y Especificidad
17.
Neurol Sci ; 43(4): 2785-2790, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34709479

RESUMEN

OBJECTIVE: Myasthenia gravis (MG) is an autoimmune disorder whose main symptoms are muscle weakness and fatigue. Irisin is a novel skeletal muscle-derived myokine participating in several physiological and pathological processes. The initial objective of the project was to explore serum levels of irisin in patients with MG, as well as its correlation with disease severity. METHODS: We retrospectively evaluated serum levels of irisin in 77 MG patients and 57 healthy controls (HCs) by enzyme-linked immunosorbent assay. Further, clinical parameters were measured properly. RESULTS: Serum irisin levels were significantly elevated in MG patients compared with HCs (p < 0.001). Furthermore, serum irisin levels were associated with the myasthenia gravis activities of daily living score in ocular myasthenia gravis (OMG) patients (r = 0.476, p = 0.004), but there was no relationship to be considered of any relevant value in generalized myasthenia gravis (GMG) patients. Acetylcholine receptor antibody-positive MG patients had higher serum irisin levels compared with HCs. Thymoma, endotracheal intubation, or intensive care unit treatments subsequently were not found to have effect on serum levels of irisin, but tendencies of increase were observed in negative ones. CONCLUSIONS: Serum irisin levels were elevated in patients with MG, suggesting its possible involvement in MG. And irisin is expected to be a signal to evaluate the activities of daily living of OMG patients, while its effect needs further study.


Asunto(s)
Actividades Cotidianas , Fibronectinas , Miastenia Gravis , Autoanticuerpos/sangre , Fibronectinas/sangre , Humanos , Miastenia Gravis/sangre , Miastenia Gravis/diagnóstico , Receptores Colinérgicos/inmunología , Estudios Retrospectivos
18.
J Neurol Sci ; 432: 120084, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34906880

RESUMEN

OBJECTIVE: To compare specificity and sensitivity of a commercially available fixed cell-based assay (F-CBA) to radioimmunoprecipitation assay (RIPA) for acetylcholine receptor antibody (anti-AChR) detection in myasthenia gravis (MG). METHODS: In this retrospective diagnostic cohort study we reviewed the clinical information of suspected MG patients evaluated at the London Health Sciences Centre MG clinic who had anti-AChR RIPA and then F-CBA performed, in order to classify them as MG or non-MG. Classification of each patient as anti-AChR F-CBA-negative/positive, RIPA-negative/positive, and MG/non-MG permitted specificity and sensitivity calculations for each assay. RESULTS: Six-hundred-eighteen patients were included in study analysis. The median patient age at time of sample collection was 45.8 years (range: 7.5-87.5 years) and 312/618 (50.5%) were female. Of 618 patients, 395 (63.9%) were classified as MG. Specificity of both F-CBA and RIPA was excellent (99.6% vs. 100%, P > 0.99). One F-CBA-positive patient was classified as non-MG, although in retrospect ocular MG with functional overlay was challenging to exclude. Sensitivity of F-CBA was significantly higher than RIPA (76.7% vs. 72.7%, P = 0.002). Overall, 20/97 (21%) otherwise seronegative MG (SNMG) patients after RIPA evaluation had anti-AChR detected by F-CBA. CONCLUSIONS: In our study anti-AChR F-CBA and RIPA both had excellent specificity, while F-CBA had 4% higher sensitivity for MG and detected anti-AChR in 21% of SNMG patients. Our findings indicate that F-CBA is a viable alternative to RIPA for anti-AChR detection. Prospective studies comparing F-CBA, RIPA and L-CBA are needed to determine optimal anti-AChR testing algorithms in MG.


Asunto(s)
Autoanticuerpos/análisis , Miastenia Gravis , Receptores Colinérgicos , Femenino , Humanos , Miastenia Gravis/diagnóstico , Ensayo de Radioinmunoprecipitación , Receptores Colinérgicos/inmunología , Estudios Retrospectivos
19.
Scand J Immunol ; 95(2): e13122, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34796975

RESUMEN

Immunoadsorption apheresis (IA) or intravenous immunoglobulin (IVIg) is used to treat exacerbation of myasthenia gravis (MG). This study aimed to compare the efficacy and safety between IA and IVIg for MG patients with anti-acetylcholine receptor (AChR) antibodies. We retrospectively studied 19 AChR antibody-positive generalized MG patients who underwent IA (n = 9) or IVIg treatment (n = 10). We reviewed the MG activities of daily living profile (MG-ADL) scores at baseline, 1 and 3 months after the treatment. Adverse events during the treatment period were also reviewed. The MG-ADL scores showed significantly greater improvement from the baseline in the IA group than in the IVIg group (1 month: -7 vs -3, P = .035; 3 months -9 vs -2.5, P = .016). An adverse event that led to the discontinuation of the treatment was observed in only one patient in the IVIg group (anaphylactic reaction). Our data suggest that the IA treatment is safe and more efficacious than the IVIg treatment for aggravation of anti-AChR-positive MG. Larger prospective studies are required to confirm the finding.


Asunto(s)
Autoanticuerpos/sangre , Eliminación de Componentes Sanguíneos/métodos , Inmunoglobulinas Intravenosas/uso terapéutico , Miastenia Gravis/terapia , Autoanticuerpos/inmunología , Eliminación de Componentes Sanguíneos/efectos adversos , Femenino , Humanos , Inmunoglobulinas Intravenosas/efectos adversos , Masculino , Persona de Mediana Edad , Miastenia Gravis/inmunología , Receptores Colinérgicos/inmunología , Estudios Retrospectivos
20.
Medicine (Baltimore) ; 100(44): e27688, 2021 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-34871253

RESUMEN

ABSTRACT: Ocular myasthenia gravis (MG) is the mainly widespread type of MG among juveniles. Buzhong Yiqi decoction (BZ) is a well-known traditional Chinese medicine prescription for treating MG. It has rarely been discussed whether the concentration of anti-acetylcholine receptor (AChR) antibodies is related to the clinical status of juvenile ocular myasthenia gravis (JOMG) treated with BZ.The patients with JOMG who had more than once AChR-antibody (ab) test and treated with BZ were retrospectively identified from June 2013 to January 2020 in the first hospital in Shijiazhuang. The presence or absence of ocular symptoms was used to grade the effectiveness of treatment. Generalized estimating equations logistic regression analysis was used to evaluate the effect of AChR ab concentration on the clinical status of MG.A total of 549 AChR-ab tests were performed in 135 patients, and the corresponding clinical status was recorded. One hundred two patients received treatment with BZ only and 33 combined with immunosuppressive drugs. In the group receiving only BZ treatment, the anti-acetylcholine receptor ab concentration was positively correlated with the clinical score after treatment.The results suggest that BZ could affect the AChR-ab. Repeated AChR-ab assays can provide information about the clinical status. For JOMG patients who only receive Buzhong Yiqi Decoction treatment, this can support treatment decisions.


Asunto(s)
Autoanticuerpos/sangre , Medicamentos Herbarios Chinos/uso terapéutico , Inmunosupresores/uso terapéutico , Medicina Tradicional China/métodos , Miastenia Gravis/tratamiento farmacológico , Receptores Colinérgicos/sangre , Biomarcadores/sangre , Preescolar , Femenino , Humanos , Masculino , Miastenia Gravis/sangre , Miastenia Gravis/inmunología , Receptores Colinérgicos/inmunología , Estudios Retrospectivos , Resultado del Tratamiento
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