Changes in serum cytokine levels during plasmapheresis in patients with myasthenia gravis

Background: The effect of plasmapheresis on cytokine levels in patients with myasthenia gravis (MG) has not been well established. Methods: Cytokine levels were measured in 19 patients with MG before and after treatment with one course of double‐filtration plasmapheresis (DFP). The control group comprised 6 age‐ and sex‐matched healthy volunteers. Results: At baseline, patients with MG had higher levels of IL‐10 than normal controls. The levels of IL‐2, IL‐4, IL‐5, and tumor necrosis factor‐α were almost undetectable in MG patients. After a single session of DFP treatment, IL‐10 levels were significantly increased. After three sessions, IL‐10 levels were still higher than those at baseline. Elevated IL‐10 level was significantly associated with use of immunosuppressant drugs, thymectomy, and good response to DFP treatment. Conclusions: Interleukin‐10 might play a crucial role in the pathogenesis and perpetuation of MG.     

Acetylcholine receptor antibody in myasthenia gravis

Radioimmunoassay techniques were used to detect antibodies to the acetylcholine receptor (AAChR) in 164 patients with adult-onset myasthenia gravis. AAChR levels above 0.6 nM/l were considered pathological and were found in 67% of the patients with an average value of 58.99 +/- 125.02 nM/l (0.6-900.0). Correlation, with clinical functional status, the histopathological thymus alterations and the different therapeutics used did not disclose any statistically significant differences.     

Comparison between double-filtration plasmapheresis and immunoadsorption plasmapheresis in the treatment of patients with myasthenia gravis

Two techniques for plasmapheresis are used in the treatment of myasthenia gravis (MG): immunoadsorption (IA) and double filtration (DR). This controlled study evaluated the differences between these techniques in clinical effects and serological changes. Five patients with generalized MG (clinical states IIb and III) were enrolled; each patient received IA and DF plasmapheresis on separate occasions. Immunosorba TR-350 with an affinity to acetylcholine receptor antibodies (AchRAb) was used for IA, while Evaflux 4A was used as the plasma fractionator for DF. Each course of treatment consisted of five sessions of apheresis. MG score, titers of AchRAb, immunoglobulins (IG), and plasma biochemistry were assessed by blinded examiners before and immediately after the entire course of treatment. Both treatments effectively ameliorated symptoms of MG. There were no significant changes in MG score between the two groups (IA vs. DF: 2.2 vs. 2.6, P>0.5). IA had a higher clearance rate of AchRAb than DF (66 % vs. 54 %, P<0.05), while DF removed more IgA (72 % vs. 21 %, P< 0.05) and IgM (89 % vs. 57 %, P<0.01) than did IA. Although IA removed AchRAb more effectively than DF, the clinical effects between these two treatments were similar. The titers of AchRAb cannot reflect the clinical severity. Some circulating factors other than AchRAb may contribute to the pathogenesis of MG. Received: 10 September 1999, Received in revised form: 7 February 2000, Accepted: 24 February 2000     

Correlation of C3 level with severity of generalized myasthenia gravis

Acute exacerbation of generalized myasthenia gravis (GMG) can cause swallowing impairment, respiratory failure, or death. It is important to identify immunological factors that might be regarded reliably as an index of the patient's clinical condition, response to treatment, and measure of certain immune aberrations of MG. In this study we investigated correlations between complement component C3, acetylcholine receptor antibody (AChRab) titer, and clinical severity of GMG. AChRab titer and C3 concentration were determined by radioimmunoassay and nephelometry, respectively. The clinical severity of GMG was assessed by the quantitative MG score (QMGS) according to Besinger and colleagues. Our findings indicate that the C3 level correlates with clinical severity of AChRab‐positive GMG. Muscle Nerve, 2009     

Juvenile myasthenia gravis with prepubertal onset

Juvenile myasthenia gravis (JMG) with prepubertal onset is an uncommon disease. We studied 19 patients with age at onset ranging from 1.5 to 9.2 years and compared their clinical characteristics and response to therapy with 114 cases with MG onset after the prepubertal age, up to 20 years. Neither sex prevalence nor autoimmune diseases other than MG were found in younger patients. Although ocular myasthenia was more frequent than in later-onset JMG, children with generalized symptoms were often severely affected and respiratory involvement was present in 8/19 patients. Anti-acetylcholine receptor antibodies were detected at a lower rate and, in contrast with results in older patients, seronegativity was more frequent among children with generalized disease. Three out of six patients with onset before the age of five showed spontaneous remission. Nine prepubertal patients underwent thymectomy and, as most of them also received immunosuppressive therapy, the influence of surgery on disease outcome remains unclear; in no case was thymoma found. This is in contrast to the good results after thymectomy and the presence of thymoma in the later-onset group. Eleven patients in the prepubertal series were treated with immunosuppressive therapy. At the end of follow-up, most patients were in good condition. The frequency of immunosuppressive therapy and the rate of good therapeutic results did not differ from those observed in older patients.     

白细胞介素-6与重症肌无力患者临床特点的关系

目的　探讨白细胞介素 6(IL 6)与重症肌无力(MG)患者临床特点的关系。方法　采用双抗体 夹心ELISA法检测36例MG患者及20名健康对照者的血清IL 6和乙酰胆碱受体抗体(AchRAb)水平,并分 析其与MG临床特点的关系。结果　MG患者血清IL 6水平高于健康对照者(P<0.01);AchRAb阳性患者 高于阴性患者(P<0.05);全身型患者高于眼肌型患者(P<0.05);病情重者高于病情轻者(P<0.05);急性 期高于非急性期(P<0.01);预后差者高于预后好者(P<0.05);伴胸腺异常者高于胸腺正常者(P<0.05)。 结论　IL 6与MG临床特点相关,在MG发病机制中起重要作用。血清IL 6水平可间接反映体内免疫功能紊 乱的程度,对判断MG患者病情、预后和指导治疗有重要的参考价值。     

乙酰胆碱受体抗体阳性重症肌无力外周血单个核细胞miRNA表达谱

目的本研究对比乙酰胆碱受体抗体阳性重症肌无力患者(AchR-MG)和正常对照组外周血单个核细胞miRNA,预测对AchR-MG发病可能产生影响的通路,为进一步探讨发病机制打下基础。方法采用病例对照研究方法,基于高通量测序,筛选了AchR-MG特异性表达的miRNA。利用TargetScan、miRanda进行靶基因交叉预测,利用基因条目(GO)和京都基因与基因组百科全书(KEGG)进行富集分析。结果共筛选出差异性miRNA 28种,其中上调17种,下调11种。差异最显著的前5个为:mmu-miR-3968、miR-4785、miR-210-3p、miR-664a-3p、miR-2277-5p。miR-4785预测到METTL22、TMEM38A、ZNF324、ITGB4、CDC34等395种靶基因。最终识别了319条GO term(P 0.01),获得了119个的风险通路(P0.05)。结论 AchR-MG特异性表达miR-4785、miR-210-3p、miR-664a-3p、miR-2277-5p等28种miRNA。以Wnt信号通路为代表的多种通路可能参与AchR-MG的发病。     

Comparison of diagnosis value for new onset myasthenia gravis by many clinical auxiliary examinations

BACKGROUND: The clinical values of neostigmine test, clinical electrophysiologic study and acetylcholine receptor antibody detection in diagnosing myasthenia gravis (MG) found newly are unclear in China. OBJECTIVE: To investigate the reference value of common clinical diagnosis parameters in correctly diagnosing untreated MG found newly. DESIGN: Retrospective case analysis. SETTING: Department of Neurology, Beijing Hospital, Ministry of Health. PARTICIPANTS: Totally 156 outpatients with MG admitted to Department of Neurology, Beijing Hospital, Ministry of Health between January 1999 and December 2002. The involved patients, 72 males and 84 females, were aged 2–79 years. They were classified according to Osserman's criteria: ⅡA 72，ⅡB 76, Ⅲ 3 and Ⅳ 5. They were all subjected to being inquired of disease history, neostigmine test, and acetylcholine receptor antibody detection, met the diagnosis criteria of Neuroimmunology Committee of China, and confirmed by clinical electrophysiologic detections; Informed consents were obtained from all the involved subjects. METHODS: ①After admission, every patient was intramuscularly injected with 1.5 mg neostigmine; If the patient was a child, the injection dose was decreased according to his/her age. If his/her score of any observation index after injection was improved ≥ 50% as compared with before injection , his positive index was set as positive. Positive neostigmine test was set if there was one positive index. ②Repetitive nerve stimulation and single fiber electromyography were performed with Dantec Keypoint electromyogram (EMG) apparatus. ③Acetylcholine receptor antibody was detected by ELISA method. MAIN OUTCOME MEASURES: Clinical absolute and relative scores of MG, acetylcholine receptor antibody level, and repetitive nerve stimulation and single fiber electromyography examination results. RESULTS: The positive rates of neostigmine test, repetitive nerve stimulation and single fiber electromyography examination for MG were 86.5%, 82.6%, and 69.2%, respectively, and the positive rate of acetylcholine receptor antibody was 78.8%. CONCLUSION: Standardized neostigmine test has the highest sensitivity to diagnose MG.     

乙酰胆碱受体抗体阳性重症肌无力外周血单个核细胞miRNA表达谱

目的 本研究对比乙酰胆碱受体抗体阳性重症肌无力患者（AchR-MG）和正常对照组外周血单个核细胞miRNA,预测对AchR-MG发病可能产生影响的通路,为进一步探讨发病机制打下基础。方法 采用病例对照研究方法,基于高通量测序,筛选了AchR-MG特异性表达的miRNA。利用TargetScan、miRanda进行靶基因交叉预测,利用基因条目（GO）和京都基因与基因组百科全书（KEGG）进行富集分析。结果 共筛选出差异性miRNA 28种,其中上调17种,下调11种。差异最显著的前5个为：mmu-miR-3968、miR-4785、miR-210-3p、miR-664a-3p、miR-2277-5p。miR-4785预测到METTL22、TMEM38A、ZNF324、ITGB4、CDC34等395种靶基因。最终识别了319条GO term（P<0.01）,获得了119个的风险通路（P<0.05）。结论 AchR-MG特异性表达miR-4785、miR-210-3p、miR-664a-3p、miR-2277-5p等28种miRNA。以Wnt信号通路为代表的多种通路可能参与AchR-MG的发病。     

Clinical findings in MuSK‐antibody positive myasthenia gravis: A U.S. experience

We performed a retrospective chart review on 53 muscle‐specific kinase antibody (MuSK‐Ab)‐positive myasthenia gravis (MG) patients at nine university‐based centers in the U.S. Of these, 66% were Caucasian, 85% were women, and age of onset was 9–79 years. Twenty‐seven patients were nonresponsive to anticholinesterase therapy. Myasthenia Gravis Foundation of America improvement status was achieved in 53% patients on corticosteroids, 51% with plasma exchange, and in 20% on intravenous immunoglobulin (IVIG). Thymectomy was beneficial in 7/18 patients at 3 years. Long‐term (≥3 years) outcome was very favorable in 58% of patients who achieved remission and/or minimal manifestation status. Overall, 73% improved. There was one MG‐related death. This survey reinforces several cardinal features of MuSK‐Ab‐positive MG, including prominent bulbar involvement and anticholinesterase nonresponsiveness. Facial or tongue atrophy was rare. Most patients respond favorably to immunotherapy. The best clinical response was to corticosteroids and plasma exchange, and the poorest response was to IVIG. Long‐term outcome is favorable in about 60% of cases. Muscle Nerve, 2009     

Increased serum interleukin-17 levels in patients with myasthenia gravis

It has been suggested that interleukin-17 (IL-17) plays a crucial role in the development of several autoimmune diseases. However, there are no data about the relationship between myasthenia gravis and IL-17. The aim of this study was to measure the concentration of IL-17 and determine whether levels depend on the severity of MG. Serum IL-17 concentrations were measured in 25 patients. IL-17 concentrations were higher in generalized MG compared with controls and correlated with anti-acetylcholinesterase receptor antibody titers.     

Double filtration plasmapheresis in myasthenia gravis - analysis of clinical efficacy and prognostic parameters

OBJECTIVES: The aim of this study was to evaluate the efficacy of double filtration plasmapheresis (DFP) in the treatment of patients with myasthenia gravis (MG) and to analyze the possible prognostic factors related to responsiveness to DFP. MATERIALS AND METHODS: We treated 45 MG patients, 26 women and 19 men aged 21-72 years, with DFP for 5 consecutive sessions. All were affected by severe generalized or respiratory weakness with an Osserman's classification of group 2 or 3 and had not responded to previous treatments. RESULTS: Thirty-eight out of 45 patients (84%) achieved significant improvements after DFP. The baseline MG score and removal rate for immunoglobulin G (IgG) were significantly higher in the patients with good response than in the other response groups. Poor responders were more likely to have thymoma and a longer interval among sessions of DFP. Better response in patients with age at onset of less than 40 years was associated with higher MG score. Serum concentration of all proteins tested fell as follows (mean +/- SD): IgM, 88+/-7%; IgA, 71+/-11%; IgG, 59+/-14%; globulin, 52+/-11%; AchRAb, 47+/-14%; and albumin, 27+/-10%. All the patients tolerated plasmapheresis well except for 2.2% who experienced hypotension. CONCLUSION: In this study, DFP was effective and safe in the treatment of patients with severe generalized MG. The factors correlating with the better clinical response were high MG score, a thymic pathology of non-thymoma, daily apheresis, young age at onset, and high removal rate for IgG.     

Morphological effects of myasthenia gravis patient sera on human muscle cells

Myasthenia gravis (MG) is caused primarily by autoantibodies against the nicotinic acetylcholine receptor (AChR), but autoantibodies to other muscle proteins may be present. Many of these proteins have structural or signalling functions, the disruption of which may affect muscle cell morphology or viability. In order to investigate the role of such autoantibodies in MG, we examined the effect of MG patient sera, of different autoantibody composition and obtained at different stages of disease severity, on primary human muscle cells. Sera from MG patients induced changes in cell morphology from typical elongated cells to an irregular phenotype, caused the formation of inclusion bodies and intracellular vesicles, and led to a disordered arrangement of actin microfilaments. Sera from the most severely affected patients also induced cell death, which did not occur via classic apoptosis. The effects were not complement-mediated and were dose- and time-dependent. As the effects observed in the cell culture system correlated with disease severity, a greater understanding of the individual factors responsible for these effects may improve our understanding of MG pathogenesis and be of value in the assessment of disease in individual patients.     

眼肌型及全身型重症肌无力患者外周血T淋巴细胞Fas的表达

目的 探讨Fas介导的细胞凋亡与眼肌型(ocular myasthenia gravis,OMG)及全身型重症肌无力(generalized myasthenia gravis,GMG)发病的关系.方法 采用流式细胞技术检测4例OMG、13例GMG患者及13例健康对照组外周血淋巴细胞中CD4、CD8及Fas的表达.结果 OMG、GMG组与对照组外周血T淋巴细胞表面CD4、CD8分子表达的差异无统计学意义(P>0.05).GMG组与对照组外周血T淋巴细胞中Fas+细胞比例的差异有统计学意义(41.72%±8.73%、31.22%±13.00%,P:0.017).GMG组与对照组Fas表达增高者比例的差异有统计学意义(61.5%、15,4%,P=0.041).Fas表达增高的GMG患者病情较重.病程较长.胸腺瘤发生率较高.OMG与GMG组外周血T淋巴细胞中Fa8+、CD4+Fas+、CD8+Fas+细胞比例差异无统计学意义(P>0.05).结论 GMG患者外周血T淋巴细胞中Fas的表达升高,OMG与GMG患者外周血T淋巴细胞中Fas的表达无显著差异,二者可能同属一种系统性疾病.     

The B-cell repertoire in myasthenia gravis includes all four acetylcholine receptor subunits

By enumerating cells secreting IgG antibodies of particular specificities using an enzyme-linked immunospot (ELISPOT) assay, the B-cell responses to Torpedo acetylcholine receptor (AChR) and its α-, β-, γ- and δ-subunits in peripheral blood from patients with myasthenia gravis (MG), and controls with other neurological diseases (OND) as well as healthy subjects were determined. Compared to controls, the patients with MG had elevated numbers of B cells secreting antibodies against AChR and its α-, β-, γ- and δ-subunits in peripheral blood in parallel. The mean numbers of anti-AChR antibody secreting cells were about 17 per 10⁵ blood MNC, and for the subunits 10 to 15 in MG patients, compared to between 0.8 and 1.9 per 10⁵ blood MNC in OND patients, and 0.1 to 0.3 in healthy controls. Such B cells detected in controls probably represent naturally occurring B cells responded to AChR and its subunits. The finding that most (60%) MG patients had B cells predominantly recognizing the α-subunit may be an indirect argument for the existence of a main immunogenic region (MIR). In the remaining 40% of patients with MG the predominant B-cell responses were directed to β-, γ- or δ-subunit. The data suggest that all four AChR subunits may function as strong immunogens in MG, though the α-subunit may be the major immune target in a substantial proportion of MG patients.     

Outcome of plasmapheresis in myasthenia gravis: delayed therapy is not favorable

Introduction: The purpose of this study was to compare the in‐hospital mortality and complication rates after early and delayed initiation of plasma exchange (PLEX) in patients with myasthenia gravis (MG). Methods: Our cohort was identified from the Nationwide Inpatient Sample database for the years 2000 through 2005. Early treatment was defined as therapy with PLEX administered within the first 2 days from hospital admission. Univariate and multivariate analyses were employed. Results: One thousand fifty‐three patients were treated and included in the analysis. A delay in receiving PLEX was associated with higher mortality (6.56% vs. 1.15%, P < 0.001) and increased complications (29.51% vs. 15.29%, P < 0.001). Adjusted analysis showed increased mortality [odds ratio (OR) 2.812; 95% confidence interval (CI) 1.119–7.069] and complications (OR 1.672; 95% CI 1.118–2.501) with delayed PLEX therapy. Conclusions: Delaying PLEX therapy for MG by more than 2 days after admission may lead to higher mortality and complication rates, and thus prompt therapy is warranted. Muscle Nerve 43: 578–584, 2011     

Widely varying TNF-α levels in patients with myasthenia gravis

Animal studies have indicated an important role of tumor necrosis factor-alpha (TNF-α) in the pathogenesis of myasthenia gravis (MG), and trials of monoclonal antibodies that block TNF-α have shown clinical improvement. However, before a TNF-α blocking agent is proposed for treatment of MG, whether serum TNF-α level correlates with the patient’s condition should be confirmed. Therefore, we evaluated the relationship between the serum TNF-α level and clinical factors, including the quantitative MG score and the anti-acetylcholine receptor antibody level, in 33 MG patients. TNF-α levels ranged from 0.44 to 3.63 pg/mL and did not correlate with clinical factors. Overall, we found that serum TNF-α levels varied greatly among MG patients.     

Predictors of response to immunomodulation in patients with myasthenia gravis

Introduction: Factors determining response to intravenous immunoglobulin (IVIg) and plasmapheresis in myasthenia gravis (MG) have not been evaluated systematically. Methods: This study included patients treated with IVIg (n = 63) or plasmapheresis (n = 42) from two trials evaluating IVIg vs. placebo or plasmapheresis in MG. Response was defined as improvement in the quantitative myasthenia gravis score (QMGS) of ≥3.5 points at day 14. Baseline clinical, electrophysiological, and immunological factors were analyzed as predictors. Results: Baseline QMGS, acetylcholine receptor antibody (AChRAb) positivity, single‐fiber electromyography (SFEMG) jitter, and percent abnormal pairs and percent blocking pairs were higher in responders than in non‐responders. Using multivariate logistic regression, the odds ratio for response was 13.0 (1.01–381.5) in QMGS 11–17 and 15.3 (1.34–414.3) in QMGS >17 compared with QMGS <11. Conclusions: Baseline QMGS, AChRAb positivity, and SFEMG parameters were more abnormal in patients who responded to treatment. Using multivariate regression, baseline QMGS remained as the only significant independent predictor of response. Muscle Nerve, 2012     

Mortality in myasthenia gravis: A nationwide population–based follow‐up study in Denmark

Introduction: In previous studies of myasthenia gravis (MG), increased mortality has been reported. The aim of this study was to estimate mortality in patients with acetylcholine receptor antibody–positive (AChR‐Ab–seropositive) MG in a nationwide population–based, long‐term follow‐up study. Methods: All AChR‐Ab–seropositive MG patients, diagnosed between 1985 and 2005, were identified. Defined by age at diagnosis (≤50 or >50 years), patients were classified as having early‐ or late‐onset MG. For comparison, 10 non‐MG individuals from the general population were matched with each patient. All patients and controls were followed until January 1, 2009. Mortality rates and estimated mortality rate ratios (MRRs) were calculated. Results: Of 702 AChR‐Ab–seropositive MG patients, 302 died during follow‐up. Overall mortality was higher for patients with MG (MRR = 1.41, range 1.24–1.60). In late‐onset women and men, the MRRs were 1.64 (1.36–1.99) and 1.22 (1.02–1.46), respectively. Total MRR was highest during the first 5 years after diagnosis. Conclusions: MG diagnosis is still associated with increased mortality. Muscle Nerve 53 : 73–77, 2016