重症肌无力病人乙酰胆碱受体抗体的测定及临床意义

用ＥＬＩＳＡ（固相酶联免疫吸附）法测定１７２例ＭＧ病人血清乙酰胆碱受体抗体（ＡｃｈＲａｂ），结果显著高于健康献血员组和非ＭＧ病人组。不同性别、病程及临床类型与ＡｃｈＲａｂ无相关性，但４１～５０岁组的显著高于其他年龄组。６７例类固醇激素治疗组、２２例大剂量两种球蛋白治疗组、１２例胸腺切除术组及３例ＭＧ危象病人２４次血浆交换疗法（ＰＥ）组，治疗后伴随肌无力症状的好转，ＡｃｈＲａｂ均显著低于治疗前。结果表明：ＡｃｈＲａｂ测定为ＭＧ诊断提供了可靠的实验依据，为类固醇激素、大剂量丙种球蛋白、胸腺切除术和ＰＥ等治疗ＭＧ提供理论依据和疗效评定的实验指标，进一步证实了ＭＧ免疫学发病机理。     

重症肌无力患者血清IgG-乙酰胆硷受体抗体亚型研究

目的 探讨重症肌无力（ＭＧ）患者血清ＩｇＧ－乙酰胆硷受体抗体（ＡＣｈＲＡｂ）亚型的分布规律及其临床意义。方法 采用ＡＢＣ－ＥＬＩＳＡ法检测４３例ＭＧ组和２５例临床对照组、２０例正常对照组血清中ＩｇＧ－ＡＣｈＲＡｂ亚型ＩｇＧ１－４。结果 ＭＧ组与两对照组相比ＩｇＧ１和ＩｇＧ４亚型抗体无显著差别,ＩｇＧ２亚型抗体显著升高（Ｐ〈０．０５）,ＩｇＧ３亚型抗体显著降低（Ｐ〈０．０５）;ＭＧ组各临床类型间各亚型抗体无显著差别。结论 ＩｇＧ－ＡＣｈＲＡｂ亚型以ＩｇＧ２活性为主,但未显示与ＭＧ临床类型有关。     

重症肌无力患者血清白细胞介素—6水平测定

目的探讨重症肌无力(MG)与白细胞介素-6(IL-6)的关系.方法采用双抗体夹心ELISA法对30例MG患者用糖皮质激素(GC)治疗前、治疗2个月后和22例正常对照血清IL-6、乙酰胆碱受体抗体(AchRab)水平进行检测.结果MG患者组血清IL-6水平显著高于对照组(P＜0.01),MG患者组血清IL-6水平在用GC治疗2个月后显著降低(P＜0.01),其血清IL-6与血清AchRab水平呈正相关(r=0.693,P＜0.01).结论IL-6与MG发病密切相关,IL-6参加了MG的免疫病理过程;检测血清IL-6水平对MG临床有重要价值;GC可抑制IL-6合成及AchRab产生.     

葡萄球菌蛋白A免疫吸附治疗全身型重症肌无力的临床研究

目的研究葡萄球菌蛋白A免疫吸附治疗全身型重症肌无力(myasthenia gravis,MG)的疗效和安全性。方法采用蛋白A免疫吸附治疗19例成人全身型MG并进行临床疗效和安全性的判定。结果所有入选病人均完成2次免疫吸附治疗;第2次治疗后的IgG、IgA、IgM浓度明显下降(P<0.0001);Osserman分级、改良美国MG基金会(MGFA)评分、MG日常生活量表(ADL)和徒手肌力量表(MMT)均明显改善(P<0.0001)。MG特异性乙酰胆碱受体(AChR)抗体阳性的患者2次治疗后抗体滴度明显下降;治疗后外周血调节性T细胞百分比明显上升。部分病人有轻度不良反应,但总体耐受性良好,各项安全性临床评定指标在治疗前后的变化均无统计学意义。结论葡萄球菌蛋白A免疫吸附可以迅速改善全身型MG病人的病情。     

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.     

Neonatal myasthenia gravis: Clinical and immunological study of seven mothers and their newborn infants

We studied 7 mothers with myasthenia gravis (MG) and their infants. We confirmed that the development of neonatal MG was not related to the serum titer of maternal anti-acetylcholine receptor antibody (anti-AChR ab). To investigate the possibility that specific immunization of the newborn infant had occurred, serial serum determinations of total and 'specific' anti-AChR IgG and IgM were performed. We found that: the decay in total IgG was within the normal range in all the babies; there was a shorter half-life of 'specific' IgG, compared to total IgG, in 3 of the cases, 2 of which did have neonatal MG; no difference was found between the decay of anti-AChR ab in the babies who had neonatal MG and those who did not; there was no anti-AChR IgM-associated activity. Our data suggest that neonatal MG is due to maternal anti-AChR abs and that affected infants do not produce specific antibodies.     

Inhibition of peripheral blood natural killer cell cytotoxicity in patients with myasthenia gravis treated with plasmapheresis

Background and purpose: Myasthenia gravis (MG) is an autoimmune disorder that may involve natural killer (NK) cells. Although NK cells are part of the innate immune system, they also influence adaptive immune responses. Double‐filtration plasmapheresis (DFP) is an effective therapy for MG crisis. Thus, we examined the effects of DFP on the cytotoxicity of NK cells. Methods: A total of 20 patients with MG and 16 healthy controls were recruited for the study. Ficoll‐Paque‐isolated peripheral blood mononuclear cells (PBMCs) and K562 cells were used as the effector and target cells, respectively. NK cell cytotoxicity was analyzed using flow cytometry immediately before and after DFP and upon course completion. Results: Double‐filtration plasmapheresis treatment decreased significantly the NK cell cytotoxicity in patients with MG, especially in good responders, those who were positive for acetylcholine receptor (AChR) antibodies, and those receiving immunosuppressants. Conclusions: The decrease in NK cell cytotoxicity after DFP and the decline of AChR antibody titer were observed in good responders indicating that this could benefit patients with MG.     

重症肌无力病人胸腺切除术后血清自身抗体水平变化和临床转归分析

６９例重症肌无力（ＭＧ）病人行胸腺切除术，术前血清乙酰胆碱受体抗体水平均高于正常，术后半年抗体水平明显下降，胸腺增生组（２０例）尤为显著．胸腺瘤组（４９例）术前胸腺瘤相关抗体水平增高，但术后半年内无明显变化．６９例ＭＧ患者胸腺切除术后４年，症状总缓解率为７６．８１％，其中胸腺增生组９５％，胸腺瘤组６９．３９％。作者认为，对于伴有胸腺增生或胸腺瘤的ＭＧ患者，胸腺切除术是有效的，应该列为治疗的第一选择。     

Passive transfer of experimental autoimmune myasthenia gravis by monoclonal antibodies to the main immunogenic region of the acetylcholine receptor

Experimental autoimmune myasthenia gravis (EAMG) was passively transferred to rats by injecting monoclonal antibodies (mAbs) directed at the main immunogenic region (MIR) of the nicotinic acetylcholine receptor (AChR). The MIR is located on the extracellular part of the AChR alpha-subunit. All four mAbs directed at the MIR which were tested were very efficient in inducing EAMG: within 2 days the rats became moribund or very weak and their muscle AChR content decreased to about 50% of normal. These mAbs are of two different IgG subclasses (IgG1 and IgG2a) and derived from rats immunized with AChR from either fish electric organs or mammalian muscles. One mAb directed at the extracellular side of the beta-subunit did not cause AChR loss or induce symptoms of EAMG. mAbs to the cytoplasmic side were, as expected, ineffective.     

Double filtration plasmapheresis benefits myasthenia gravis patients through an immunomodulatory action

Double filtration plasmapheresis (DFPP) is used to treat myasthenia gravis (MG). However, the definite mechanism is unclear. This study investigated whether DFPP improves MG through an immunomodulatory action. Thirty-five MG patients were randomly divided into two treatment groups: Group A (DFPP combined with oral methylprednisolone) and Group B (oral methylprednisolone alone). Their antibody levels, clinical scores, cytokine levels, and CD4⁺CD25^highFoxp3⁺ (regulatory T cell [Treg]) levels were then determined. Anti-titin antibody levels were significantly lower in Group A compared with Group B after treatment. The clinical remission rate in Group A was significantly higher than in Group B. The changes in cytokine levels (interleukin [IL]-2, IL-4, IL-10, and interferon-γ) in sera and the peripheral blood mononuclear cell culture supernatants did not significantly differ before and after the treatments in both groups (p < 0.05). The soluble intercellular adhesion molecule-1 (sICAM-1) levels were lower in Group A than in Group B (p < 0.05). MG patients exhibited a lower percentage of Treg cells than normal patients. DFPP combined with methylprednisolone treatment increased the Treg cell percentage more than treatment with methylprednisolone alone (p < 0.05). DFPP treatment more effectively lowers sICAM-1 and increases Treg cell expression, consequently benefiting MG patients.     

A short plasma exchange protocol is effective in severe myasthenia gravis

Summary Plasma exchange has been reported to be a successful therapeutic procedure for the treatment of severely compromised myasthenic patients, but the optimal regimen in terms of costs or clinical benefit has not so far been determined. We have investigated the efficacy of a short plasmapheresis protocol of two exchanges 1 day apart in a series of 70 patients with severe forms of myasthenia gravis. Patients were evaluated before and 7 days after the first exchange. A positive outcome was observed in 70% of the plasma exchange cycles performed. Disease severity did not seem to be a negative prognostic factor for the efficacy of this short protocol, which was well tolerated by patients. In only 1 case were major side-effects observed. In spite of its short duration, the exchange treatment plus concomitant immunosuppressive drug therapy was not followed by early clinical deterioration.     

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.     

糖皮质激素受体阻断对大鼠实验性自身免疫性重症肌无力的影响

研究重症肌无力（ＭＧ）患者外周血白细胞糖皮质激素受体（ＧＲ）减少，而血浆皮质醇则在正常范围，探讨其与ＭＧ发病的关系。方法ＳＤ大鼠３２只，随机分成４组。实验组先以ＧＲ的竞争性拮抗剂米非司酮（ＲＵ３８４８６，ＲＵ４８６）阻断其ＧＲ，再以从人肌肉中粗提的乙酰胆碱受体（ｎＡＣｈＲ）进行免疫；实验对照组单用ｎＡＣｈＲ，试剂对照组只用ＲＵ４８６，而正常对照组仅用福氏佐剂。以临床症状、血清抗ｎＡＣｈＲ抗体（ｎＡＣｈＲ－ａｂ），重复刺激坐骨神经递减幅度为观察指标。结果实验组的临床症状和ｎＡＣｈＲ－ａｂ滴度升高及肌电图递减幅度均较明显，经ｔ检验分析，均与实验对照组有显著性差异（Ｐ＜０．０５），而试剂对照组和正常对照组均无ＭＧ的表现。结论ＧＲ被阻断后，对大鼠的实验性自身免疫性ＭＧ（ＥＡＭＧ）发病有易化作用。     

Acetylcholine-receptor-like protein from human thymoma associated with myasthenia gravis

Summary Cobrotoxin-binding protein was isolated by affinity chromatography from human thymoma which had been surgically removed from patients with myasthenia gravis. The protein was composed of polypeptides with a molecular mass of 40, 51, 65, and 74 kilodaltons as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl-sulphate. Isoelectric focusing of the protein gave pI values of 5.2–5.6 and 11. This is the first report of the isolation of the protein from human thymoma. These findings suggest that the cobrotoxin-binding protein from human thymoma patients with myasthenia gravis has subunits similar to those of fish electric organs or mammalian muscles.     

Cellular response to human acetylcholine receptor in patients with myasthenia gravis

A preparation of human skeletal muscle acetylcholine receptor (AchR) was used in vitro as an antigen to stimulate lymphocytes from patients with myasthenia gravis (MG). Clinical data obtained from the patients included duration and severity of disease; history of steroid treatment or prior thymectomy; and the presence of thymoma. Lymphocytes from patients with MG showed a significantly higher response to human AchR antigen than did lymphocytes from control subjects. Previous studies of cellular response to AchR have used receptor prepared from eel or ray electric organs. By stimulating lymphocytes from MG patients with a preparation of human AchR, we have come one step closer to documenting a possible contribution of a cellular immune response to the pathogenesis of MG.     

重症肌无力血清乙酰胆碱受体抗体的阳性率及其影响因素

采用ABC-ELISA法检测162例重症肌无力患者的224份血清标本,100例正常人和78例其他疾病病人的血清中AchRab。重症肌无力病人的抗体阳性率为80.2％,其中单纯眼肌型63.1％,脊髓肌型90.0％,延髓肌型93.8％和全身肌型91.5％。合并胸腺瘤的阳性率为83.3％,与全组阳性率无显著性差异。激素和血浆交换治疗均未影响抗体阳性结果。随访观察表明,重症肌无力病人的AchRab阳性率与疾病严重程度不成线性相关。我们认为,AchRab滴度虽然与临床状况不相关,但在重症肌无力的诊断和自身免疫病因的研究中,仍是一项重要参数。     

Effect of plasma exchange on carbamazepine levels in a patient with myasthenia gravis and epilepsy

PURPOSE: Patients taking antiepileptic medications may require plasma exchange (PEX) for treatment of an unrelated condition. METHODS: We studied total serum levels of carbamazepine (CBZ) serially, before and after five PEX cycles, in an epilepsy patient who underwent PEX for myasthenia gravis. RESULTS: A small but consistent reduction in the CBZ levels was noted immediately after each cycle, and a gradual and cumulative increase in the serum levels was observed over the duration of the PEX cycles. CONCLUSIONS: We conclude that alterations in the serum CBZ levels with PEX are not clinically significant to merit adjustment of the CBZ dose.     

重症肌无力中枢神经系统受损模型

目的近年研究结果表明，重症肌无力（ＭＧ）病变部位并不仅仅局限于神经肌接头（ＮＭＪ）处突触后膜烟碱型乙酰胆碱受体（ｎＡＣｈＲ），烟碱型乙酰胆碱受体抗体（ＡＣｈＲ－ａｂ）病理作用可能波及到中枢神经系统（ＣＮＳ）。因此，有必要建立模拟ＭＧ患者ＣＮＳ损害的动物模型，研究ＭＧ患者脑脊液中存在的ＡＣｈＲ－ａｂ引起ＣＮＳ损害的机制。方法从ＭＧ患者血中提取的ＡＣｈＲ－ａｂ经侧脑室穿刺注入到大鼠脑室系统，然后观察其症状和体征，以及用脑干听觉诱发电位仪（ＢＡＥＰ）检测鼠脑干听觉传导中枢功能。用免疫组化法（ＡＢＣ）研究ＡＣｈＲ－ａｂ与ＣＮＳ神经－ｎＡＣｈＲ之间免疫结合反应及其分布。结果大鼠除了出现脑干听觉传导中枢功能障碍外，还出现类似于ＭＧ动物模型表现的症状。免疫组化研究结果显示，神经－ｎＡＣｈＲ样阳性免疫反应广泛分布于ＣＮＳ许多部位。结论脑室内注入的ＡＣｈＲ－ａｂ与神经－ＡＣｈＲ结合引起ＣＮＳ功能障碍和出现ＭＧ动物模型样症状。我们首次建立的中枢受损的ＭＧ模型将有助于阐明ＡＣｈＲ－ａｂ引起中枢受损和ＣＮＳ下位运动神经元引起横纹肌收缩无力的机制。     

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     

Immunosuppressive treatment of rippling muscles in patients with myasthenia gravis

Rippling muscle disease is a rare autosomal dominant disorder that may occur sporadically. In this report two patients presenting with rippling muscles followed by myasthenia gravis are described. Our first patient developed rippling muscles about 1 month after infection with Yersinia enterocolitica. Two years later myasthenia gravis appeared. Our second patient had a 2-year history of asthma prior to the onset of rippling muscles which preceded the myasthenic symptoms by 4–8 weeks. Acetylcholine receptor and anti-skeletal muscle antibody titers were positive in both patients. In both patients the rippling phenomena worsened with pyridostigmine treatment but markedly improved after immunosuppression with azathioprine.