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.     

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.     

重症肌无力患者血清可溶性Fas水平变化及其临床意义

目的探讨重症肌无力(MG)患者血清可溶性Fas(sFas)水平变化及其临床意义。方法采用流式细胞术及酶联免疫吸附法(ELISA)分别测定45例MG患者(MG组)及40例对照者(对照组)外周血T细胞亚群分布和血清sFas水平,并对其中24例MG患者应用糖皮质激素(GC)治疗前后的血清sFas水平进行比较。结果(1)MG组外周血中CD8 T细胞百分率为(21.50±2.21)%,明显低于对照组[(27.75±3.00)%](P<0.01);CD4 /CD8 比值(1.92±0.26)明显高于对照组(1.48±0.16)(P<0.01);血清sFas水平[(3542.06±706.23)pg/m l]显著高于对照组[(2568.18±562.48)pg/m l](P<0.01)。(2)MG组全身型血清sFas水平为(3914.23±804.81)pg/m l,极明显高于眼肌型[(2797.72±592.83)pg/m l](P<0.001);病情中、重度患者明显高于病情轻度者(均P<0.005);预后良好者[(3254.69±661.73)pg/m l]显著低于预后不良者[(4178.38±841.65)pg/m l](P<0.001)。(3)24例MG患者经GC治疗后sFas水平[(2864.59±617.43)pg/m l]较治疗前[(3539.67±705.92)pg/m l]极显著降低(P<0.001)。结论MG患者血清凋亡抑制因素sFas水平增高,并与MG类型、病情及预后相关;GC治疗可以改善MG患者的免疫功能。     

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     

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     

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     

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.     

重症肌无力患者血清连接素抗体与临床的关系

目的 探讨重症肌无力（MG）患者血清连接素抗体（Titin—Ab）水平与病情及胸腺异常的关系,以及其对诊断和预后判断的价值。方法 应用酶联免疫吸附法（ELISA）检测MG患者（MG组）52例、非MG（其他神经系统疾病）患者（NMG组）18例、健康对照者（NC组）50名血清中Titin—Ab水平,并对其中10例进行胸腺手术的MG患者随访。结果 MG组Titin—Ab阳性率为36．5％,NMG组和NC组均为阴性,MG组显著高于NC组和NMG组（均P〈0．01）;以MG伴胸腺瘤（MGT）组阳性率最高（83．3％）,MG伴胸腺萎缩（MGA）次之（37．5％）,胸腺正常的MG组为23．0％,MG伴胸腺增生组为阴性;Titin．Ab诊断MGT特异性高于胸腺CT（P〈0．05）。Titin—Ab阳性MG患者抗体水平与肌无力程度呈显著正相关（r=0．562,P〈0．01）;对10例不同胸腺病理类型的MG患者手术前后Titin—Ab测定显示差异具有显著性（P〈0．05）。结论 Titin—Ab阳性多见于MGT和MGA者,诊断MGT的特异性高于CT;Titin—Ab对MG的诊断、病情及预后判断均有帮助。     

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.     

非胸腺瘤性眼外肌麻痹起病重症肌无力胸腺切除时机探讨

目的比较非胸腺瘤性眼外肌麻痹起病重症肌无力(ocular onset myasthenia gravis,OMG-O)患者于不同病程行胸腺切除后病情缓解与向全身型重症肌无力(GMG)转化的差异,以期对手术时机进行探讨。方法采用双向队列研究方法,对作者医院2005年1月至2017年9月因药物治疗效果不佳而行胸腺切除的86例OMG-O患者,按起病至手术时间间隔分为早手术组(≤1年)、晚手术组(>1年),比较两组患者不同随访时间理想状态(干预后状态达到轻微异常及更好)率、GMG转化率的差异。结果 (1)与早手术组比较,晚手术组少年MG(<18岁)比例较高,起病至手术时间间隔、起病至使用激素时间间隔、激素用药时间较长(均P <0.05)。(2)与晚手术组比较,早手术组术后第3年理想状态率高(P=0.029),而第2、4~8年理想状态率有升高趋势,但差异无统计学意义(P>0.05)。(3)9例术后发生GMG转化,起病至发生GMG转化时间中位数17.8个月,其中6例(66.7%)在3年内发生GMG转化。早手术组与晚手术组间GMG转化率比较,差异无统计学意义(12.5%比8.7%;χ~2=0.049,P=0.825)。结论对于药物治疗无效或不耐受的OMG-O患者,早期行胸腺切除手术疗效较好;但即使手术,仍有可能发生GMG转化,约1/2患者于起病后1.5年内发生,约2/3于起病后3年内发生。     

Tongue force in patients with myasthenia gravis

OBJECTIVES: The aim was to study tongue force in patients with bulbar myasthenia gravis and compare it with that of patients with ocular myasthenia gravis, patients in clinical remission who previously suffered from bulbar myasthenia gravis, and healthy subjects. MATERIAL AND METHODS: Tongue force was measured with a tongue force transducer in cranial and lateral directions, which coincide with the directions in which the tongue exerts force during swallowing, speech, and mastication. RESULTS: Tongue force in lateral direction was significantly decreased in patients with bulbar myasthenia gravis. In addition, our findings suggest an incomplete recovery of lateral tongue force in the patients of the remission group. CONCLUSION: Our tongue force measurements may be useful for longitudinal evaluation of therapy in individual patients and also in studies of therapy efficacy in matched groups of patients if the influence of factors such as age, dental state, and sex is taken into account.     

Thymectomy in late-onset myasthenia gravis

Two cases of late-onset myasthenia gravis were successfully treated by thymectomy using a sternal splitting technique, in spite of the fact that no thymomas could be detected preoperatively. One patient was seriously ill, the other patient responded to medical treatment. Thymolipoma and malignant thymoma, respectively, were removed from the patients. It is stressed that not all thymomas produce antibodies to striated muscles and that CT-scan of the mediastinum is of limited value in the diagnosis of thymoma. It is suggested that patients with late-onset myasthenia gravis be offered thymectomy, even in the absence of detectable thymomas.     

Thymolipoma in patients with myasthenia gravis: report of two cases and review

Two cases of simultaneous occurrence of myasthenia gravis (MG) and thymolipoma are described and 4 previously reported cases are reviewed. In all 6 cases, thymectomy was performed. Pre- and postoperatively, the clinical status of the patients was similar to that of late-onset MG without thymolipoma. It is possible that simultaneous occurrence of MG and thymolipoma may be coincidental.     

Sympathetic skin response in patients with myasthenia gravis★ A comparative analysis

BACKGROUND: The examination of sympathetic skin response is an important index for assessing the autonomic nerve function, and patients with myasthenia gravis are always accompanied by dysautonomia. Therefore, it will be important to know whether sympathetic skin response can be used as the index for the clinical evaluation of myasthenia gravis. OBJECTIVE: To investigate the diagnostic value of sympathetic skin response in the damage of autonomic nerve function of patients with myasthenia gravis. DESIGN: A case-controlled comparative observation. SETTING: Department of Neurology and Room of Nerve Electromyogram, the Affiliated Hospital of North Sichuan Medical College. PARTICIPANTS: Thirty outpatients or inpatients with myasthenia gravis were selected from the Department of Neurology, the Affiliated Hospital of North Sichuan Medical College from May 2006 to May 2007, including 9 males and 21 females, aged 8–72 years with a mean age of (28±5) years old. They were all accorded with the diagnostic standards of myasthenia gravis, accompanied by different severity of autonomic nerve symptoms, including poor skin nutrition, sweating of hands and feet, pyknocardia, persistent hypotension, abdominal pain, constipation, etc. They all had not taken any drug affecting the autonomic nerve function before the examination. Informed consents were obtained from all the patients. Meanwhile, 30 healthy physical examinees were enrolled as the normal control group, including 10 males and 20 females, aged 10–75 years with a mean age of (31±5) years old. Approval was obtained from the hospital ethic committee. METHODS: After admission, the patients were examined with sympathetic skin response using DANTEC keypoint 2.0 electromyography evoked potential apparatus (Danmark). The changes of the latency and wave amplitude of sympathetic skin response were observed. The subjects in the normal control group were examined with the same methods at physical examination. Abnormality was judged by the disappearance of wave form, latency longer than that in the normal control group by Mean±2.5SD, or wave amplitude lower than the average value in the normal control group by 50%. MAIN OUTCOME MEASURES: The results of the latency and wave amplitude of sympathetic skin response were compared between the patients with myasthenia gravis and normal controls. RESULTS: All the 30 patients with myasthenia gravis and 30 healthy physical examinees were involved in the final analysis of results. There were no significant differences between the left and right upper and lower limbs in both the myasthenia gravis group and normal control group (P > 0.05). In the myasthenia gravis group, the abnormal rate of sympathetic skin response was 37% (11/30), the latency was prolonged and the wave amplitude was decreased as compared with those in the normal control group, and there were significant differences (P < 0.01). CONCLUSION: Sympathetic skin response can be used as an electrophysiological index for judging the damages of autonomic nerve function in patients with myasthenia gravis.     

Single fiber electromyography in myasthenia gravis during pregnancy

We report the use of single fiber electromyography (SFEMG) to demonstrate changes in the physiologic abnormality of myasthenia gravis (MG) during pregnancy. A 23-year-old became pregnant 15 months after the onset of mild ocular weakness. On initial evaluation, SFEMG jitter measurements demonstrated a slight abnormality of neuromuscular transmission. There was no change in severity of clinical disease or jitter measurements until the third trimester, when she improved. Jitter measurements at that time were normal. Labor was normal and she delivered a normal male. Three days postpartum, myasthenic weakness recurred temporarily and jitter measurements showed worsening. At 16 days and 6 weeks postpartum, she had only minimal medial rectus weakness and jitter studies were normal. Three months postpartum, ocular symptoms recurred and jitter measurements were slightly abnormal. She continued to worsen, developing limb muscle and severe ocular muscle weakness at 4 months postpartum. She was treated with plasma exchange and thymectomy. Prednisone was added 2 months after thymectomy due to continued worsening and development of oropharyngeal weakness. Three years postpartum she was taking prednisone 10 mg every other day and had only slight weakness of neck flexors, and jitter studies were again normal. © 1993 John Wiley & Soncs, Inc.