Analysis of clinical features and outcomes in patients with ocular myasthenia gravis according to anti-acetylcholine receptor antibody-seropositivity.

PURPOSE: To comparatively analyze the clinical characteristics of patients with ocular myasthenia gravis (OMG) referred to an ophthalmology clinic, according to anti-acetylcholine receptor antibody (AchR Ab)-seropositivity. STUDY DESIGN: Retrospective Cohort Study. METHODS: Medical records of patients with OMG who presented to a tertiary eye care center between 2003 and 2020 were retrospectively reviewed. Demographics, ophthalmologic characteristics, response to medical treatment, presence of autoimmune thyroid disease and thyroid autoantibody were compared between the AchR Ab seropositive and seronegative groups. RESULTS: A total of 130 patients with OMG were identified; among them, 46 patients (35.4%) had autoantibody against acetylcholine receptors. The mean age at symptom onset was 42.4 ± 18.9 years. There were no differences in mean age at symptom onset, gender ratio, and mean follow-up period between patients with seropositive and seronegative OMG. Graves ophthalmopathy was significantly more frequent in seronegative patients (p = 0.04), while thymic disease (p < 0.01) was more frequent in seropositive patients (p < 0.01). Among patients with seropositive OMG, 52.3% showed a good response to medical treatment, while only 31.4% of the seronegative patients were classified as good responders (p = 0.01). Thyroid dysfunction was found in 27.4% patients with OMG and the proportion of thyroid dysfunction was not different according to anti-acetylcholine receptor antibody-seropositivity. CONCLUSION: Seropositivity to acetylcholine receptor antibody is associated with a better response to medical treatment and lower risk of concomitant autoimmune thyroid disease in patients with OMG.

A Bead-Based Nonradioactive Immunoassay for Autoantibody Testing in a Mouse Model of Myasthenia Gravis.

Serological testing for anti-acetylcholine receptor (AChR) autoantibodies is not only crucial for the diagnosing, disease monitoring, and treatment management of patients with myasthenia gravis (MG) but also for preclinical studies utilizing MG disease models. However, there are no specific guidelines on which methods to use in clinical diagnostic or research laboratories to detect or quantify any MG-specific autoantibodies. Conventional autoantibody assays, particularly those for anti-AChR antibodies, are varied and mostly laboratory-specific. Here, we report our new nonradioactive immunoprecipitation-immunoblotting method for assessing autoantibodies (anti-AChR antibodies) in a mouse model of MG. This simple, efficient, reproducible, and cost-effective assay appears superior to the enzyme-linked immunosorbent assay but comparable to the radioimmunoprecipitation or cell-based assay in specificity and sensitivity. Thus, the newly developed assay can serve as a valuable alternative to classical assays and is suitable for routine testing of AChR-specific autoantibodies in preclinical studies. The further optimization of our assay may facilitate its application in the diagnosis and therapeutic management of patients with MG.

Thymoma Exhibiting Spontaneous Regression With Cystic Change Due to Acute Infarction: A Case Report and Literature Review.

Spontaneous regression (SR) of thymoma is rare. We report a case of a surgically resected thymoma due to cystic changes owing to acute ischemic infarction with an increased anti-acetylcholine receptor antibody level. A 61-year-old male underwent a computed tomography (CT) scan, which showed a 4.9 cm anterior mediastinal tumor and slight right pleural effusion. Blood test results indicated an elevated white blood cell count of 13300/mL. One month later, an enhanced CT scan at our hospital showed spontaneous mediastinal tumor regression to 3.7 cm and no pleural effusion. The tumor contained homogeneous low-density areas on enhanced CT, which showed high intensity on T2-weighted magnetic resonance imaging, indicating cystic changes. He had no symptoms of myasthenia; however, his anti-acetylcholine receptor antibody level was slightly elevated (0.4 nmol/L). Suspecting a thymoma, an extended total thymectomy through a median sternotomy was performed. Histopathological analysis confirmed the diagnosis of thymoma type B2 and Masaoka stage I. SR is due to acute intratumoral infarction. At two years postoperatively, no tumor recurrence or development of myasthenia gravis was observed. Thymomas should be included in the differential diagnosis of anterior mediastinal tumors that regress spontaneously with cystic changes, pleural effusion, and an elevated inflammatory response. Mature cystic teratoma rupture should be differentiated, but preoperative biopsy is often challenging owing to necrotic and fibrous tissues; therefore, early surgical resection is required for diagnosis and treatment.

[A case of anti-acetylcholine receptor antibody-positive ocular myasthenia gravis with anti-titin antibody and anti-Kv1.4 antibody positive inflammatory myopathy].

An 84-year-old man was diagnosed with anti-acetylcholine receptor (AChR) antibody-positive ocular myasthenia gravis (OMG) at the age of 77 and received treatment. The patient was referred to our department with swelling and pain in his right upper arm, which had spread to other limbs. His serum anti-AChR antibody and creatine kinase levels were elevated, and MRI of the limbs displayed signal changes suggesting inflammation in the several muscles. Despite showing no sign of thymoma, he was positive for serum anti-titin and anti-Kv1.4 antibodies. We performed a muscle biopsy, which led to a diagnosis of inflammatory myopathy (IM). IM associated with OMG is relatively mild. Age-related immune dysregulation may cause both OMG and IM. Evaluation of disease activity with serum anti-AChR antibody levels, and assessment of prognosis with examining anti-striational antibodies are necessary for appropriate management of IM associated with MG.

A multicentre, prospective, double-blind study comparing the accuracy of autoantibody diagnostic assays in myasthenia gravis: the SCREAM study.

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.

Clinical and immune-related factors associated with exacerbation in adults with well-controlled generalized myasthenia gravis.

Objectives: To describe the clinical predictors and immune-related factors for exacerbation in adults with well-controlled generalized myasthenia gravis (GMG). Methods: We conducted a retrospective analysis of 585 adults with well-controlled GMG from our institution to explore the risk factors for exacerbation. Furthermore, propensity score matching (PSM) was used to compare the proportions of lymphocyte subsets, and the levels of immunoglobulin, complement, and anti-acetylcholine receptor antibody (AChR-ab) in the peripheral blood of 111 patients with exacerbations and 72 patients without exacerbations. Results: A total of 404 patients (69.1%) experienced at least one exacerbation, and the median (interquartile range) time to the first exacerbation was 1.5 years (0.8-3.1 years). Multivariable Cox regression analysis showed that age at onset, disease duration before enrollment, Myasthenia Gravis Foundation of America classification (MGFA) class III vs. class II, MGFA class IV-V vs. class II, AChR-ab levels, anti-muscle specific kinase antibody levels, thymus hyperplasia, prednisone plus immunosuppressants vs. prednisone treatment, and thymectomy were independent predictors for exacerbations [hazard ratio (HR) = 1.011, 1.031, 1.580, 1.429, 2.007, 2.033, 1.461, 0.798, and 0.651, respectively]. Propensity-matched analysis compared 51 patient pairs. After PSM, the peripheral blood proportions of CD3-CD19+ B cells, ratios of CD3+CD4+/CD3+CD8+ T cells, and AChR-ab levels were significantly increased, and the peripheral blood proportions of CD3+CD8+ T and CD4+CD25+CD127low+ regulatory T cells (Tregs) were significantly lower in patients with exacerbation than in those without exacerbation (all p < 0.05). Conclusion: Myasthenia gravis (MG) exacerbations were more frequent in those patients with older onset age, longer disease duration, more severe MGFA classification, positive AChR-ab, and lack of combined immunotherapy or thymectomy treatment. On the other hand, CD3-CD19+ B cells, CD3+CD8+ T cells, Tregs, and AChR-ab in peripheral blood may be involved in the course of GMG exacerbation.

Anti-Kv1.4 Antibody Without Myasthenia Gravis: A Rare Cause of Autoimmune Myocarditis and Myositis.

Anti-Kv1.4 antibody is often detected in thymoma-associated myasthenia gravis patients with anti-acetylcholine receptor antibody. Herein, we describe 2 patients with concurrent myocarditis and myositis. In both cases, anti-Kv1.4 antibody was positive despite the absence of thymoma and anti-acetylcholine receptor antibody, and immunosuppressants eventually resolved their symptoms and cardiac function. (Level of Difficulty: Advanced.).

Clinical characteristics of anti-AChR-MuSK-LRP4 antibody-negative myasthenia gravis in China.

INTRODUCTION/AIMS: Descriptions of the clinical characteristics of anti-AChR-MuSK-LRP4 antibody-negative myasthenia gravis (triple-negative myasthenia gravis, TNMG) are lacking in the current literature. Therefore, we investigated the clinical characteristics of TNMG in Chinese patients. METHODS: We retrospectively analyzed 925 patients with MG registered in the Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences from January 2015 to March 2021. RESULTS: One hundred six patients diagnosed with TNMG were included in the study. The average age of onset was 32.4 y, with a male-to-female ratio of 1:1. The age of onset showed a bimodal distribution: 0-9 y and 40-49 y. Adult patients were more likely to have weakness of limb and bulbar muscles (p < .05). Thymic hyperplasia was found in 20.2% of the patients. Younger patients were more likely to relapse. The rate of adult early-onset myasthenia gravis reaching complete stable remission and pharmacological remission was 47.6%, and the prognosis was better than that in juvenile-onset myasthenia gravis (p = .019). Older age of onset was the only risk factor for the development of generalized TNMG from ocular TNMG (R = 1.046, p = .002, 95% confidence interval 1.017-1.077). DISCUSSION: This study showed that the clinical characteristics of patients with TNMG varied among the different age groups. Significant findings included a bimodal distribution of onset age, coexisting thymic hyperplasia, and a generally favorable prognosis.

Autologous hematopoietic stem cell transplant for the treatment of refractory myasthenia gravis with anti-muscle specific kinase antibodies.

INTRODUCTION/AIMS: Up to 25% of patients with myasthenia gravis (MG) have refractory disease despite trials of multiple immunosuppressants. Several case series describe acetylcholine receptor antibody-positive (AChR) MG patients treated with autologous hematopoietic stem cell transplant (HSCT). In this report, we describe three patients with anti-muscle-specific kinase (MuSK) MG treated with HSCT. METHODS: We included all patients who had undergone HSCT with anti-MuSK myasthenia gravis identified through the records of the Alberta Blood and Marrow Transplant Program. We collected demographic and clinical data including validated MG scales as well as questionnaire data. RESULTS: All 3 patients had severe disease (Myasthenia Gravis Foundation of America score IVb-V) and were refractory to multiple treatments, including rituximab. All patients improved with no clinical manifestations or mild symptoms and remained as such for 2, 3.5, and 5.5 y. Adverse events ranged from treatable infections and transient dyspnea to persistent fatigue and premature menopause. The average worst Myasthenia Gravis Activities of Daily Living (MG-ADL) scores improved from 14.7 before to 0.3 after HSCT. The mean worst Myasthenia Gravis Quality of Life Questionnaire (MG-QoL15) scores improved from 26.7 to 0. All patients reported they would undergo transplant again for their MG. DISCUSSION: We describe three patients with anti-MuSK MG treated with HSCT, all of whom became symptom free from MG with a tolerable side effect profile. In patients with severe refractory anti-MuSK MG, it may be reasonable to consider HSCT.

Exacerbation of Thymoma-Associated Myasthenia Gravis Following Efgartigimod Treatment Related to Anti-acetylcholine Receptor Antibody Overshoot: A Report of Two Cases.

Myasthenia gravis (MG), a chronic, autoimmune disease affecting the neuromuscular junction, arises from various autoantibodies, including those against the acetylcholine receptor (AChR). Recently, efgartigimod, a human IgG1 antibody Fc fragment engineered to reduce the pathogenic IgG autoantibody level, was developed as a treatment for MG. However, the long-term effects of the treatment are still unclear. The present report describes two novel cases of thymoma-associated MG exacerbation following efgartigimod treatment related to anti-AChR antibody overshoot. Both cases shared certain characteristics, including anti-AChR antibody positivity and post-thymectomy status. After a few cycles of efgartigimod treatment, their MG deteriorated, and their anti-AChR antibody titer exceeded the level before efgartigimod therapy. Prior studies show that anti-AChR antibody titer does not correlate with the disease severity of MG. However, previous studies have reported antibody overshoot following plasma exchange, which, like efgartigimod, reduces the level of plasma IgG and autoantibodies. Thus, MG exacerbation with anti-AChR antibody overshoot may be an adverse effect of both efgartigimod and plasma exchange. When clinical symptoms in patients with thymoma-associated MG receiving efgartigimod deteriorate despite low IgG, assessing the anti-AChR antibody level can be important for reconsidering the treatment strategy.

Increased serum IL-2, IL-4, IL-5 and IL-12p70 levels in AChR subtype generalized myasthenia gravis.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions. Cytokines play important roles in facilitating the immune response and augmenting the pathogenic antibody production. The current study aims to sensitively characterize the serum levels of cytokines with very low concentration in generalized MG (gMG). METHODS: Using ultrasensitive single-molecule arrays (SIMOA), we measured serum IL-2, IL-4, IL-5 and IL-12p70 in 228 participants including 152 immunotherapy-naïve anti-acetylcholine receptor (AChR) subtype gMG from Huashan MG registry and 76 age-matched healthy controls. Subgroup analysis was then performed by stratifying patients according to the onset ages, MGFA classification, disease duration at baseline. RESULTS: Serum IL-2, IL-4, IL-5 and IL-12p70 levels were significantly elevated in gMG compared to controls (0.179 pg/mL versus 0.011 pg/mL, P < 0.0001; 0.029 pg/mL versus 0.018 pg/mL, P = 0.0259; 0.215 pg/mL versus 0.143 pg/mL, P = 0.0007; 0.132 pg/mL versus 0.118 pg/mL, P = 0.0401). Subgroup analysis revealed that IL-2 levels were slightly elevated in gMG with MGFA II compared to MGFA III/IV (0.195 pg/mL versus 0.160 pg/mL, P = 0.022), as well as elevated levels of IL-2 (0.220 pg/mL versus 0.159 pg/mL, P = 0.0002) and IL-5 (0.251 pg/mL versus 0.181 pg/mL, P = 0.004) in late-onset gMG compared with the early-onset gMG. gMG patients with a long duration had a significant increased serum IL-12p70 than those with a short duration (0.163 pg/mL versus 0.120 pg/mL, P = 0.011). CONCLUSION: Serum IL-2, IL-4, IL-5 and IL-12p70 levels were increased in AChR subtype gMG using ultrasensitive measurement. Serum cytokines with very low concentrations may provide as potential biomarkers in stratifying gMG patients in future prospective cohort studies.

[The efficacy of eculizumab against post-thymectomy exacerbations in thymoma associated myasthenia gravis (MG)].

We report a 62-year-old woman with thymoma associated myasthenia gravis (MG). She had significant dysphagia and was treated with corticosteroids, intravenous immunoglobulin (IVIG), immunoadsorption plasmapheresis (IAPP), and immunosuppressive drugs, and the extended thymectomy. Her symptoms gradually improved, but 3 weeks after thymectomy, her bulbar symptoms recurred. Although she was treated with repeated IVIG and IAPP, her symptom remained. Finally, after starting eculizumab did her symptoms go into complete remission. This case suggests the efficacy of anti-complement therapy for postoperative exacerbation of MG.

Regulatory B Cells Are Decreased and Functionally Impaired in Myasthenia Gravis Patients.

Myasthenia gravis (MG) is an autoimmune disease mediated by B cells secreting autoantibodies. Regulatory B (Breg) cells confirmed to have an immunosuppressive function play an important role in many autoimmune diseases. However, what about the changes in Breg cells in the thymus and peripheral blood of MG patients? The changes in the proportion of Breg cells in the peripheral blood of 41 MG patients without any drug treatment and 30 healthy controls were detected by flow cytometry. We found that the proportions of CD19+ IL-10+ cells and CD19+CD24hiCD38hi cell subsets in MG patients were significantly lower than those in healthy controls. Then, we detected the proportion of CD19+ IL-10+ cells in thymus tissues of 10 healthy children, 4 healthy adults, and 12 MG patients by flow cytometry. However, the percentage of CD19+ IL-10+ cells was highest in healthy children (~8%), followed by healthy adults (~3%), and was lowest in MG patients (~0.5%). CD19+CD24hiCD38hi B cells exerted immunosuppressive functions in healthy people but were refractory in MG patients. Moreover, p-STAT3 downstream of CD40 may be impaired in CD24hiCD38hi B cells from the peripheral blood of MG patients.

Positive acetylcholine receptor antibody in nonmyasthenic patients.

INTRODUCTION/AIMS: In this study we aimed to determine the frequency of acetylcholine receptor (AChR) binding antibody positivity via neuroautoimmunity panel testing, and describe its occurrence in a group of nonmyasthenic disorders. METHODS: This is a retrospective analysis of patients who underwent neuroautoimmunity antibody panel testing from 2010 to 2018 at the Cleveland Clinic. RESULTS: A total of 10 855 patients received neuroautoimmunity antibody panel testing, and 224 (2.1%) patients were positive for AChR binding antibody. Fifty-eight patients with a known myasthenia gravis (MG) diagnosis and 11 patients with incomplete follow-up were excluded. Among the remaining 155 patients, 30 had newly diagnosed MG and 125 were nonmyasthenic. In 35 patients, MG was within the initial differential diagnosis based on the clinical presentation. In contrast to nonmyasthenic patients, myasthenic patients were more likely to have an initial clinical presentation raising suspicion for MG (73.3% vs 10.4%, P < .001), higher mean AChR binding antibody titer (8.2 ± 15.6 vs 0.4 ± 1.6 nmol/L, P = .011), and higher frequency of abnormal AChR modulating antibody (89.3% vs 23.9%, P < .001). A combination of AChR binding antibody of >0.5 nmol/L and modulating antibody of over 20% in patients with clinical suspicion of MG is virtually diagnostic of MG. A total of 31 (24.8%) nonmyasthenic patients carried coexisting autoimmune conditions. DISCUSSION: Elevated titers of AChR binding antibody can sometimes be found in nonmyasthenic patients. Combined analysis of clinical presentation, AChR binding antibody titer, and AChR-modulating antibody results can be helpful in confirming an MG diagnosis.

Roles of IL-35-producing T and B cells in anti-acetylcholine receptor antibody-positive myasthenia gravis.

BACKGROUND: Interleukin 35 (IL-35) plays an anti-inflammatory in numerous autoimmune diseases. However, the potential roles of IL-35-producing T and B cells and serum IL-35 levels in the pathogenesis of myasthenia gravis (MG) and its association with disease activity in patients with MG remain unclear. METHODS: The percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells among peripheral blood mononuclear cells were determined in 37 patients with anti-acetylcholine receptor (AChR) antibody-positive MG and 35 healthy controls (HCs) by performing a flow cytometry analysis. Serum IL-35 levels in participants were determined using an enzyme-linked immunosorbent assay. Further, the correlations between IL35 levels and disease activity were analysed. RESULTS: The percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells were significantly lower in patients with anti-AChR antibody-positive MG than in HCs (p = 0.001 and p = 0.002, respectively). Furthermore, patients with thymoma and patients with generalized MG had lower percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells than those without thymoma and those with ocular MG (p = 0.001 and p = 0.003; p = 0.008 and p = 0.001, respectively). Interestingly, the suppression of IL-35 secretion correlated negatively with the activities of daily living scores of patients with MG (r = -0.4774, p = 0.0028) and the quantitative MG scores (r = -0.4656, p = 0.0037). The proportions of IL-35-producing T cells and B cells and serum levels of IL-35 increased after treatment. CONCLUSIONS: IL-35 may represent a potential biomarker for the clinical evaluation of MG.

A Case Report and Literature Review of New-Onset Myasthenia Gravis After COVID-19 Infection.

Myasthenia gravis (MG) is an autoimmune disorder affecting the neuromuscular junction caused by a B-cell-mediated, T-cell-dependent immunologic attack at the end plate of the postsynaptic membrane. Attack on muscle acetylcholine receptors (AChR) of the postsynaptic membrane due to the AChR, muscle-specific tyrosine kinase, or lipoprotein receptor-related peptide 4 antibodies lead to symptoms of painless, fluctuating weakness of muscle groups and often begins with ocular signs and symptoms. Coronavirus disease 2019 (COVID-19) is an acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus closely related to SARS-CoV. Serious neurologic complications are infrequent and diverse with reported cases of stroke, encephalitis/meningitis, Guillain-Barré syndrome, acute disseminated encephalomyelitis, ataxia, and unspecified limb weakness. MG is a rarely reported sequela of COVID-19 infection. To date, there are 15 reported cases of post-COVID-19 MG. In this article, we present a case of post-COVID-19 MG and a concise review of other reported cases. An 83-year-old Caucasian male with a medical history of atrial fibrillation status post-ablation and non-ischemic cardiomyopathy was initially admitted for COVID-19 pneumonia. He was treated with remdesivir, convalescent plasma, and supplemental oxygen therapy but did not require invasive mechanical intubation. One month after discharge, he started experiencing fatigue with muscle weakness and progressive dyspnea. He progressed to develop dysphonia, especially at the end of the day. After extensive workup, he was diagnosed with MG with a positive antibody against the AChR. The chronological events of developing slowly worsening muscular weakness after recovering from COVID-19 infection and positive AChR antibody led to the diagnosis of post-COVID-19 new-onset MG. Post-COVID-19 fatigue, long-term use of steroids, and intensive care unit-related physical deconditioning can be confounders in the clinical presentation of post-COVID-19 new-onset MG. Careful history-taking and meticulous assessment of chronological events are needed to diagnose this rare entity.

Immunoadsorption apheresis versus intravenous immunoglobulin therapy for exacerbation of myasthenia gravis.

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.

Thymoma-Related Stiff-Person Syndrome with Successfully Treated by Surgery.

INTRODUCTION: Stiff-person syndrome (SPS) is a rare autoimmune neurological disorder. Paraneoplastic SPS associated with malignant tumors such as thymoma occurs in approximately 5% of all SPS cases. We present a rare case of thymoma accompanied by SPS successfully treated using surgery. PRESENTATION OF CASE: A 26-year-old woman presented with lower limbs convulsions and gait disturbance and complained of leg pain. Cerebrospinal fluid and blood test results showed a high level of anti-glutamic acid decarboxylase (GAD) antibodies. Computed tomography showed anterior mediastinal tumor suggestive of a thymoma. She underwent extended thymectomy, and her symptoms gradually improved after surgery. No evidence of recurrent thymoma and SPS has been observed over 44 months. CONCLUSION: Surgical treatment would be effective for patients with SPS and thymoma.

Rippling Muscle Disease with Irregular Toe Jerks and Anti-acetylcholine Receptor Antibodies: Remission after Extended Thymectomy.

We herein report a 63-year-old rippling muscle disease (RMD) patient who presented with painless stiffness, muscle hypertrophy and muscle contractions elicited by mechanical stimulation. He also showed irregular toe jerks and a slightly elevated level of anti-acetylcholine receptor antibody (AChR-Ab). Since he had a mediastinal mass mimicking thymoma, which was later revealed to be a bronchial cyst, he underwent extended thymectomy. The irregular toe jerks disappeared within a week after the operation. The other muscle symptoms completely remitted 27 months after the onset. This is the first report of a sporadic case of RMD with irregular toe jerks that resolved after extended thymectomy.