Presence Of Thymoma Research Articles

Serological and experimental studies in different forms of myasthenia gravis.

Antibodies to the acetylcholine receptor (AChR) have been recognized for over 40 years and have been important in the diagnosis of myasthenia gravis (MG), and its recognition in patients of different ages and thymic pathologies. The 10-20% of patients who do not have AChR antibodies are now known to comprise different subgroups, the most commonly reported of which is patients with antibodies to muscle-specific kinase (MuSK). The use of cell-based assays has extended the repertoire of antibody tests to clustered AChRs, low-density lipoprotein receptor-related protein 4, and agrin. Autoantibodies against intracellular targets, namely cortactin, titin, and ryanodine receptor (the latter two being associated with the presence of thymoma), may also be helpful as biomarkers in some patients. IgG4 MuSK antibodies are clearly pathogenic, but the coexisting IgG1, IgG2, and IgG3 antibodies, collectively, have effects that question the dominance of IgG4 as the sole pathologic factor in MuSK MG. After a brief historical review, we define the different subgroups and summarize the antibody characteristics. Experiments to demonstrate the in vitro and in vivo pathogenic roles of MuSK antibodies are discussed.

Low conversion rate of ocular to generalized myasthenia gravis in Singapore.

Ocular myasthenia gravis (OMG) is a common condition of the neuromuscular junction that may convert to generalized myasthenia gravis (GMG). Our aim in this study was to determine the conversion rate and predictive factors for generalization in OMG, in an Asian population. The investigation consisted of a retrospective study of OMG patients with a minimum 2 years of follow-up. Among 191 patients with OMG, 155 had the minimum 2-year follow-up. The conversion rate at median follow-up (40.8 months) was 10.6% (95% confidence interval 7.9%-13.3%), and at the 2-year follow-up it was 7.7% (95% confidence interval 5.6%-9.8%). At baseline, the predictive factors for generalization were positive acetylcholine receptor antibodies (hazard ratio 3.71, P = 0.024), positive repetitive nerve stimulation (RNS) studies (hazard ratio 4.42, P = 0.003), and presence of radiologically presumed or pathologically confirmed thymoma (hazard ratio 3.10, P = 0.013). The conversion rate of OMG to GMG in Asian patients is low, as predicted by presence of acetylcholine receptor antibodies, presence of thymoma, and positive RNS studies. Muscle Nerve 57: 756-760, 2018.

Different neurologic outcomes of myasthenia gravis with thymic hyperplasia and thymoma after extended thymectomy: A single center experience

This study aimed to reveal the clinical course and outcomes of myasthenia gravis (MG) in patients with thymic lymphoid hyperplasia and thymoma undergoing extended thymectomy and to identify the clinical prognostic factors of remission for MG. In total, 73 patients undergoing extended thymectomy were divided into two groups: group A with lymphoid hyperplasia (n=39) and group B with thymoma (n=34). According to the MG Foundation of America (MGFA) post-intervention status, the primary endpoint was a composite measure defined as achievement of complete stable remission (CSR), pharmacologic remission (PR), minimal manifestations (MM) or improvement (IM). The secondary endpoint was CSR. The cumulative probabilities of reaching the primary endpoint were 71.8% in group A and 85.3% in group B (p=0.164), respectively. Using Kaplan-Meier survival analysis, the probability of reaching the primary endpoint in group B was remarkably greater than group A (p=0.036). Cox multivariate analysis indicated that pre-operative MGFA class I (HR: 3.019, 95% CI: 1.084–8.410) and MGFA II (2.665, 95% CI: 1.033–6.873) compared to MGFA III and presence of thymoma (HR: 2.229, 95% CI: 1.079–4.606), showed the most consistent association with remission of MG after thymectomy. Finally, thymic lymphoid hyperplasia and severe symptoms may negatively affect prognosis of MG following thymectomy.

Antibodies to striated muscle and acetylcholine receptors in evaluation of surgical treatment outcomes in patients with autoimmune myasthenia gravis

OBJECTIVE. The authors evaluated the role of antibodies to striated muscle and acetylcholine receptors in diagnostics of myasthenia gravis and thymoma, as well as outcomes of thymectomy and prognosis of myasthenia course. MATERIAL AND METHODS. The study investigated correlations of antibody content to striated muscles and acetylcholine receptors from the presence and size of thymoma, myasthenia in 157 patients with various pathologies of the thymus. The dynamics of antibody concentrations was followed up after thymectomy. RESULTS. Antibody titer to striated muscle depended on the presence and size of thymoma, severity of myasthenia and changed after thymectomy. Concentration of antibodies was associated with the presence of thymoma and it didn’t change after surgical treatment. Thymoma wasn’t revealed in patients who were seronegative to both antibodies. CONCLUSIONS. Seropositivity according to one of antibody could indicate the presence of thymoma, but its absence to both antibodies allowed doctors to eliminate this diagnosis. Antibodies to acetylcholine receptors are important markers of myasthenia. Monitoring of antibody titer dynamics to striated muscles after thymectomy could be useful for assessment of response to surgical treatment and prognosis of course of myasthenia.

Criteria for Postoperative Mechanical Ventilation After Thymectomy in Patients With Myasthenia Gravis: A Retrospective Analysis

To determine the criteria for postoperative mechanical ventilation after thymectomy in patients with Myasthenia Gravis. Retrospective study. Teritiary care centre. 77 Myasthenia gravis patients operated for thymectomy were studied. After obtaining clearance from Institutional ethics committee, medical records of 77 patients with MG, who were operated for thymectomy between January 2005 and December 2015 were reviewed in a retrospective manner. Perioperative variables collected from the patient records were demographic data, duration of the disease, Osserman and Genkin classification, Anti-acetylcholine antibody (AChR) positivity, preoperative daily dose of drug, history of preoperative myasthenic crisis, preoperative vital capacity, technique of anesthesia, drugs used for anesthesia, perioperative complications, and duration of postoperative mechanical ventilation. The patients were divided into two groups, group I and group II consisting of those who required postoperative ventilation for < 300 minutes and > 300 minutes, respectively. The determinants of prolonged postoperative ventilation were studied. The requirement of mechanical ventilation was higher in patients with higher Osserman's grade of myasthenia gravis. Duration of the disease had no effect on the duration of mechanical ventilation in myasthenic patients post thymectomy (p = 0.89). The patients with a preoperative history of myasthenic crisis had a requirement for prolonged mechanical ventilation (p=0.03). Patients with preoperative vital capacity < 2.9 litres and preoperative CT scan showing thymoma had a requirement for prolonged mechanical ventilation with p values < 0.001 and 0.035, respectively. Patients who showed positivity for anti-acetylcholine antibodies had a prolonged mechanical ventilation (p=0.026). Preoperative dose of pyridostigmine and the choice of continuation or discontinuation of antcholinesterases on the day of surgery had no influence on the duration of mechanical ventilation (p value of 0.19 and 0.36 respectively). Epidural analgesia intra and postoperatively significantly reduced the requirement of mechanical ventilation (p=0.006). The predictors of postoperative ventilation in myasthenic patients undergoing thymectomy as per our study are: 1. Grade of myasthenia; 2. History of preoperative myasthenic crisis; 3. Anti-acetylcholine antibodies positivity; 4. Presence of thymoma; and 5. a vital capacity < 2.9 litres. Use of thoracic epidural as a part of combined anesthetic technique helps to reduce the need of mechanical ventilation in these patients.

Response to treatment of myasthenia gravis according to clinical subtype

BackgroundWe have previously reported using two-step cluster analysis to classify myasthenia gravis (MG) patients into the following five subtypes: ocular MG; thymoma-associated MG; MG with thymic hyperplasia; anti-acetylcholine receptor antibody (AChR-Ab)-negative MG; and AChR-Ab-positive MG without thymic abnormalities. The objectives of the present study were to examine the reproducibility of this five-subtype classification using a new data set of MG patients and to identify additional characteristics of these subtypes, particularly in regard to response to treatment.MethodsA total of 923 consecutive MG patients underwent two-step cluster analysis for the classification of subtypes. The variables used for classification were sex, age of onset, disease duration, presence of thymoma or thymic hyperplasia, positivity for AChR-Ab or anti–muscle-specific tyrosine kinase antibody, positivity for other concurrent autoantibodies, and disease condition at worst and current. The period from the start of treatment until the achievement of minimal manifestation status (early-stage response) was determined and then compared between subtypes using Kaplan-Meier analysis and the log-rank test. In addition, between subtypes, the rate of the number of patients who maintained minimal manifestations during the study period/that of patients who only achieved the status once (stability of improved status) was compared.ResultsAs a result of two-step cluster analysis, 923 MG patients were classified into five subtypes as follows: ocular MG (AChR-Ab-positivity, 77%; histogram of onset age, skewed to older age); thymoma-associated MG (100%; normal distribution); MG with thymic hyperplasia (89%; skewed to younger age); AChR-Ab-negative MG (0%; normal distribution); and AChR-Ab-positive MG without thymic abnormalities (100%, skewed to older age). Furthermore, patients classified as ocular MG showed the best early-stage response to treatment and stability of improved status, followed by those classified as thymoma-associated MG and AChR-Ab-positive MG without thymic abnormalities; by contrast, those classified as AChR-Ab-negative MG showed the worst early-stage response to treatment and stability of improved status.ConclusionsDifferences were seen between the five subtypes in demographic characteristics, clinical severity, and therapeutic response. Our five-subtype classification approach would be beneficial not only to elucidate disease subtypes, but also to plan treatment strategies for individual MG patients.

SPECIFIC FEATURES OF ANESTHESIA IN PATIENTS WITH MYASTHENIA GRAVIS.

Myasthenia gravis is an autoimmune disease caused by antibodies leading to the destruction of nicotinic acetylcholine receptors on the neuromuscular junction. It is characterized by muscle weakness that gets aggravated with physical activity and improves at rest. Myasthenia Gravis Foundation of America made the clinical classification of Myasthenia gravis which is still in use today. "Tensilon test" is still the gold standard for the diagnosis of Myasthenia gravis. In addition to this test repeated muscular stimulation can be used as well as the analysis of specific autoantibodies. Treatment of Myasthenia Gravis. In conservative treatment of Mysthenia gravis anticholinesterases, immunosuppressants and plasmapheresis can be used. If conservative treatment does not lead to the desired remission, surgical treatment is indicated. The most accepted indication for thymectomy is the presence of thymoma with generalized form of Myasthenia gravis in adults. How to Distinguish Myasthenic From Cholinergic Crisis.'The following is important to make a difference between these two crises: knowledge of the events that preceded the crisis, the size of pupils as well as the presence of muscarinic signs and tensilon test. Specific Features of Anesthesia in Patients with Myasthienia Gravis. Mechanism of the disease development is the reason'for the increased sensitivity or resistance of these patients to certain types of drugs used in anesthesia. Protocol of Perioperative Anesthesia in Patients with Myasthenia Gravis. Based on 35 years of experience in the surgical treatment of patients with Myasthenia gravis anesthesiologists at the Department of Thoracic Surgery, Institute for Pulmonary Diseases of Vojvodina. made the protocol of anesthesia and perioperative treatment for these patients. Anesthesiologists may have to deal with a patient with myasthenia gravis in different types of surgical interventions. The protocol for anesthesia and perioperative management of these patients herewith presented may greatly help them in their clinical practice.

Clinical and immunological features and treatment of myasthenia gravis in the elderly (review)

A literature review on the peculiarities of the diagnosis, course and treatment of myasthenia gravis in the elderly has been done. Despite the fact that myasthenia gravis is a disease of the young and middle-aged, in recent years, several authors observe an increased incidence among the elderly. A proper diagnosis in this age group tend to cause difficulties, and concomitant diseases complicate the choice of therapeutic approach which includes: acetylcholinesterase inhibitors, steroids, immunosuppressants, intravenous immunoglobulins and plasmapheresis. Thymectomy in older age groups, except for the presence of thymoma, due to side effects and the lack of a strong evidence base, is not widely held. The question of the effectiveness and optimal therapeutic approach of myasthenia gravis in elderly patients is still not fully resolved.

Eight-year follow-up of patients with myasthenia gravis after thymectomy.

To depict the long-term outcome of patients with myasthenia gravis after thymectomy in combination with immunotherapy, and the factors that may potentially affect the outcome. The 306 patients with myasthenia gravis who underwent extended thymectomy from January 1984 to December 2011 at Tongji Hospital were retrospectively evaluated. The patients consisted of 174 cases with thymoma and 132 cases without thymoma. Pharmaceutical treatment was tailored for each case during follow-up. Nine patients with thymomatous myasthenia gravis died during the perioperative period, and 297 patients were followed for 8.6 years. By their latest visits, 241 patients (81.1%) gained satisfactory efficacy, 24 cases died (8.1%), and 32 cases (10.8%) remained unchanged or deteriorated. Favorable factors for satisfactory efficacy included the presence of ocular myasthenia gravis before operation, no presence of thymoma, and lack of concomitant diseases. It is interesting to mention that, patients with non-thymomatous myasthenia gravis obtained significantly higher rates of complete stable remission and clinical remission than the patients with thymomatous myasthenia gravis. Extended thymectomy combined with immunotherapy is a preferred treatment with a satisfactory long-term remission rate. Patients with non-thymomatous myasthenia gravis have a much more promising prognosis than the patients with thymomatous myasthenia gravis. However, appropriate caution must be taken to discontinue pharmaceutical therapy as relapse remains a major concern after a patient who has already undergone thymectomy becomes symptom-free.

The association of PTPN22 R620W polymorphism is stronger with late-onset AChR-myasthenia gravis in Turkey.

A functional single nucleotide polymorphism (SNP) of the PTPN22 gene encoding a protein tyrosine phosphatase has been associated with autoimmune disorders including myasthenia gravis (MG). As the PTPN22 R620W polymorphism has a wide variation of allele frequencies among different populations, this polymorphism was investigated in MG in Turkey. An emphasis is put on MG subgroups according to autoantibody (Abs) production and presence of thymoma. DNA samples from 416 patients with clinically diagnosed generalized MG (231 with Abs to acetylcholine receptor, AChR-MG), 53 with Abs to muscle-specific kinase (MuSK-MG), 55 patients with no detectable Abs (SN-MG), 77 patients with thymoma (TAMG) and 293 healthy controls (HC) were genotyped for the SNP (PTPN22 R620W, C1858T, rs2476601). The PTPN22 T allele was increased in AChR-MG patients (odds ratio [OR]: 2.5, 95%CI: 1.2–5.1). The association was stronger in late disease-onset AChR (LOMG, OR: 3.1, 95%CI: 1.2–8.2). MuSK-MG, SN-MG and TAMG groups did not carry the variant allele more frequently than the HC. In contrast to findings in other autoimmune diseases, the distribution of the PTPN22 polymorphism in this population provides a susceptibility marker for AChR-MG. The strongest association is detected in patients with LOMG.

Risk factors of myasthenic crisis after thymectomy in 178 generalized myasthenia gravis patients in a five-year follow-up study

Purpose: The aims of this study were to assess the clinical characteristics of patients with postoperative myasthenic crisis (PMC) and to identify the risk factors affecting the occurrence of PMC. Method: Extended thymectomy was performed on 178 patients with generalized MG with a mean onset age of 36.8 years. The potentially risk factors were analyzed by binary logistic regression analysis. Result: During the over five-year follow-up, 44 patients (24.7%) experienced 58 episodes of PMC. The mean interval between surgery and the first episodes of PMC was 13.8 months, and for 81.8% of the patients it occurred within the first 2 years after thymectomy. Nine of 16 patients (56.3%) with a history of preoperative MC had recurrent crises. Respiratory tract infection was the most common precipitant of PMC. Univariate analysis showed that age at onset, preoperative MGFA class, preoperative MC, presence of bulbar symptoms, operation duration, amount of intraoperative blood loss, and the presence of thymoma were significantly associated with the occurrence of PMC. However, multivariate logistic regression analysis revealed that a history of preoperative MC (OR = 2.845, p = 0.044), presence of bulbar symptoms (OR = 3.062, p = 0.027), and longer operation duration (OR = 1.026, p = 0.009) were the independent risk factors for PMC. Conclusion: The important risk factors for developing PMC in generalized MG patients include the presence of bulbar symptoms, history of preoperative MC, and longer operation duration. Optimization of the preoperative evaluation and proper perioperative care of MG patients may decrease the frequency of PMC.

Predictors of outcome of myasthenic crisis

There is paucity of study on predictors of myasthenic crisis (MC), prolonged ventilation and their outcome, a reason why this study was undertaken. Sixty-four patients with myasthenia gravis (MG) were included whose median age was 45 (6-84) years. Their clinical treatment, presence of thymoma, anti-acetylcholine receptor antibody (AchRAb), thymectomy, comorbidities, offending drugs and occurrence of MC were noted. Patients needing prolonged ventilation (>15 days) were noted. Hospital mortality, MG quality of life (QOL) at discharge and thereafter annual hospital visit, admission, expenditure and work day loss were enquired. Fourteen (21.9 %) patients had MC within 1-120 (median 8.5) months of disease onset within a median follow-up of 48 (3-264) months. The precipitating factors were infection in six, surgery in five, tapering of drugs in two and reaction to iodinated contrast in one patient. Male gender, bulbar weakness, AchRAb, thymoma, surgery and comorbid illnesses were related to MC. Eight of them (57.1 %) needed prolonged ventilation. Half the patients with MC had recurrent crisis (2-4 attacks). Death was not related to MC although MC patients had worse QOL, higher annual treatment expenditure with frequent hospital visit and hospitalization. In conclusion, association of comorbid illness with MC and prolonged ventilation highlights the need of close follow-up and appropriate management.

Thymoma in Myasthenia Gravis: From Diagnosis to Treatment

One half of cortical thymoma patients develop myasthenia gravis (MG), while 15% of MG patients have thymomas. MG is a neuromuscular junction disease caused in 85% of the cases by acetylcholine receptor (AChR) antibodies. Titin and ryanodine receptor (RyR) antibodies are found in 95% of thymoma MG and 50% of late-onset MG (MG onset ≥50 years), are associated with severe disease, and may predict thymoma MG outcome. Nonlimb symptom profile at MG onset with bulbar, ocular, neck, and respiratory symptoms should raise the suspicion about the presence of thymoma in MG. The presence of titin and RyR antibodies in an MG patient younger than 60 years strongly suggests a thymoma, while their absence at any age strongly excludes thymoma. Thymoma should be removed surgically. Prethymectomy plasmapheresis/iv-IgG should be considered before thymectomy. The pharmacological treatment does not differ from nonthymoma MG, except for tacrolimus which is an option in difficult thymoma and nonthymoma MG cases with RyR antibodies.

Myasthénies oculaires : diagnostic et traitement

Myasthenia gravis is a rare, auto-immune disorder of the neuromuscular junction. Onset signs frequently involve ocular muscles, accounting for ptosis and/or diplopia in more than 75% of cases. Among the cases with purely ocular muscle involvement, less than one half will never progress towards a more general form of myasthenia. However, even if they do not share the potentially life-threatening course of generalized myasthenia, purely ocular forms are often responsible for severe impairment in everyday life. The diagnosis is essentially based on fluctuations in the time and topography of the ocular muscle weakness. It still remains uneasy, as investigations such as electromyography, search for antiacetycholine receptor antibodies (positive in 50% of cases of purely ocular myasthenia), and edrophonium chloride test sometimes yield false negative results. Whereas some patients get better while on anticholinesterasic drugs alone, most of them will experience insufficient improvement and need steroids and/or immunosuppressant drugs. There is no indication for plasma exchanges, intravenous immunoglobulin or thymectomy (except in the presence of thymoma). This treatment could well decrease the risk of an evolution towards generalized myasthenia. The reasons underlying the vulnerability of ocular motor muscles in myasthenia are complex and several factors (linked to immunology, anatomy and function) may combine to bring about their specific involvement. In the future, randomized, controlled trials will be necessary, in order to determine a more rational approach of the treatment of ocular myasthenia, which currently lies mostly on retrospective data and the expertise of reference centers implicated in the management of the disease.

Treatment of Myasthenia Gravis

Myasthenia gravis (MG) is an antibody-mediated, neuromuscular transmission disorder, which ranges in clinical manifestations of ocular myasthenia that may be visually disabling to myasthenic crisis with patients suffering life-threatening respiratory insufficiency. MG also has pathophysiologic subgroups based on presence or absence of acetylcholine receptor or muscle-specific kinase antibodies and presence of thymoma. Cholinesterase inhibitors partially improve weakness, but the vast majority of patients require therapies that moderate the autoimmune attack. Mortality of MG has been reduced over the last century, but adverse effects of treatment compromise patient care and rigorous evidence to guide the clinician are lacking.

Clinical Outcome of Video-Assisted Thymectomy for Myasthenia Gravis and Thymoma

We reviewed our experience of video-assisted thoracoscopic thymectomy for myasthenia gravis and thymomas in 119 patients, aged 12-83 years, who were treated between 1998 and 2007. Disease severity was graded using the Osserman classification. To prevent rupture of the tumor capsule and tumor seeding, thymomas were resected using a modified no-touch technique. Thymoma diameters were 10-90 mm (mean, 50 mm). There were no operative deaths, 12 (10%) patients had complications, and 87 (73.1%) improved by 1 or more Osserman grades postoperatively. After follow-up of 1.9-10 years (mean, 4.9 years), 74 (62%) patients remained asymptomatic, with 21% in complete stable remission. Using multivariate regression analysis, there were no statistical differences in median pre- and postoperative Osserman grades with regards to age, sex, duration of symptoms, and presence of thymoma. Video-assisted thoracoscopic thymectomy for myasthenia gravis and selected thymomas can achieve long-term clinical outcomes comparable to those of standard approaches.

Factors associated with response to calcineurin inhibitors in myasthenia gravis

The objective was to assess which clinical factors of patients with myasthenia gravis (MG) are associated with responsiveness to calcineurin inhibitors (CNIs, cyclosporine and tacrolimus). We retrospectively analyzed the 6-month effects of CNIs in 62 MG patients. We excluded the influence of other immune treatments and determined factors associated with response to CNIs. The frequency of patients who achieved neither a > or =3-point reduction in quantitative MG score nor a > or =25% reduction in daily dose of prednisolone (poor responders) reached 35.5% (22/62) and 64.5% (40/62), respectively, compared with patients who achieved at least one of these improvements (responders). Neither dose nor blood concentration of CNIs differed between groups. Multivariate logistic regression analysis revealed time since onset of disease [odds ratio (OR) = 0.85, P = 0.005] and presence of thymoma (OR = 5.56, P = 0.05) as clinical factors that predict response to CNIs. As for MG-related autoantibody status, an autoantibody against a voltage-gated potassium channel, Kv1.4, was associated with response (OR = 9.01, P = 0.04) and showed a correlation with the presence of thymoma (P < 0.01). In MG, the early stages of disease and thymoma-associated MG are responsive to treatment with CNIs.

Extended Transsternal Thymectomy for Myasthenia Gravis: a Report of 19 Consecutive Cases

Background : Thymectomy is considered as an effective therapeutic option for patients with myasthenia gravis (MG). This study reports the experience of our centre’s investigation into the efficacy and the safety of the procedure and the influence of different pre-operative factors on the surgical outcome.Methods : A retrospective chart review/interview was made of 19 consecutive patients who underwent extended transsternal thymectomy for MG from 1992 to 2003. The severity of the disease was determined according to the Osserman Classification. Efficacy was measured by determining the change in clinical status, the rate of remission during follow-up, and the reduction in medication requirements after thymectomy. Complete remission (CR) was defined as asymptomatic off medication for 6 months. The CR rate was calculated using the Kaplan-Meyer method. Results : The mean age of the patients at surgery was 34 years (range, 9–63) and 78.9% were female. Mean length of follow up was 86 months (range, 24–163). The overall complication rate was 10.6% (1 episode of atrial fibrillation and a left recurrent laryngeal nerve palsy that resolved after the first postoperative month). There was no operative mortality. The mean hospital stay was 9.4 days (range, 5–23). The crude CR rate was 32% (n = 6). The Kaplan-Meier estimate of CR was 42% at 6 years. Age, gender, duration of symptoms, thymic histology, Osserman stage and the presence of thymoma were not identified as prognostic variables. The average daily dose of Medrol® and Mestinon® decreased significantly between the pre-operative period and the last follow-up (Medrol®, p = 0.0081; Mestinon®, p = 0.0013).Conclusions : Transsternal thymectomy for MG is safe and effective. It benefits patients with MG at all stages. Patients with thymoma are not associated with poorer remission rates. Complete responses are durable, as the CR rate remains stable over time.

Neurologic outcomes of thymectomy in myasthenia gravis: Comparative analysis of the effect of thymoma

The objectives of this study were to compare the clinical features and the outcomes after thymectomy between patients with and without thymoma and to evaluate the influence of thymectomy on the subsequent clinical course of myasthenia gravis. Between 1995 and 2003, 64 consecutive patients underwent thymectomy, and of these, 60 patients were followed up for at least 12 months postoperatively. The study population was divided into 2 groups based on the presence of thymoma. We performed a retrospective analysis to compare the neurologic outcomes of thymectomy between patients with thymomatous myasthenia gravis and those with nonthymomatous myasthenia gravis. Twenty-four patients had a thymoma. No significant differences were observed between the 2 groups regarding the preoperative severity of myasthenia gravis. There was no significant difference in the follow-up duration between the 2 groups. There was no significant difference in the overall remission rate between the 2 groups (P = .064). The mean time required to reach a remission was 10.6 months and 23.5 months in the thymoma and nonthymoma groups, respectively. The mean duration of remission was 43.1 months and 30.8 months in the thymoma and nonthymoma groups, respectively. In the early phase of follow-up, more patients reached remission in the thymoma group than those in the nonthymoma group (P = .040). Neurologic outcomes of the thymoma group were no worse than those of the nonthymoma group. It is expected that earlier thymectomy is likely to result in a better prognosis by shortening the disease period, even for patients with nonthymomatous myasthenia gravis.

Polymorphisms of interferon-γ, interleukin-10, and interleukin-12 genes in myasthenia gravis

To assess the involvement of polymorphisms in genetic susceptibility to myasthenia gravis (MG), this study analyzed four polymorphisms of interferon (IFN)-gamma, interleukin (IL)-10, and IL-12 genes in 115 patients and 204 healthy controls (HC). IFNG +874T carriers were less frequent in MG, in patients with anti-acetylcholine receptor (AChR) (63%) and anti-titin (56.2%) antibodies compared with HC (p = 0.01 for all, OR: 0.5, 0.5, and 0.4, respectively). The presence of thymoma was also associated with lower frequency of IFNG +874T allele (p = 0.018, OR = 0.34). At IL10, -2763A allele was found to be slightly more frequent in MG and in patients with anti-AChR than in HC group (p = 0.05, OR = 1.7, p = 0.036, OR = 1.83). However, these associations did not remain significant after correction for multiple comparisons. IL12B allele distribution was not different among groups. These data suggest that some cytokine gene polymorphisms may contribute to susceptibility to or antibody production in MG. These findings need to be replicated in further studies.