Determination and clinical significance of serum anti-ryanodine receptor antibody in patients with myasthenia gravis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the clinical significance of serum anti-ryanodine receptor (RyR) antibody in the diagnosis of myasthenia gravis (MG).</p><p><b>METHODS</b>The crude sarcoplasmic reticulum was prepared from rabbit skeletal muscle, and then purified by differential centrifugation to produce the antigen. The serum anti-RyR antibody levels in 74 patients with MG (including 21 patients with comorbidic thymomas) were determined with ELISA.</p><p><b>RESULTS</b>Western blot demonstrated the presence of RyR in purified crude sarcoplasmic reticulum. The positive rate of anti-RyR antibody was significantly higher in MG patients who had comorbidic thymoma compared with those who had no such comorbidity (P < 0.01). Also, the positive rate was closely correlated with the severity of MG.</p><p><b>CONCLUSION</b>Serum anti-RyR antibody test is helpful in the diagnosis of MG associated with thymoma and can be used to judge the outcome of MG.</p>

Tumor necrosis factor-alpha polymorphism and secretion in myasthenia gravis / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To analyze the relationship between tumor necrosis factor-alpha (TNFalpha) gene promoter -308 polymorphism and myasthenia gravis (MG) in Chinese and analyze secretion of TNFalpha in peripheral blood mononuclear cells (PBMC) in MG patients.</p><p><b>METHODS</b>A biallelic polymorphism at position -308 in the promoter of TNFalpha gene was screened by PCR amplification and NcoI recognition site. One hundred and twenty-three MG cases and 115 healthy controls were included in this study. MG patients were classified to different groups according to clinical type, age at onset, and sex respectively. PBMC were isolated from 20 patients and 20 healthy controls, and then cultured in the presence or absence of phytohemagglutinin (PHA) and acetycholine receptors (AchR). The supernatants were harvested after incubation and stored until TNFalpha was assayed by enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>The frequency of TNFalpha-308 allele 2 (A) was found significantly increase in MG patients and showed a trend especially in late onset (> or =40 years) and male patients (P < 0.05). The allele A had no relationship with thymic pathogenesis in MG patients. But frequency of allele A was significantly higher in general type than in ocular type (P < 0.05). MG patients had a higher inducible level of TNFalpha by PHA and AchR, and could be down regulated after treatment.</p><p><b>CONCLUSION</b>Polymorphism in TNFalpha gene promoter -308 is associated with onset of MG. The microsatellite allele TNFalpha2 confer risk for the development of MG in Chinese patients. MG patients have a higher inducible level of TNFalpha.</p>

Serum anti-titin antibody in patients with myasthenia gravis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the clinical significance of serum anti-titin antibody level in the diagnosis of myasthenia gravis (MG) with thymoma.</p><p><b>METHOD</b>The serum anti-titin antibody was analysed by ELISA method in 40 cases of health control group, 90 cases of MG, 17 cases of MG with thymoma and 7 cases of no-MG thymoma. The positive rate was compared among these groups.</p><p><b>RESULTS</b>The positive rate of anti-titin antibody was significantly higher in MG with thymoma patients than MG patients (94% and 3%, P < 0.01). According to the Osserman's classification, anti-titin antibody was present mostly in patients (43%) in IV stage, and also present in 2 cases of 7 who with no-MG thymoma.</p><p><b>CONCLUSION</b>Serum anti-titin antibody test is helpful in the diagnosis of MG with thymoma.</p>

Clinical significance of myasthenia gravis-related autoantibodies / 中华神经科杂志

Objective To investigate the clinical significance of myasthenia gravis (MG) associated autoantibodies.Methods Titin,ryanodine receptor (RyR)and acetylcholine receptor (AChR) antibodies were examined in the sera of 74 myasthenia gravies patients by ELISA.Results AChR,Titin, RyR antibodies were detected in 77.0% (57/74),39.2% (29/74) and 32.4% (24/74) of the MG patients,respectively.For thymoma MG,AChR,Titin and RyR antibodies were detected in 76.2% (16/21),71.4% (15/21) and 52.4% (11/21) respectively.For late onset MG,Titin and RyR antibodies were detected in 77.3% (17/22) and 50.0% (11/22) respectively.With respect to the modified Osserman classification,the positve rate for Titin and RyR antibodies is much higher in more severe patients (X~2= 16.094,P=0.001;X~2=11.226,P=0.011).Titin antibodies was significantly related with RyR antibodies (r=0.380,P=0.001).Conclusions Titin and RyR antibodies show high sensitivity for thymoma MG,and the combination of serological and radiological testing can increase both sensitivity and specificity in diagnosis of thymoma MG.The levels of the two antibodies may serve as important prognosis markers in MG.The induction of the immune response against Titin and RyR and the possible pathogenic effects of the two antibodies will be further studied.