Detection Of Titin Antibodies,Ryanodine Receptor Antibodies In Myasthenia Gravis Patients And Expression Of These Receptor Epitoes In Thymoma

Objective: ① To investigate the relation between the Titin-Ab, Ryanodine receptor antibodies(RyR-Ab) and the pathogenesis of myasthenia gravis(MG); ②To study the role of the antibodies in diagnosing MG, especialy in MG with thymoma(MGT) patients;③To evaluate the clinical significance of Titin-Ab RyR-Ab in curative effect and prognosis of MG.Methods: Using ELISA and Western blot methods,we tested the titer of Titin-Ab RyR-Ab and AchR-Ab in the sera of 62 patients with MG , as well as 30 cases non-MG with other neurologic(NMG) disorders and 50 normal controlsfNC) from October 2002 to January 2005; And in 10 cases of patients with MG the antibodies were retested after therapy.Results: ELISA:① The positive rate of Titin-Ab and RyR-Ab in MG were 40.3% and 24.2%, and negative in NMG and NC groups, MG groups were significantly higher than those of NMG groups and NC groups(P <0.01); ② The highest percentage is in MGT , Titin-Ab was 82.3% and RyR-Ab was 76.5%, then inMG with thymic atrophy(MGA), respectively was 41.6% and 8.3%, in MG with thymic hyperplasia (MGH) , 0 and 16.6%; in MG with normal thymic(NTMG) ,22.2% and 0; ③There was a positive correlation between titer of Titin-Ab RyR-Ab and severity of muscle weakness(r=0. 562 and 0. 547, P<0.01); ④ The titer of the antibodies decreased significantly in sera of 10 MG patients with different thymic pathological patterns after therapy(P<0.01);⑤Comparing with CT scanning of thymus in diagnosis of MGT,Titin-Ab and RyR-Ab are lower in sensitivity, but higher in specificity (P <0.05). Western blot analysis showed that the positive bands of RyR-Ab were tested in 13 of 17 cases of MG with thymoma(82.3%), significantly higher than those of NTMG groups and NMG groups(P<0.01).Conclusion: ① Titin-Ab and RyR-Ab are associated with the pathogenesis of MG; ② Titin-Ab and RyR-Ab are mostly tested in MG,especially in MGT , so these antibodies can be taken as a specific marker for MGT; ③ In diagnosing MGT, Titin-Ab and RyR-Ab have higher specificity than CT scan, and the deficient of CT scan can solved by assaying these antibodies;④ There are correlation between Titin-Ab RyR-Ab and the severity of MG, therefore it is indicated that testing Titin-Ab and RyR-Ab is useful in evaluating curative effect and prognosis of MG; As a new way for diagnosing MGT, it has very important clinic significance.