The Relationship Between Different Antibodies And The Post-thymectomy Clinical Outcome Of Generalized Myasthenia Gravis

Objective Myasthenia gravis(MG) patients would be divided into acetylcholine receptor antibody(Ach R-Ab) positive MG, muscle-specific tyrosine kinase antibody(Mu SK- Ab) positive MG and Ach R-Ab / Mu SK- Ab double-negative MG according to serum antibody types, the purpose of our study was to analyze the main clinical features in the three groups, To compare the post-thymectomy clinical outcome of thymectomy generalized myasthenia gravis(MG) with different antibodies. The primary endpoint was to assess differences in the rate of complete stable remission(CSR) in patients in the three groups.Methods The acetylcholine receptor and muscle specific receptor tyrosine kinase antibodies were detected in the sera of 130 g MG patients who were retrospectively reviewed had received video—assisted thoracoscopic thymectomy in Thoracic Surgery, Enzyme-linked immunosorbent assay(ELISA) were applied.According to the type of the serum antibodies,the patients were divided into ACh R-Ab-positive group, ACh R-Ab / Mu SK-Ab double negative group and Mu SK- Ab-positive group.Results There were 81 patients in the AchR-Ab positive group, 43 patients in the ACh R-Ab / Mu SK-Ab double negative group,and 6 patients in the Mu SK- Ab-positive group. there was no significant difference among the three groups regarding Sex,age at onset an,disease duration and thymus pathology.Mu SK-Ab positive patients with predominantly bulbar paralysis,the proportion is higer than ACh R-Ab-positive group and ACh R-Ab / Mu SK-Ab double negative group [(x2=6.945, P=0.023 å'Œ X2=6.577, P=0.026)];3/6 of Mu SK-Ab positive patients were classified as MGFA III to V, the proportion is higer than the other two groups [(x2=6.232, p=0.041 å'Œ x2=11.81, p=0.01) ].Until the dead line of follow — up time of sep. 2014,one Case in ACh R-Ab-positive group was lost,two Cases in ACh R- and Mu SK-negative group were lost,Follow-up time was 15 to 84 months,mean(45.8 ± 20.2)months. The complete stable remission rate(CSR) in ACh R-Ab-positive group was 48.8%,in the ACh R- and Mu SK-negative group the vaule was 2 6. 8 %, in the Mu SK- Ab-positive group the vaule was 1 6. 7 %, the CSR in the ACh R-Ab-positive group is higer than the ACh R- Ab /Mu SK-Ab double negative group [(X2=5.372,P=0.02)], And the effective rates about different age, gender, pathological foundings and MGFA classification have no significance(P>0.05). the csr in who disease duraton ≦12 months is higer than that > 12 months [(x2=6.402, p= 0.011)].Conclusion Long-term post-thymectomy clinical outcome was better in patients with anti-ACh R antibodies than in those the ACh R-Ab and Mu SK-Ab double negative group, the CSR in whose disease duraton ≦12 months is higer than that > 12 months,there was no different in overall effectiveness.