Clinical Studies Of Titin Antibody And Ryanodine Receptor Antibody In Sera Of Myasthenia Gravis Patients

Objective:To investigate the clinical significance of serum Titin antibody and Ryanodine receptor(RyR) antibody in the diagnosis of myasthenia gravis(MG)., especially in myasthenia gravis with thymoma (MGT) and late-onset MG.Methods:We dectected Titin antibody and RyR antibody with enzyme-linked immunosorbent assay(ELISA) in61cases of MG group(including24cases of thymoma,6cases of thymic hyperplasia,31cases of normal thymus)and35cases of normal control group.Results:①The positive rates of Titin antibody and RyR antibody were62.3%and49.2%in MG group, while those in control group were11.4%and8.6%. The positive rates of both antibodies in MG group were significantly higher than those in control group. Significant differences of two antibodies positive rates in MG and control groups were observed(P<0.05).②Significant difference of the positive rates of Titin antibody in MGT group (83.3%) and non-thymoma MG group (48.6%) was observed (P＜0.05). There is no significant difference of RyR antibody positive rates in MGT group (58.3%) and non-thymoma MG group (43.2%)(P>0.05).③The higher positive rates of Titin antibody(80.0%) and RyR antibody(63.3%) were observed in late-onset MG group, which was significantly higher than the early-onset MG group (45.2%for Titin antibody and35.5%for RyR antibody). There were significant differences of both antibodies’positive rates between late-onset MG group and early-onset MG group(P<0.05).④In MG group, the level of Titin antibody and RyR antibody antibody was positively correlated to the severity of muscle weakness(r=0.520and0.487, P <0.001).Conclusions:The Titin antibody and/or RyR antibody test help to the diagnose of MG In the patients with late-onset MG, Titin antibody and RyR antibody showed a high positive rate. In the patients with MGT, the positive rate of Titin antibody was also high. The levels of Titin antibody and RyR antibody in patients with MG were positively correlated with the severity of muscle weakness,which can help evaluate the patient’s condition and prognosis.