The role of FoxP3~+CD4~+CD25~+ T cells in the pathogenesis of myasthenia gravis

Objective To identify the expression defects of CD4+CD25+ regulatory T cells(CD4+CD25+ Tregs)in peripheral blood from myasthenia gravis(MG)patients at the cellular and molecular levels,with special focus on the effect of thymectomy on CD4+CD25+ Tregs,and to investigate the relationship between the abnormalities of CD4+CD25+ Tregs subset and the onset of MG.Methods Peripheral blood samples were obtained from 21 MG patients(11 patients have been thymectomized)and 20 healthy controls(HCs),flow cytometry was used to analyze the number of CD4+CD25+ Tregs and FoxP3+CD4+CD25+ Tregs and real-time fluorescent quantitative polymerase chain reaction(RT-FQ-PCR)was used to determine the FoxP3 mRNA level of CD4+CD25+ Tregs.Results There were no differences in the percentages of CD4+CD25+ Tregs among CD4+ T cells between MG patients and HCs(P0.05),the FoxP3-positive CD4+CD25+ Tregs(FoxP3+CD4+CD25+ Tregs)and the mRNA expression of FoxP3 were significantly different in CD4+CD25+ Tregs of MG patients as compared to HCs(P0.05);the frequencies of CD4+CD25+ Tregs and the expression of FoxP3 were similar in MG patients irrespective of treatment with thymectomy(P0.05).Conclusions The number of the CD4+CD25+ Tregs is normal in MG patients,but the expression of their surface molecule Foxp3 is decreased.The abnormal finding on the CD4+CD25+ Tregs subset could contribute to further elucidate the immunologic pathogenesis in MG.