辅助性T细胞及其细胞因子在重症肌无力中的作用

Effects of circulating T helper cells and related cytokines on myasthenia gravis

目的探讨辅助性T细胞及其相关细胞因子在全身型MG患者急性期发病中的作用。方法采用流式细胞术检测33例全身型MG患者和34例健康对照组外周血中Tfh细胞亚群CXCR5^+CD4^+T、CD45RO^+CXCR5^+CD4^+T、CD45RA^+CXCR5^+CD4^+T、ICOS^+CXCR5^+CD4^+T和PD-1^+CXCR5^+CD4^+T细胞占CD4^+T细胞的比例。采用流式液相多重蛋白定量(cell based assay,CBA)技术检测MG组及对照组血清中IL-17A、IFN-γ、IL-4、IL-21的含量。应用ELISA技术检测MG组及对照组血清中IL-22的含量。根据QMGs(the quantitative myasthenia gravis score,QMGs)对纳入研究的MG患者进行评分,QMGs反映了MG患者的病情严重程度。结果 MG组外周血中的循环Tfh细胞(ICOS^+CXCR5^+CD4^+T和PD-1^+CXCR5^+CD4^+T)较对照组增高(P=0.016,P<0.001),且PD-1^+CXCR5^+CD4^+T细胞与MG患者病情严重程度正相关(r=0.405,P=0.019)。MG组血清IL-21、IL-17A、IFN-γ的含量较对照组升高,有统计学意义(P=0.007,P=0.016,P=0.007);MG组血清IL-4的含量较对照组略有增多,IL-22含量较对照组略有减少,但均无统计学意义。MG组IL-4含量QMGs呈负相关,差异具有显著性(r=-0.393,P=0.024)。结论 MG急性期ICOS^+和PD-1^+的循环Tfh细胞可能促进MG发病;IL-21、IFN-γ、IL-17A同样可能促进MG发病;IL-4可能对MG有保护作用。

Objective In this study,We aimed to investigate the role of the T helper（ Th） cells and related cytokines in peripheral blood of generalized MG patients. Methods A total of 33 generalized MG patients and 34 age matched controls were enrolled in this study. Peripheral blood mononuclear cells（ PBMCs） were isolated using Ficoll-Paque density gradient centrifugation assay. The proportion of follicular helper T（ TFH） cells in PBMC were analyzed using flow-cytometry assay by determining the levels of cellular markers CD4,CXCR5,CD45 RO,CD45 RA and ICOS and PD-1. The levels of IFN-γ,IL-4,IL-17 and IL-21 in serum were anaylzed by Cytometric Bead Array. The serum IL-22 level were analyzed by ELISA. According to the quantitative myasthenia gravis score（ QMGs）,the patients who were included in the study were graded,and QMGs reflected the severity of the patient＇s condition. Results The frequency of circulating Tfh cells（ ICOS^＋Tfh and PD-I^＋Tfh） in PBMCs was higher than those in healthy subjects（ P = 0. 016,P〈0. 001） and PD-1^＋CXCR5^＋CD4^＋T cells are were correlated to the severity of MG patients（ r = 0. 405,P = 0. 019）. The levels of pro-inflammatory cytokines IFN-γ,IL-17 and IL-21 were elevated in the serum of MG patients（ P = 0. 007,P = 0. 016,P = 0. 007）,while there were no significant differences regarding the levels of IL-4 and IL-22 between MG patients and control subjects. The level of IL-4 in MG patients was negatively correlated to the severity of MG patients（ r =-0. 393,P = 0. 024）. Conclusion Our findings suggested that circulating TFH cells and IL-21,IFN-γ,IL-17A may promote the initiation and development of MG.IL-4 may be protective against MG.