过敏性紫癜患儿外周血单核细胞TLR2、TLR4、TLR6及与Treg相关细胞因子的表达

Expression of Toll-like receptor 2, Toll-like receptor 4 and Toll-like receptor 6 in peripheral blood mononuclear cells and their relationship with Treg immune response in children with Henoch-Schonlein purpura

背景:Toll样受体介导的信号通路转导及调节性T细胞异常活化在过敏性紫癜发病中的作用不清楚。目的:研究Toll样受体TLR2、TLR4、TLR6在过敏性紫癜患儿外周血单核细胞的表达及调节性T细胞(Treg)的免疫应答,探讨TLR及Treg活化在敏性紫癜发病机制中的作用。方法:选择处于过敏性紫癜急性期的患儿42例为观察对象,另选取15名门诊健康查体儿童为正常对照组。采用流式细胞术检测外周血单核细胞的TLR2、TLR4、TLR6的蛋白表达量;应用反转录-聚合酶链反应(RT-PCR)及实时荧光定量PCR检测外周血单核细胞TLR信号途径分子MyD88 mRNA的基因相对表达量;ELISA法测Treg细胞分泌的转化生长因子β、白细胞介素10的血浆水平;两组间比较采用独立样本t或t’检验,相关性分析采用Pearson相关检验。结果与结论:过敏性紫癜患儿外周血单核细胞的TLR2、TLR4、TLR6蛋白的表达及MyD88 mRNA基因的相对表达量均显著高于对照组(P<0.01);过敏性紫癜患儿血浆中转化生长因子β、白细胞介素10均高于对照组(P<0.05);过敏性紫癜患儿TLR2、TLR4、TLR6的蛋白表达量与Myd88 mRNA的基因相对表达量呈正相关(P<0.01),与血浆白细胞介素10、转化生长因子β水平无明显相关(P>0.05)。提示TLR2、TLR4、TLR6活化后可能通过MyD88依赖的途径参与敏性紫癜的发病,而过敏性紫癜急性期Treg代偿性活化可能为机体的保护性免疫应答。

BACKGROUND： The influence of Toll-like receptor 2 （TLR2）, Toll-like receptor 4 （TLR4）, Toll-like receptor 6 （TLR6） signal transduction pathway and active Treg in children with Henoch-Schonlein purpure has been unknown. OBJECTIVE： To investigate the expression of TLR2, TLR4 and TLR6 in peripheral blood mononuclear cells and Treg immune response in patients with Henoch-Schonlein purpura, and to explore the role of TLR2, TLR4, TLR6 and Treg activation in the pathogenesis of Henoch-Schonlein purpura.METHODS： Forty-two hospitalized children with Henoch-Schonlein purpura were enrolled in this study. Another 15 healthy children were selected as controls. TLR2, TLR4 and TLR6 at protein level in peripheral blood mononuclear cells were detected by flow cytometey; reverse-transcription PCR and real-time PCR were used to evaluate the level of MyD88; the levels of transforming growth factor-β and interleukin-10 were measured by enzyme-linked immunosorbent assay, t-test or t＇-test was used to compare the levels of these genes and proteins. Pearson＇s correlation test was done for correlation analysis. RESULTS AND CONCLUSION： Compared with the control group, the protein levels of TLR2, TLR4, TLR6 and the relative expression level of MyD88 mRNA were significantly up-regulated （P 〈 0.01 ）. The serum levels of transforming growth factor-~ and intedeukin-10 were higher in the Henoch-Schonlein purpura children than the healthy children （P 〈 0.05）. There was a significant correlation between the protein levels of TLR2, TLR4, TLR6 and mRNA level of MyD88 （P 〈 0.01）, but no relationship was found between TLRs and intedeukin-10, transforming growth＇factor-β （P 〉 0.05）. The excessive activation of TLR2, TLR4, TLR6 may be involved in the process of Henoch-Schonlein purpure via MyD88-dependent pathway, and the compensatory activation of Treg may participate in protective immunity.