过敏性紫癜患儿急性期Tfh细胞改变及意义初探

Alteration mechanism of T follicular helper cell in Henoch-Schonlien purpura

探讨滤泡辅助性T细胞(Tfh细胞)在儿童过敏性紫癜中的数量变化及其可能机制。过敏性紫癜(HSP)急性期患儿20例,采用流式细胞术检测外周血CD4+CXCR5+ICOS+T细胞(Tfh)的比例,采用荧光定量聚合酶链反应(real-time PCR)检测转录因子Bcl-6及其拮抗因子Blimp-1的mRNA表达,酶联免疫吸附试验检测IL-21、IL-4血浆浓度。HSP急性期患儿Tfh细胞比例明显高于正常对照组(2.9±1.0%vs 1.8±0.72%,P<0.05);Tfh细胞正性转录调节因子Bcl-6mRNA表达较正常对照组明显增高(P<0.05),负性调节因子Blimp-1mRNA表达降低(P<0.05);Tfh细胞相关细胞因子IL-21血浓度明显高于正常对照组(P<0.05),抑制Blimp-1表达的IL-4血浆浓度明显高于正常对照组(P<0.05)。Tfh细胞过度活化可能参与HSP免疫发病机制,Bcl-6/Blimp-1表达失衡,IL-21、IL-4细胞因子微环境改变可能与Tfh细胞异常活化有关。

To explore the alteration mechanism of T follicular helper（Tfh） cells in patients with Henoch-Schonlien purpura （HSP）, twenty children with HSP were enrolled in this study for evaluating of the proportion of CD4 ＋ CXCR5 ＋ ICOS＋ T cells （Tfh） in peripheral blood. Tfh ells were analyzed by flow cytometry. Real-time PCR was performed to detect the level of Tfh ceils＇ transcriptional factor （Bcl-6） and its inhibitor （Blimp-l）. The plasma levels of IL-21 and IL-4 were determined by ELISA. During the acute phase of HSP, the proportion of CD4＋ CXCR5＋ ICOS＋ T cells in the patients was significantly higher than that in the healthy controls（2.9±1.0% vs 1.8±0.72%, P〈0.05）. While the transcription levels of Bcl-6 were signifi- cantly elevated in the patients （P〈0.05）, those of Blimp-1 were found to be down-regulated （P〈0.05）. Plasma levels of IL- 21 and IL-4 were increased in the patients compared with healthy controls（P〈0.05）. The above findings suggest that over-ac- tivation of Tfh cells might be correlated with immune aberrance occurred in HSP. Dysregulation of Bcl-6/Blimp-1 and the al- tered microenvironment provided by IL-21 and IL-4 might be correlated with the abnormal activation of Tfh cells.