CD4+CXCR5+Tfh细胞比例及其调控因素变化对哮喘患儿的影响

Alterations of CD4+CXCR5+Tfh cells and its transcription regulatory factors in children with asthma

摘要:

目的 探讨哮喘患儿外周血滤泡样辅助性T细胞(CD4⁺CXCR5⁺Tfh细胞)比例及其转录调控因子BCL-6、BLIMP-1的表达变化.方法 依据病情将64例哮喘患儿分为哮喘急性期组(n=36)和哮喘缓解期组(n=28),另选取同期在我院行健康体检儿童25例为对照组.流式细胞术检测各组外周血CD4⁺CXCR5⁺Tfh细胞数量;实时荧光定量 PCR仪检测各组转录调控因子BCL-6、BLIMP-1 mRNA表达;双抗夹心ELISA法检测血浆总IgE、IL-2、IL-6 、IL-21浓度水平.结果 哮喘急性期组患儿CD4⁺CXCR5⁺Tfh细胞比例明显高于对照组及哮喘缓解期组(P<0.05);哮喘急性期组患儿BCL-6 mRNA表达水平显著高于对照组及哮喘缓解期组(P<0.05),而BLIMP-1 mRNA表达水平明显低于对照组及哮喘缓解期组(P<0.05);哮喘急性期组患儿血浆IL-6水平显著高于对照组(P<0.05),血浆IL-21和总IgE水平显著高于对照组和哮喘缓解期组(P<0.05),血浆IL-2水平明显低于对照组和哮喘缓解期组(P<0.05);血浆IL-21和IL-6水平与CD4⁺CXCR5⁺Tfh细胞数量呈正相关(分别r=0.76、0.46,均P<0.05),与IL-2水平呈负相关(r=-0.68, P<0.05).结论 外周血CD4⁺CXCR5⁺Tfh细胞比例增高可能参与了儿童哮喘的急性发病过程,转录调控因子BCL-6 及BLIMP-1 mRNA的异常表达,以及局部微环境中总IgE和细胞因子IL-2、IL-6、IL-21的浓度改变可能与哮喘患儿CD4⁺CXCR5⁺Tfh细胞分化异常有关.

Abstract:

Objective To study the alterations of follicular T helper cells (CD4⁺CXCR5⁺Tfh cells, Tfh) on circulating T lymphocytes in children with asthma, and to study the expression of transcription regulatory factors BCL-6 and BLIMP-1 mRNA. Methods Sixty-four children with asthma and 25 healthy controls were enrolled in this study. On the basis of the disease, the children with asthma were classified into acute phase group (n=36) and remission phase group (n=28). The flow cytometry was used to detect the proportion of CD4⁺CXCR5⁺Tfh cells on CD4⁺T lymphocytes. Real-time PCR was performed to detect the levels of BCL-6 mRNA and BLIMP-1 mRNA. The double-antibody Sandwich ELISA was used to detect plasma concentrations of total IgE, IL-2, IL-6 and IL-21. Results The proportion of CD4⁺CXCR5⁺Tfh cells was significantly higher in the acute group than in the control group and the remission group (P<0.05). Transcription levels of BCL-6 mRNA were significantly higher, while the inhibitory factors BLIMP-1 mRNA was significantly lower in the acute group than in the remission group and control group (P<0.05). The plasma concentration of IL-6 in the acute group increased significantly compared with the control group (P<0.05). Plasma concentrations of total IgE and IL-21 increased significantly, in contrast, plasma IL-2 concentration decreased significantly in the acute group, compared with the control group and the remission group (P<0.05). Correlation analysis showed that both IL-21 and IL-6 concentrations were positively correlated with the proportion of CD4⁺CXCR5⁺Tfh cells (r=0.76, r=0.46 respectively; P<0.05), while IL-2 level was negatively correlated with the proportion of Tfh cells (r=-0.68, P<0.05). Conclusions The abnormal proportion of CD4⁺CXCR5⁺Tfh cells might be involved in the immunological pathogenesis of acute asthma in children. The increased expression of BCL-6 mRNA and decreased expression of BLIMP-1 mRNA as well as the alterations of plasma total IgE, cytokines IL-2, IL-6 and IL-21 in microenvironment might be account for the increased proportion of CD4⁺CXCR5⁺Tfh cells in children with acute asthma.