免疫性血小板减少症患者外周血中滤泡辅助性T细胞和IL-21的水平及临床意义

Detection of follicular helper T cells and interleukin-21 in peripheral blood of patients with immune thrombocytopenia and their clinical significance

目的探讨滤泡辅助性T细胞(Tfh细胞)和IL-21在免疫性血小板减少症(ITP)中的作用。方法采集15例ITP患者及20例健康对照者外周血,用流式细胞术检测外周血单个核细胞(PBMC)中CXCR5+CD4+Tfh细胞的百分率,ELISA法检测血清IL-21水平;用实时荧光定量PCR检测PBMC中IL-21 mRNA的表达。结果 ITP组PBMC中CXCR5+CD4+Tfh细胞比例(17.55±1.015)%显著高于健康人对照组(10.19±0.343)%,差异有统计学意义(t=7.657,P<0.01);ITP组血清中IL-21水平(100.7±3.71)pg/mL显著高于健康人对照组(64.6±0.81)pg/mL,差异有统计学意义(t=10.84,P<0.01),且两者之间存在明显相关性(r=0.689 3,P<0.01)。ITP患者IL-21 mRNA的相对表达量4.319±0.767明显高于健康人对照组1.125±0.052,差异有统计学意义(t=4.813,P<0.01)。结论 ITP患者外周血Tfh细胞比例、IL-21水平及IL-21 mRNA表达均增高,可能在ITP的发病机制中发挥重要作用。

Objective To investigate the role of follicular helper T （Tfh） cells and interieukin-21 （IL-21） in patients with immune thrombocytopenia （ITP）. Methods The percentage of circulating CXCR5＋ CD4＋ Tfh cells in peripheral blood mononuclear cells （PBMC） and the level of IL-21 in serum from 15 patients with ITP and 20 healthy controls （HC） were determined by flow cytometry and ELISA, respectively. The expression of IL-21 mRNA in PBMCs was detected by real-time PCR. Results The percentage of circu- lating CXCR5＋ CD4＋ Tfh cells [ （ 17.55± 1. 015 ） % ] and the level of serum IL-21 [ （ 100.7 ±3.71 ） pg/mL] in patients with ITP were significantly higher than those in HC＋ （ 10.19± 0. 343 ） %, t = 7. 657, P 〈 0.01 ; （64.6 ± 0.81 ） pg/mL, t = 10.84, P 〈0. 01 ]. Moreover, there was a positive correlation between the percentage of CXCR5＋ CD4＋ Tfh cells and the level of serum IL-21 in ITP patients （ r = 0. 6893, P 〈 0.01 ）. In addition, the expression level of IL-21 mRNA in ITP patients （4.319 ±0.767） was also sig- nificantly higher than that in HC （ l. 125 ± 0. 052） （ t = 4.813, P 〈 0.01 ）. Conclusion The percentage of circulating Tfh cells and the expression of IL-21 mRNA in PBMCs and serum IL-21 level in ITP patients increase, indicating that Tfh ceUs and IL-21 may play an important role in the pathogenesis of ITP.