脓毒症患儿CD4^＋CD25^＋调节性T细胞的变化

Changes of the CD4^＋ CD25^ ＋ regulatory T cells in infant with sepsis

目的 观察不同免疫状态下脓毒症婴幼儿外周血CD4^＋CD25^＋Foxp3^high出调节性T细胞（Treg细胞）及相关分子的变化，探讨婴幼儿脓毒症免疫功能紊乱的可能机制。方法分别收集2007年5月至2007年11月深圳市儿童医院重症监护室收治的婴幼儿脓毒症36例血液标本，另选16例健康同龄儿童作为正常对照进行前瞻性研究；排除既往患有自身免疫性疾病、免疫缺陷病、遗传代谢病及肿瘤的患儿，排除近6个月曾使用影响免疫功能的药物。本研究获得深圳市儿童医院伦理委员会的同意。以外周血CD14^＋单核细胞HLA—DR表达〉30％或〈30％为闽值，将患儿分为免疫激活组（DR-H组）和免疫抑制组（DR-L组），用流式细胞术检测CD14^＋单核细胞HLA-DR表达率，CD4^＋CD25^＋Foxp3^high Treg细胞比例；实时荧光定量PCR（Realtime—PCR）检测CD4^＋T细胞Foxp3、CTLA-4、G1TR、IL-10mRNA表达。统计方法采用单因素方差分析，P〈0．05为差异具有统计学意义。结果急性期DR．L组CD4^＋CD25^＋Foxp3^high Treg细胞比例明显高于对照组及DR—H组（P〈0．05）。DR-L组Foxp3、CTLA-4、IL-10等相关分子基因表达高于对照组及DR—H组（P〈0．05），DR-L组G1TR基因表达高于DR-H组。结论CD4^＋CD25^＋Foxp3^high Treg细胞数量异常增加可能与婴幼儿脓毒症免疫抑制状态有关。

Objective To study the change of CD4^＋ CD25^＋ Foxp3^high regulatory T cells （Treg cells） and the molecules associated with Treg cells in different immune status in infant with sepsis, and to further clarity the pathogenesis of disturbed immune function in infant with sepsis. Method Totally 36 sepsis infants admitted in Intensive Care Unit of Shenzhen Children＇s Hospital from May 2007 to November 2007 and 16 age-matched healthy infants were collected for prospective study, after excluding autoimmune disease, immunodeficiency, inherited metabolic disorders, tumor, and drug-treatment that could affect immune function during lately 6 months. The study was approved by Ethics Committee of Shenzhen Children＇ s Hospital. The 36 infants with sepsis were divided into two groups according to expression levels of HLA-DR in CD14-positive cells： DR-H group was defined as patients with HLA-DR 〉 30%, while DR-L group was defined as patients with HLA-DR 〈 30%. Expression levels of HLADR in CD14-positive cells and the proportion of Treg cells were analyzed by flow cytometry. Real-time PCR were used to evaluate the mRNA levels of Foxp3, CTLA-4, GITR, and IL-10 in CD4-positive cells. Statistical analysis was performed by one-way Anova. There was statistical difference with P 〈 0.05. Results The proportion of Treg ceils in DR-L group was found to be significantly higher than that in healthy control or DR-H group （ P 〈 0.05）. Compared with healthy control group or DR-H group, transcriptional levels of Foxp3, CTLA-4 and IL-10 were significantly increased in DR-L group （P 〈 0.05）. The levels of GITR mRNA in DR-L group were detected to be higher than those in DR-H group （ P 〈 0.05）. Conclusions Aberrant increased proportion of Treg cells may be associated with suppressed immune status in infant with sepsis.