喘息样支气管炎患儿肠道微生态变化与免疫耐受关系的研究

The relationship between intestinal microflora and immune tolerance in infants with asthmatic bronchitis

目的观察喘息样支气管炎患儿肠道菌群变化,探讨肠菌群变化与免疫耐受间关系。方法采用16S rDNA荧光定量PCR法、流式细胞术和ELISA方法对47例喘息样支气管炎患儿、40例急性支气管炎患儿和30例健康儿童进行粪便双歧杆菌与大肠埃希菌的定量检测,外周血单个核细胞CD4+CD25+T细胞(Treg)和血浆细胞因子TGF-β1的测定。结果喘息样支气管炎、急性支气管炎患儿粪便中双歧杆菌数量和双歧杆菌/大肠埃希菌比值(B/E值)较健康对照组减少(P<0.05),且喘息样支气管炎患儿粪便双歧杆菌数量和B/E值均低于急性支气管炎患儿(P<0.05)。喘息样支气管炎患儿的外周血Treg百分数、血浆TGF-β1浓度均低于急性支气管炎患儿和健康对照组(P均<0.05);且外周血Treg百分数和血浆TGF-β1水平与肠道B/E值呈直线正相关关系。结论喘息样支气管患儿发病初期即发生肠道菌群紊乱,肠道有益菌数量下降,且诱导免疫耐受失败。肠道菌群紊乱与免疫功能失衡间存在相互影响与制约关系,免疫耐受被打破贯穿疾病的整个病理过程。

Objective To observe the alteration of intestinal flora in asthmatic bronchitis, and explore the relationship of intestinal flora and immune tolerance. Methods Forty-seven children with asthmatic bronchitis, forty children with acute bronchitis, and thirty healthy children as control group were enrolled into this study. 16S rDNA fluorescent quantitative PCR was applied in determine the con- tent of Bifidobacteria and Escherichia coli in feaces. Flow cytometrie （FCM） analysis was performed to detect the percentage of CD4 ~ CD25 ~ T cell （Treg）. Enzyme linked immunosorbent assay （ELISA） was used to detect the levels of TGF-[31 in plasma. Results The quantities of intestinal bifidobacteria and B/E ratio in asthmatic bronchitis and acute bronchitis were significantly lower than in healthy children （ P 〈 0.05 ） ; and the quantity of intestinal bifidobacteria and B/E ratio in asthmatic bronchitis were lower than in acute bronchitis （ P 〈 O. 05）. The percentage of CD4 ＋ CD25 ＋ T cell （Treg） and the concentrations of plasma TGF-131 in asthmatic bronchitis were lower than in acute bronchitis and healthy children （ P 〈 0.05 ）. There was a positively correlation between B/E ratio and Treg percentage, and between B/E ratio and TGF-131. Conclusion Intestinal flora were disordered and failed to induce immune tolerance in children with asthmatic bronchitis in the early stage of the disease. There is an interaction and mutual restraint between intestinal dysbacterosis and im- mune imbalance. Immune tolerance is broken throughout the entire nathological Process of asthmatic bronchitis.