哮喘患儿外周血炎症因子及肺功能水平与TLR4基因多态性的相关性研究

The correlation between peripheral blood inflammatory factors,lung function levels,and TLR4 gene polymorphisms in children with asthma

目的分析儿童哮喘患者外周血炎症因子及肺功能水平与Toll样受体4(Toll-like receptor 4,TLR4)基因多态性的相关性。方法收集近3年收治急性发作期哮喘患儿172例作为实验组,并根据哮喘患儿发病的严重程度将哮喘分为轻度、中度、重度和危重级,选取同期健康体检儿童136例作为对照组,测定各组受试者肺功能指标第1秒用力呼气容积(FEV1)占用力肺活量(FVC)百分比(FEV1/FVC%)和呼出气一氧化氮(FeNO)水平比,采集研究对象的外周静脉血,应用ELISA法检测白细胞介素4(interleukin-4,IL-4)、γ干扰素(interferon-γ,IFN-γ)表达水平,采用血球计数仪检测外周血嗜酸性粒细胞百分率(Eos),利用化学发光发检测血清总IgE,聚合酶链式反应-限制性内切酶片段长度多态性(PCR-RELP)技术检测TLR4基因Asp299Gly(A/G)和Thr399Ile(C/T)位点单核苷酸多态性,分析以上基因多态性与儿童哮喘的相关性。结果哮喘患儿外周血中IL-4、Eos、IgE及FeNO水平比显著高于对照组,IFN-γ和肺功能指标FEV1/FVC%的水平显著低于对照组(均P<0.05)。实验组及对照组TLR4基因Asp299Gly基因型和等位基因分布相比,差异无统计学意义(P>0.05),而Thr399Ile基因型和等位基因分布差异有统计学意义(P<0.05),其中实验组T等位基因分布频率显著高于对照组(P<0.05)。TLR4基因Thr399Ile多态性与哮喘患儿外周血Eos、IgE的水平、肺功能指标FEV1/FVC%无相关性(P>0.05),但携带Thr399Ile TT基因型哮喘患儿的IL-4和FeNO水平比高于CC和CT基因型,IFN-γ的水平低于CC和CT基因型(P<0.05)。有序logistic回归分析显示携带Thr399Ile TT基因型哮喘患儿比携带CC和TC基因型者哮喘发病程度更严重,二元logistic回归分析结果显示TLR4基因Thr399Ile多态性与儿童哮喘具有相关性。结论TLR4 SNPs与哮喘患儿体内免疫球蛋白IgE、Eos、肺功能指标FEV1/FVC(%)水平无关,但与哮喘严重程度及IL-4、IFN-γ、FeNO水平比相关,TLR4、IL-4、IFN-γ参与儿童哮喘的过程,并可能是哮喘由轻症进展成重症的关键因子,同时TLR4基因Thr399Ile位点多态性与儿童哮喘存在较大关联。

Objective To investigate the correlations between Toll-like receptor 4(TLR4)gene polymorphism and inflammatory factors and lung function in children with asthma.Methods A total of 172 children with acute asthma attacks treated over the past three years were selected as the experimental group.Based on the severity of asthma attacks,the children were categorized into mild,moderate,severe,and critical levels.A control group consisting of 136 healthy children who underwent routine health examinations during the same period was selected.The lung function parameters(FEV1/FVC%)and fractional exhaled nitric oxide(FeNO)were measured in all subjects.Peripheral venous blood samples were collected for ELISA analysis of interleukin-4(IL-4)and interferon-gamma(IFN-γ)expression levels.Additionally,eosinophil percentage(Eos)was determined using a hematology analyzer,total IgE was measured using a chemiluminescence immunoassay,and TLR4 gene polymorphisms(Asp299Gly and Thr399Ile)were detected using polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)analysis.The correlations between these gene polymorphisms and childhood asthma were analyzed.Results Levels of IL-4,Eos,IgE,and FeNO in the peripheral blood of children with asthma were significantly higher in the experimental group than in the control group,while IFN-γlevels and FEV1/FVC%were significantly lower in the experimental group.There were no significant differences in TLR4 gene Asp299Gly genotypes or allele distributions between the experimental and control groups(P>0.05).However,there were significant differences in Thr399Ile genotypes and allele distributions(P<0.05).The frequency of the T allele distribution was significantly higher in the experimental group.The TLR4 gene Thr399Ile polymorphism was not correlated with peripheral blood Eos,IgE levels,or lung function indicator FEV1/FVC%in children with asthma.However,children with the Thr399Ile TT genotype exhibited higher levels of IL-4 and FeNO compared to those with the CC and CT genotypes,while IFN-γlevels were lower.Logistic regression analysis showed that children with the Thr399Ile TT genotype had more severe asthma than those with the CC and TC genotypes.Binary logistic regression analysis revealed a correlation between TLR4 gene Thr399Ile polymorphism and childhood asthma severity.Conclusion TLR4 gene single nucleotide polymorphisms are not associated with IgE,Eos,or lung function indicator FEV1/FVC%levels in children with asthma.However,they are associated with asthma severity and IL-4,IFN-γ,and FeNO levels.TLR4 and IL-4,IFN-γmay play a role in the progression of childhood asthma and could be key factors in the transition from mild to severe asthma.The TLR4 gene Thr399Ile polymorphism is significantly associated with childhood asthma.