反复呼吸道感染儿童血浆MBL水平及基因突变特征

SERUM MANNOSE-BINDING LECTIN LEVEL AND CHARACTERISTICS OF GENE MUTATION IN CHILDREN WITH REPEATED RESPIRATORY TRACT INFECTION

目的探讨血浆甘露聚糖结合凝集素(MBL)水平及基因多态性与儿童反复呼吸道感染(RRTI)的关系。方法选择110例RRTI儿童及111例健康儿童(均为汉族)为研究对象。应用酶联免疫吸附试验(ELISA)方法检测其血浆MBL水平,聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测MBL基因第一外显子54密码子、57密码子基因型和多态性。结果 RRTI儿童血浆MBL水平显著低于健康儿童组(t=7.19,P<0.01);各年龄段RRTI儿童血浆MBL水平均明显低于同年龄段健康儿童组(t=2.15～3.55,P<0.05、0.01),但RRTI儿童各年龄段间比较差异无显著性(P>0.05)。RRTI组MBL水平低下者检出率(23%)显著高于健康儿童组(6%)(χ2=9.12,P<0.01),MBL基因第一外显子54密码子基因型GGC/GGC、GGC/GAC、GAC/GAC分别对应高、中及低血清MBL水平。RRTI组MBL基因第一外显子54密码子等位基因GAC及GGC/GAC型突变杂合子频率显著高于健康儿童组(χ2=4.47～5.64,P<0.05)。两组均未检出57密码子突变个体。结论 MBL缺陷是RRTI的重要原因,与低MBL水平相关的MBL基因第一外显子54密码子等位基因GAC是儿童RRTI的危险因素。

Objective To investigate the relationship between the serum mannose-binding lectin（MBL） levels,gene polymorphisms and repeated respiratory tract infection（RRTI） in children. Methods The present study objects included 110 children with RRTI and 111 healthy children,all were Han people.The serum MBL levels were detected by enzyme-linked immune-sorbent assay（ELISA）,and the genotype,polymorphisms of code 54 and code 57 in the first exon of MBL gene were detected by the restriction fragment length polymorphism polymerase chain-reaction（PCR-RFLP）. Results The levels of serum MBL in children with RRTI,of various age groups,were significantly lower than that in the control group（t=7.19,P0.01）,but the difference of that among different age groups in RRTI children was not significant（P0.05）.In RRTI,the detection rate of structure gene in which with low MBL was higher than that of the control,being 23% versus 6%（χ2=9.12,P0.01）.The MBL structure gene code 54 genotypes GGC/GGC,GGC/GAC,and GAC/GAC corresponded to high,medium,and low serum MBL levels,respectively.The frequency of allele GAC and mutant heterozygous GGC/GAC at codon 54 in,the sick children was significantly higher than that in the control（χ2=4.47-5.64,P0.05）.Mutant code 57 was not detected in both groups. ConclusionMBL defect is an important reason of RRTI,and low MBL-related allele GAC on the code 54 is the risk factor of the disease in children.