反复呼吸道感染患儿红细胞CR1数量基因多态性及其红细胞免疫功能

Relationship between the erythrocyte CR1 genomic density polymorphism and erythrocyte immune function in children with recurrent respiratory tract infections

目的通过研究红细胞补体受体1(CR1)数量基因多态性与红细胞免疫功能的相关性,探讨反复呼吸道感染(RRTI)患儿的遗传易感因素。方法采用红细胞C3b受体花环率和红细胞免疫复合物花环率,并利用限制性内切酶HindⅢ,聚合酶链反应(PCR)测定38例RRTI患儿(病例组)和56例正常儿童(对照组)的红细胞CR1活性与CR1数量基因多态性,并进行比较。结果病例组中红细胞C3b受体花环率明显低于正常对照组,差异有显著性(P<0.01),而红细胞免疫复合物花环率略低于正常对照组,差异无显著性(P>0.05),且CR1基因HH、HL和LL基因型分布频率分别为34.2%、55.3%和10.5%,而对照组中HH、HL和LL基因型分布频率分别为75%、21.4%和3.6%。两组CR1基因型的分布频率差异有显著性(P<0.01)。病例组中HL和LL基因型占优势(OR=5.77)。两组CR1基因等位基因的分布频率差异也有显著性(P<0.01),病例组中L等位基因分布频率高于对照组。结论反复呼吸道感染患儿CR1数量基因多态性与红细胞免疫功能有相关性,提示CR1基因HindⅢ酶切位点多态性可能在决定个体反复呼吸道感染遗传易感性方面有重要作用。

Objective To explore the hereditary susceptibility of children to recurrent respiratory tract infections （RRTI） through .studying the association between CR1 genomic density polymorphism and erythrncyte immune function. Methods Subjects were selected from Kunming city and every subject was of Han ethnic group. The subjects were composed of two groups： the patient group consisted of 38 children with RRTI; the control group was composed of 56 normal children. The rates of RBC-C3bRR and the rates of RBC-ICR were detected by GuoFeng＇s method. The CR1 activity and genomic density polymorphism of erythrocyte from the two groups were detected by Hind Ⅲ restriction enzyme digestion, polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP）, DNA sequence analysis, and genetic analysis methods. Results The rates of RBC-C3bRR were significant lower in RRTI than in nonnal children （P 〈 0.01）. There was no significant difference of RBC-ICR rates between the two groups （ P 〉 0.05）. Frequencies of HH, HL, and LL genotypes were 34.2%, 55.3%, and 10.5% in the RRTI group, and were 75%, 21.4%, and 3.6% in the control group, respectively. A significant difference was found in the distribution frequency of CR1 genotype between the two groups （ P 〈 0.01 ）. HL and LL genotypes in the patient group were more common than those in control group （OR = 5.77）, indicating that HL and LL genotype may be significantly associated with RRTI. Moreover, CR1 allele frequencies of subjects from the two groups also showed significant difference （ P 〈 0.01）. L allele freqiemcu in patient group was higher than that in control group. Conclusion There is a close association between CR1 gencmic density polymorphism and RRTI. The results suggest that CR1 gene polymorphism may play an important role in determining susceptibility to RRTI.