β_2-肾上腺素能受体基因多态性与儿童哮喘的关系

Relationship between genetic polymorphisms of β_2-adrenergic receptor and childhood asthma

目的从分子水平探讨喘息性支气管炎和小儿支气管哮喘的相关性。方法采用PCR-限制性核酸内切酶法对β2-肾上腺素能受体(β2-AR)基因多态性进行分析,用ELISA法检测血浆总IgE,对217例小儿哮喘,119例喘支和50例健康儿童进行比较分析。结果①三组β2-AR基因16位点多态性分布差异无统计学意义(P>0.05);②β2-AR基因27位点多态性中谷氨酸/谷氨酸基因型频率在哮喘组明显低于对照组(P<0.05),喘支组与对照组比较差异无统计学意义,与哮喘组比较差异也无统计学意义(P>0.05);哮喘组谷氨酸等位基因频率明显低于对照组,谷氨酰胺等位基因频率高于对照组(P<0.05)。③β2-AR基因16位点各基因型间的血清总IgE水平差异无统计学意义(P>0.05);哮喘和喘支组27位点中谷氨酰胺纯合子基因型的总IgE水平明显高于杂合子及谷氨酸纯合子(P<0.05),谷氨酸纯合子和杂合子基因型的IgE水平差异无统计学意义。结论在β2-AR基因27位点喘息性支气管炎与支气管哮喘有相关性,尤其是具有谷氨酰胺/谷氨酰胺基因型且血浆总IgE增高的喘支与哮喘的关系更为密切。

Objectives To explore the correlation between asthmatic bronchitis and asthma at molecular level. Methods The polymorphisms of β2-adrenergic receptors （β2-AR） in 217 children with asthma, 119 children with asthmatic bronchitis and 50 healthy children were detected with PCR restriction fragment analysis,and their plasma concentration of total IgE were determined by enzyme linked immunosorbent assay. Results （ 1 ） There was no significant difference in the frequencies of genotypes and alleles of β2-AR 16 loci among the three groups（P 〉 0.05）. （2） The frequency of Glu/Glu genotype of β2-AR 27 loci in the asthmatic group was significantly lower than that in the control group （P 〈 0.05）. There was no significant differences between the asthmatic bronchitis group and the control group or the asthmatic group in Glu/ Glu frequency（P 〉 0.05）. The frequency of Glu27 allele in the asthmatic group was significantly lower than that in the control group,while the frequency of Gln27 allele in the two groups was on the contrary（P 〈 0.05）. （3） There were no significant differences in total plasma IgE among the three genotypes of β2-AR 16 loci. The total IgE level in Gln/Gln genotype was significantly higher than that in Glu/Glu and Gln/Glu of the asthma group and the asthmatic bronchitis group （P 〈 0.05 ）, however no differences were observed between Glu/Glu and Gln/Glu. Condnsions Asthmatic bronchitis is correlated with asthma in genetic polymorphism of β2-AR 27 locus. Strong correlation with earlier asthma can be considered when the asthmatic bronchitis with both Gln/Gln genotype of β2-AR 27 loci and high total plasma IgE. The polymorphisms of the β2-adrenergic receptors can help to make earlier diagnosis for childhood asthma,which also provide evidences at molecular level for the correlation study between asthmatic bronchitis and asthma.