目的 研究IL-4基因启动子区－589位点和－33位点单核苷酸多态性与呼吸道合胞病毒（RSV）毛细支气管炎易感性及病情严重度的关系，探讨遗传机制的差异对RSV感染发生和预后的影响。方法 采用MGB-Taq Man探针法对218例RSV毛细支气管炎患儿（RSV毛细支气管炎组）和303例健康儿童（正常对照组）IL-4基因启动子区－589位点和－33位点单核苷酸多态性进行检测，并采用呼吸评分法对RSV毛细支气管炎患儿进行病情严重度的评估。结果 RSV毛细支气管炎组IL-4基因－589位点CC、CT、TT基因型分布频率分别为1.4%、21.1%、77.5%，正常对照组为1.7%、34.0%、64.4%，差异有统计学意义(P=0.005)；RSV毛细支气管炎组IL-4基因－589位点C等位基因频率为11.9%，T为88.1%，正常对照组分别为18.6%和81.4%，差异有统计学意义 (P=0.003)。RSV毛细支气管炎组IL-4基因－33位点CC、CT、TT基因型分布频率分别为1.4%、20.6%、78.0%，正常对照组为2.3%、35.6%、62.0%，两组差异有统计学意义(P=0.001)； RSV毛细支气管炎组IL-4基因－33位点C等位基因频率为11.7%，T为88.3%，正常对照组分别为20.1%和79.9%，两组差异有统计学意义（P=0.000）。单倍型分析显示IL-4－589位点和－33位点存在连锁不平衡（D′=0.75），且两位点T-T单倍型频率在RSV毛细支气管炎组与对照组间的差异亦有统计学意义(P=0.000)。RSV毛细支气管炎组中携带IL-4－589TT基因型患儿的呼吸评分显著高于－589CT基因型患儿（P=0.002）；－33TT基因型患儿呼吸评分也显著高于CT基因型患儿（P=0.001）。结论 IL-4基因－33位点、－589位点C/T单核苷酸多态性与RSV毛细支气管炎易感性和严重度有关。

Objective To investigate the relationship between the polymorphism of loci 589C/T(rs2243250) and 33 C/T(rs2070874) of gene promoter region of interlukin-4 (IL-4) and susceptibility and severity of respiratory syncytial virus (RSV) bronchiolitis and to explore the effects of differences of genetic mechanisms on the incidence and prognosis of RSV infection. Methods Polymorphism of IL-4-589C/T and IL-4-33C/T of 218 patients with RSV bronchiolitis (RSV bronchiolitis group) and 303 healthy controls (control group) were detected by MGB-Taq Man probe method and the severity of RSV bronchiolitis was evaluated by the respiratory scoring system. Results The frequencies of CC, CT and TT genotypes of IL-4-589 of the RSV bronchiolitis group were 1.4%, 21.1%, and 77.5% and those of the control group were 1.7%, 34.0%, and 64.4%, respectively. The differences were statistically significant (P=0.005). The frequencies of all elomorphic genes C and T of IL-4-589 of the RSV bronchiolitis group were 11.9% and 88.1% and those of the control group were 18.6% and 81.4%, respectively. The differences were statistically significant (P=0.003). The frequencies of CC, CT and TT genotypes of IL-4-33 of the RSV bronchiolitis group were 1.4%, 20.6%, and 78.0% and those of the control group were 2.3%, 35.6%, and 62.0%, respectively. The differences of two groups were statistically significant (P=0.001). The frequencies of all elomorphic gene C and T of IL-4-33 of the RSV bronchiolitis group were 11.7% and 88.3% and those of the control group were 20.1% and 79.9%, respectively. The differences were statistically significant (P=0.000). Haplotype analysis found linkage disequilibrium at IL-4-589 and IL-4-33 (D′=0.75). The differences of the frequency of T-T haplotype of IL-4-589 and IL-4-33 of two groups were statistically significant (P=0.000). The clinical respiratory scores of patients with IL-4-589TT in the RSV bronchiolitis group were significantly higher than those of patients with IL-4-589CT (P=0.002). The clinical respiratory scores of patients with IL-4-33TT were significantly higher than those of patients with IL-4-33CT (P=0.001). Conclusion The polymorphism of IL-4-589C/T and IL-4-33C/T was relevant to the susceptibility and severity of RSV bronchiolitis.