Study On The Polymorphism In IL-4 Receptor Gene In Patients With Childhood Wheezing

Background: Most patients with asthma had childhood wheezing when they were 2 or 3 years of age. It's a great challenge for pediatricians to understand the relationship between childhood wheezing and asthma. Most studies suggest that infection of lower respiratory tract can cause early wheezing. Such patients present polymorphism in certain genes, which is closely associated with later immunoreactions. Human IL-4Rαgene coding sequence is closely related to susceptibility for asthma and idiocratic diseases. It has been verified that IL-4Rαgene sequence-induced amino acid replacement may participate signal transduction. In recent years, studies on the relationship between polymorphism in IL-4R gene and idiocratic diseases and viruses have demonstrated that IL-4Ra gene is an important candidate gene for asthma and idiocratic diseases.Objective: To study the relationship between polymorphism in IL-4R gene and the pathogenesis of childhood wheezing.Methods: The study consisted of 128 children with wheezing and 82 healthy subjects. PCR-restriction enzyme cutting technology was used to detect IL-4R gene I50V and Q576R. The total serum IgE level and peripheral eosinophil count were detected by ELISA.Results: There was a difference in 150, V50, Q576 and R576 allele frequency and genotypic frequency between childhood wheezing patients and normal children. Genotype I50/I1e50 was correlated with the susceptibility for wheezing (p=0.015, OR=0.439, 95%CI= 0.223～0.826). The susceptibility for wheezing was related to the combination of I50/V50 and Q576/R576. There was no statistical differences in serum IgE level and peripheral eosinophil count among different genotypes. In childhood wheezing patients, there was a statistical difference in Q576 and R576 allele frequency and genotype frequency between the two groups (with and without a family history of asthma). But there was no statistical differences in serum IgE level and peripheral eosinophil count.Conclusion: Childhood wheezing is closely related to genetic factors. Children who carry predisposing genes may suffer from frequent wheezing and subsequent asthma. The research suggests that there is significant difference between the wheezing children and healthy children in the constitution of gene II,IV and W. There is significant difference between 150 and V50 in the allele frequency constitutional ratio. There is significant difference between Q576 and R576 in the allele frequency constitutional ratio. The gene type of I50/I50 is related with the susceptibility of wheezing. The combination of I50/I50 and Q576/R576 is related with the susceptibility of the breaking out of the wheezing. The research suggests that there is significant difference among the infants and children who have the family history and those who don't have in the gene type and gene frequency constitution of Q576R.Among the panting children who get the disease from downtake infection, the non acidophil inflammation is the main part in the airflue inflammation.In the initial research, there is no irritation factor affecting wheezing.In infancy, the inflammation of respiratory tract may be Th1 reaction, and wheezing may have nothing to do with increased IgE level. But subsequent allergen irritation may still cause frequent wheezing or asthma.