Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Medical Biochemistry

Different genes are associated with categorical classifications of asthma severity. However, continuous outcomes should be used to catch the heterogeneity of asthma phenotypes and to increase the power in association studies. The aim of our work is to investigate whether there is association between single nucleotide polymorphism (SNPs) in 3 candidate genes of IL-13/IL-4RÜ signaling pathway and the severity of bronchial asthma. Sixty subjects were enrolled in this study divided into 3 main groups: healthy control group (20 subjects), patients with severe bronchial asthma (20 subjects) and patients with mild bronchial asthma (20 subjects). Each group is subdivided into smokers and non smokers. IL-13 C1923T, IL-4 C-590T and IL-4 RA 175V were assessed using restriction fragment length polymorphism (RFLP). Results revealed that polymorphism of IL-13 C1923T genotypes and T allele as well as polymorphism of IL-4 R 175V genotypes and G allele are correlated to severity of asthma on one hand and with smoking status of patients on the other hand. These data suggest that genetic variants in IL-13/IL-4RÜ signaling pathway may be involved in the development of severe asthma. In addition, a new pattern of biological interaction that affects the severity of asthma is described between SNPs of both IL-13 C1923T and IL-4 RA 175V and smoking

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