IL-13 R130Q single nucleotide polymorphism in asthmatic Egyptian children

Abstract

Background: Asthma and its associated phenotypes are under a substantial degree of genetic control. The common variant IL-13 gene polymorphism R130Q is reported to be associated with the risk of development of asthma in some populations. Objective: We sought to study the association of IL-13 genetic variant R130Q with bronchial asthma in Egyptian children and its relation to various clinical and laboratory phenotypes of the disease. Methods: IL13 gene polymorphism (R130Q) was detected by PCR amplification followed by sequencing using pure script total DNA in 20 asthmatic patients in acute exacerbation. The results were compared to 20 healthy age and sex matched children. Results: Asthmatic children had significantly higher frequency of distribution of R130Q genotype (50%) than controls (15%). The serum total IgE as percent of high normal for age was significantly higher in asthmatic patients as compared to controls with a mean of 208.77 ±237.06% and 14.21 ± 8.08% respectively. No significant difference was observed in the mean AEC(as a percent of high normal for age) of both groups (80.85 ± 116.4% and 82.50 ± 81.4% respectively). No significant differences were observed between patients with IL-13 polymorphism R130Q and those without such polymorphism as regards family history, relation of exacerbations to upper respiratory tract infections, history of food allergy or asthma grading. Serum total IgE was significantly higher in asthmatics with GA genotype as compared to those with GG genotype with a mean of 373.25 ± 238.11% and 44.28 ± 42.65% respectively. A similar finding was also observed among the control group with a mean of 28.03 ± 9.12% and 11.77 ± 5.00% respectively. Finally a significantly higher AEC was observed in controls with GA as compared to GG genotype with a mean of 250.00 ± 51.96% versus 52.94 ± 36.87% respectively. Conclusion: The common variant IL-13 gene polymorphism R130Q is frequently associated with pediatric asthma. This variant is more active than the wild type in inducing allergic inflammation as reflected by the higher serum total IgE and AEC. Hence, IL-13R130Q may be candidate for future gene therapy targeted at reducing the ill-effects of this polymorphism.

Keywords: IL-13R130Q – bronchial asthma - pediatrics

Egypt J Pediatr Allergy Immunol 2010;8(1):9-18