Role of IL13 genetic polymorphism in the development of bronchial asthma in children

Abstract

Bronchial asthma is a multifactorial disease, with both environmental factors and genetic predisposal affecting its development. A number of gene associations have been obtained between polymorphisms of cytokine genes produced by different types of immune cells and asthma development. Interleukin-13 is involved in allergic inflammation, increased bronchial hypersensitivity, regulation of eosinophil levels and IgE production by B cells, thus making it promising for studying IL13 gene polymorphisms in bronchial asthma coupled to development of the disease. The aim of this study was to investigate possible association between asthma and IL13 rs1800925 polymorphism in the children of Caucasian origin in Eastern Siberia. Four groups of patients with asthma were examined (mean age 12.8±1.2 years): with a controlled (n = 95) and uncontrolled course (n = 107), with severe (n = 71) and moderate severity (n = 131) diseases. The control group consisted of healthy individuals: children (n = 33) and adults (n = 102). DNA was isolated with sorbent method; genotyping was carried out using RT-PCR using specific oligonucleotide primers and fluorescent TaqMan probes. The allele and genotype frequencies were compared by the χ-square test using an online calculator. The odds ratio (OR) with a 95% confidence interval (CI) was performed to link genetic markers with pathological phenotypes. The CT IL13 rs1800925 genotype was shown to be associated with moderate asthma and cases of uncontrollable clinical course, whereas the TT genotype was associated with severe asthma. Thus, rs1800925 polymorphism of IL13 gene (the T* variant is known to be associated with increased IL-13 expression) may be associated with bronchial asthma in children. Our data are consistent with results of other authors. E.g., Liu Z. et al. revealed an association between rs1800925 IL13 and the risk of developing asthma in children, with CT and TT genotypes being more common in the patient group. Radhakrishnan A. et al., was studied rs1800925 IL13 in adult population of Malaysia and found that the T* allele frequency in the group of patients significantly exceeds the frequency of this allele in the control group. Thus, the results of our study showed that IL13 rs1800925 polymorphism is associated with bronchial asthma in children, especially, with level of its control and severity of the disease.