Polymorphism of IL13 (rs1295685) Gene and Its Serum Level in a Sample of Iraqi Patients with Allergic Asthma

Abstract

Interleukin 13 (IL-13) is an immune-regulatory cytokine, primarily secreted by activated T Helper-Type (Th) 2 cells, which inhibits inflammatory cytokine production in allergic asthma. Single nucleotide polymorphism SNP (1295685A˃G) of the IL-13 gene and its serum level was included in a case-control study on 60 Iraqi asthmatics and 60 controls. ELISSA-linked immune-sorbent assay was used to estimate blood serum levels. The real-time high-resolution melting polymerase-chain-reaction (Real-time PCR-HRM) method was used to determine this variant. The results showed that the mean level of IL-13 was high in asthmatic patients compared to the control group (22.90 pg/ml vs.13.99 pg/ml), respectively, and significant differences were (p=0.0001). ROC curve analysis of IL-13 described an AUC of 0.882. Regarding the allele and genotype of (A˃G 1295685) SNP, there were clear differences between patients and the control group, as the frequency of the GG +AG genotype was significantly higher (p=0.001) in patients compared to the control group (81.7%vs.23.3%) respectively, and the G allele frequency was higher in patients compared to the control group (48.8% vs. 16.6%) respectively, with significant difference (p=0.001). In conclusion, increased levels of IL-13 in serum and the presence of the G allele, GG + AG genotype in the IL13 gene may be associated with the pathogenesis of allergic asthma in Iraqi adult patients. Keywords: Allergic Asthma, IL-13, SNP, RT-HRM-PCR