Alaq Kareem Jawad, Ahmed Flayyih Hasan, Fatma Ayadi
Background/Aims: Allergic rhinitis is a common chronic inflammatory disease affecting millions of people worldwide and substantially impairing quality of life. This study aimed to investigate the association of the IL-4 rs2243250 polymorphism with allergic rhinitis, inflammatory markers, and leukocyte profiles. Methods: A total of 182 participants were included, comprising 91 patients with allergic rhinitis and 91 healthy controls. Peripheral blood samples were collected for complete blood count, DNA extraction, and measurement of IL-4, IL-13, and IgE levels using enzyme-linked immunosorbent assays. Skin prick testing for weed, grass, tree, and mite allergens was performed to confirm IgE-mediated sensitization. The IL-4 rs2243250 polymorphism was detected by polymerase chain reaction followed by restriction fragment length polymorphism analysis using the AvaII restriction enzyme. Results: Significant differences (P < 0.001) between patients and controls were observed for all investigated immunological markers and differential white blood cell counts. For rs2243250, the CC genotype was associated with a reduced likelihood of allergic rhinitis (OR = 0.25; 95% CI: 0.11–0.55), whereas the TT genotype was associated with an increased likelihood (OR = 3.8; 95% CI: 1.82–8.17). Similarly, the C allele was associated with reduced disease likelihood (OR = 0.35; 95% CI: 0.23–0.53), while the T allele was associated with increased likelihood (OR = 2.88; 95% CI: 1.88–4.41; P < 0.001). Significant positive correlations among several white blood cell types were also observed. Conclusion: The findings demonstrate an association between the IL-4 rs2243250 polymorphism and allergic rhinitis. The C allele and CC genotype were associated with reduced disease likelihood, whereas the T allele and TT genotype were associated with increased likelihood. These genetic associations, together with alterations in inflammatory markers and leukocyte profiles, may contribute to understanding susceptibility to allergic rhinitis.