Background and aim: Interleukin-1 is a pro-inflammatory cytokine found in two forms (α and β). The α form is mainly cell-bound, whereas IL-1β is primarily secreted by macrophages in response to immune system stimulation. We hypothesized that polymorphic variants of interleukin 1 genes may play a role in childhood asthma risk. The aim of this study was to investigate if IL-1α and β polymorphism is associated with asthma in a pediatric population and if the genotype affects its serum level.
Methods: The studied population included 310 children aged 6-18 years old (152 with asthma and 158 healthy children). Genotypes were determined with real-time PCR method using TaqMan Genotyping Assays. Serum level was measured with ELISA Set. Statistical analysis was done in Statistica v.12.0. Linkage disequilibrium and haplotype analysis was done in Haploview v. 4.2.
Results: We found that three IL-1β polymorphisms rs1143634, rs1143633, and rs1143643 were associated with allergic asthma risk (P = 0.034; OR = 1.523; P = 0.024, OR = 1.477; 0.044, OR = 1.420, respectively). We also found a strong linkage disequilibrium between these polymorphisms and CAC haplotype was associated significantly with asthma risk (P = 0.023). For IL1α, we did not observe association with asthma. We then analyzed if IL-1β expression was altered in serum and we found that asthmatic children showed significantly higher IL-1β levels than healthy controls (P = 0.047). No association with asthma was observed for IL-1 α variants.
Conclusions: This study indicates that IL-1β gene polymorphism may affect allergic asthma risk in children.
Keywords: allergic asthma; gene; pediatric population; polymorphism.
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