The IL1A genotype is associated with nasal polyposis in asthmatic adults.

Abstract

Nasal polyposis (NP) is a chronic inflammatory disease often found coexisting with asthma. As this disorder tends to cluster in families, a genetic predisposition has been suggested. Interleukin-1 (IL-1) has been proposed to play a role in the pathogenesis of NP. We analysed the single G-to-T base exchange polymorphism in exon 5 at +4845 of the gene encoding IL-1alpha (IL1A) and the C-to-T base exchange polymorphism at -511 of the gene encoding IL-1beta (IL1B) in a population-based sample of adult asthma patients (n = 245). The data were assessed for correlation with data on history of NP and other phenotype-related characteristics. The prevalence of NP in our study group was 14.3%. The distribution of the IL1A genotype differed significantly between asthmatics with and without NP (P = 0.005). The risk of NP was markedly increased in allele G homozygous subjects (OR = 2.73; 95%CI = 1.40-5.32). In the case of IL1B we found no significant associations. Asthmatics with NP had more symptoms than others, but lung function and blood eosinophil counts were similar. Our study demonstrates an association of IL1A with NP inasthmatic patients and addresses the role of IL-1alpha as an inflammatory modulator in the pathogenesis of this disease.