IL33 rs1342326 gene variation is associated with allergic rhinitis at school age after infant bronchiolitis

Interleukin (IL)-33, encoded by the IL33 gene, is associated with allergy and asthma. We evaluated IL33 rs1342326 polymorphism in relation to asthma, asthma medication and allergic rhinitis after infant bronchiolitis.

IL33 rs1342326 polymorphism was studied in children, who were hospitalised for bronchiolitis at age younger than 6 months and who were prospectively followed until 5-7 years (N = 141) and 11-13 years (N = 125) of ages.

The presence of the wild AA vs variant AC or CC genotypes of the IL33 rs1342326 showed no significant associations with previous or current asthma at the mean ages of 6.4 or 11.7 years. However, 22.5% of children with the variant genotype used inhaled corticosteroids at the 5-7 years of visit (adjusted OR: 2.94, 95% CI: 1.04-8.33 vs those 8.9% with the wild genotype). The variant IL33 rs1342326 genotype was associated with allergic rhinitis at 6.4 years (adjusted OR: 2.17, 95% CI: 1.01-4.76) and 11.7 years (3.23, 1.18-9.09) of ages.

The frequent use of asthma control medication in 6.4-year-old children with IL33 rs1342326 polymorphism suggests that this variation may increase susceptibility to severe asthma at preschool age. The IL33 rs1342326 variant genotype was associated with a 3-fold risk of allergic rhinitis at school age.