GWAS-identified variants to allergic disease and early environmental exposure in Chinese schoolchildren with allergic rhinitis induced by house dust mite.

Background: There is growing evidence that environmental exposure in early life is associated with the development of childhood allergic rhinitis.

Objective: To investigate whether polymorphisms in previously published genome wide association studies (GWAS) allergic disease loci are associated with childhood house dust mite-induced allergic rhinitis (HDM-AR) and interaction effects of genetic and environmental factors on it.

Methods: 156 cases diagnosed by HDM-AR and 173 controls were enrolled. Potential confounders were analyzed by using Logistic regression. Twenty-one single nucleotide polymorphisms (SNPs) of GWAS-related allergic diseases including EMSY-LRRC32, IL18R1, IL18RAP, IL13, IL4, HLA region, KIF3A were genopyped and analyzed using the improved multiplex ligation detection reaction (imLDR) technique in all the subjects.

Results: Only IL18R1_rs2287037 was associated with HDM-AR in children. After adjusting for several likely confounders, the protective TT genotype of IL18R1_rs2287037 was found in the population analyzed with the fittest recessive model. (adjusted odds ratio [aOR]: 0.44; 95% confidence interval [CI]: 0.21-0.95). The rs2287037_ TT might interact with early-life exclusive breastfeeding in the first 4 months (aOR: 0.33; 95%CI: 014-0.97) or full-term birth (aOR: 0.45; 95%CI: 0.19-0.95) exposure to decrease the risk of HDM-AR.

Conclusions: These data suggest that IL18R1 polymorphism may play a role in controlling risk to HDM-AR and underline the importance of early environmental exposure into studies of genetic risk factors.