Association between candidate gene polymorphisms and total IgE in adult subjects with asthma: preliminary results from the GEIRD study

Immunoglobulin E (IgE) plays a crucial role in asthma and allergic diseases. The present analysis is aimed at identifying single nucleotide polymorphisms (SNPs) that are associated with total IgE in adult subjects with asthma. In the Gene Environment Interactions in Respiratory Diseases (GEIRD) study, 274 subjects with asthma (age range: 20-66 yrs; female: 47.1%; presence of atopy as a positive skin prick test to any inhalant allergen: 72.3%) were identified from the general population in Verona (Italy, 2008-2010). A panel of 221 SNPs tagging 50 candidate gene regions was genotyped by a custom GoldenGate Genotyping Assay. The association of each SNP with total IgE was tested by a quasi-gamma regression model, with age and sex as adjusting variables. The Simes multiple-test procedure was used for controlling the false discovery rate (FDR). The SNP-atopy interaction term was tested for the SNPs that were significantly associated with total IgE after FDR correction. SNPs rs946259 in CHI3L1, rs2072862 in IL2RB and rs2238136 in VDR genes were significantly associated with total IgE. The SNP-atopy interaction term was not statistically significant for these polymorphisms. Our preliminary results suggest that different genes influence total IgE regardless of atopy in adult subjects with asthma.