To determine the effect of the 4 signals on IL1RL1 expression in cultured bronchial epithelial cells (BECs), we examined the effect of SNPs on baseline expression of IL1RL1 mRNA isoforms and soluble IL1RL1 (IL1RL1-a) protein in human BECs (HBECs) isolated from asthma patient donors and cultured in vitro (Figure 3 and Supplemental Figures 3 and 4). This evidence concerns the gene IL1RL1 and asthma.