IL33 and asthma: Genome-wide association studies (GWAS) strongly link several single nucleotide polymorphisms (SNPs) in both IL-33 and ST2 to asthma [37]; interestingly, many of the most strongly correlated SNPs in IL-33 occur in the 5 ́ region of the gene important for inducing gene transcription, implying that the cells capable producing IL-33 upon stimulation rather than those with constitutive IL-33 expression play roles in asthma disease pathogenesis.