Activation of DP2 on TH2 cells has been shown to cause an increase in the ability of these cells to produce IL-2, IL-4, IL-5, and IL-13.28,29 In turn, these cytokines could regulate key features of severe asthma, as suggested by preclinical studies showing that DP2 antagonism significantly reduced allergen-induced inflammatory changes within mouse airways.18 This evidence concerns the gene IL5 and asthma.