Consistent with the potent inhibitory activity of PGE2-EP4 signaling on ILC2 in vitro, intranasal administration of PGE2 or the EP4-selective agonist PGE1-alcohol attenuates IL-33-induced allergy in vivo as demonstrated by the reduced number of eosinophils and other inflammatory cells in BALF and improved histology of the lung tissue. Here, IL33 is linked to Allergy.