PTGDR2 and allergic disease: CRTH2+ ILC2 were found to accumulate in esophageal tissues of patients with the allergic disease eosinophilic esophagitis (95), in nasal polyps of patients with chronic rhinosinusitis (36), an allergic condition characterized by high levels of IL5 and IL13, and in the inflamed skin of patients with atopic dermatitis (96), suggesting they can contribute to type 2 cell-mediated disease.