Of note, PGD2 and DP2/CRTH2 levels are increased in asthma severity in BAL (151, 152), and the DP2/CRTH2 antagonist OC000459 improves FEV1 and the quality of life of subjects with eosinophilic uncontrolled asthma and steroid-free subjects with moderate persistent asthma (155, 156). Here, PTGDR2 is linked to chronic asthma.