Recent progress in work on PGD2 antagonists for drugs targeting allergic diseases.

Prostaglandin (PG) D2, the major cyclooxygenase metabolite generated from immunologically stimulated mast cells, is thought to contribute to the pathogenesis of allergic diseases due to its various inflammatory effects. However, the lack of PGD 2 (DP) receptor antagonists has limited the study of its essential roles in the disease state. Recent discoveries of several DP receptor antagonists, the development of the mutant mouse and the discovery of a second PGD 2 receptor, CRTH2 (chemoattractant receptor-homologousmolecule expressed on Th2 cells) receptor, have revealed the crucial roles of PGD 2 and CRTH2 receptors in allergic disorders. This review presents biological evidence that PGD 2 plays an essential role in allergy disorders and discusses the therapeutic possibilities of recently reported PGD 2 antagonists.