CRTH2 (GPR44)

Chemoattractant receptor homologous molecule of Th2 cells (CRTH2) has been shown to mediate the chemotaxis of eosinophils, basophils and Th2-type T lymphocytes. The major mast cell product prostaglandin (PG) D(2) is considered to be the principal ligand of CRTH2.

CRTH2 is the most reliable marker for the detection of circulating human type 2 Th and type 2 T cytotoxic cells in health and disease. CRTh2 receptors, expressed on eosinophils, basophils, T-helper 2 cells, macrophages, and neutrophils are known to be involved in chemotaxis and activation of these cells, which form the key events initiating the inflammatory response in allergic diseases.