簡要描述：The human chemoattractant receptor-homologous molecule (CRTH2, GPR44, G protein-coupled receptor 44) maps to chromosome 11q12-q13.3 and encodes a 472 amino acid G protein-coupled leukocyte chemoattractant receptor. Chemoattractant receptors present on Th2 cells respond to parasites and play a central role in allergic inflammation; they are absent on type 1 T helper (Th1) cells, which address intracellular bacteria and many viruses. CRTH2 contains seven putative transmembrane domains and med