 The function of FPR3 is not clear.Confusingly, there are two "standard" nomenclatures for FPR receptors and their genes, the first used, FPR, FPR1, and FPR2 and its replacement, FPR1, FPR2, and FPR3.The latter nomenclature is recommended by the International Union of Basic and Clinical Pharmacology and is used here.