CXCR4 and helminthiasis: Little is known of these receptors in the setting of helminth infection, but ACKR3 expression in wild mice (Apodemus sylvaticus) is one of 4 loci to correlate most negatively with burdens of H. polygyrus72, while its ligand CXCL12 (which is the canonical ligand for CXCR4) is required for immunity to a tissue-dwelling nematode Litomosoides sigmondontis73.