CXC chemokine receptors are integral membrane proteins (GPCR-A2) that specifically bind and respond to cytokines of the CXC chemokine family. CXCR1 and CXCR2 (IL8R-α and IL8R–β respectively) are closely related receptors that recognize CXC chemokines that possess an E-L-R amino acid motif immediately adjacent to their CXC motif; they are both expressed on the surface of neutrophils in mammals. While CXCR3 is expressed predominantly on T lymphocytes, the CXCR4 receptor has a wide cellular distribution, with expression on most immature and mature hematopoietic cell types[1].