Pro-platelet basic protein (PPBP) is also known as Chemokine (C-X-C motif) ligand 7 (CXCL7) and nucleosome assembly protein (Nap-2). Nap-2 / PPBP / CXCL7 is released in large amounts from platelets following their activation and is a platelet-derived growth factor that belongs to the CXC chemokine family. This growth factor is a potent chemoattractant and activator of neutrophils. Nap-2 / PPBP / CXCL7 has been shown to stimulate various cellular processes including DNA synthesis, mitosis, glycolysis, intracellular cAMP accumulation, prostaglandin E2 secretion, and synthesis of hyaluronic acid and sulfated glycosaminoglycan. It also stimulates the formation and secretion of plasminogen activator by synovial cells. Nap-2 is a ligand for CXCR1 and CXCR2, and Nap-2, Nap-2 (73), Nap-2 (74), Nap-2 (1-66), and most potent Nap-2 (1-63) are chemoattractants and activators for neutrophils.