Its major physiologic role appears to be neutralization of heparin-like molecules on the endothelial surface of blood vessels, thereby inhibiting local antithrombin activity and promoting coagulation.

As a strong chemoattractant for neutrophils and fibroblasts, PF4 probably has a role in inflammation and wound repair.

[5][7] PF4 is chemotactic for neutrophils, fibroblasts and monocytes, and interacts with a splice variant of the chemokine receptor CXCR3, known as CXCR3-B.

[9] PF4 autoantibodies have also been found in patients with thrombosis and features resembling HIT but no prior administration of heparin.

[16] This article incorporates text from the United States National Library of Medicine, which is in the public domain.