Platelet Factor 4: Production, Structure, and Physiologic and Immunologic Action

Platelet factor 4 (PF4) is a protein found in the megakaryocyte and platelet α-granule (1,2). Immunocytochemistry studies have shown that it is now and in the mast cell granules (3) and human umbilical vein endothelial cells, but not artery (4). The early work PF4 reviewed elsewhere (5-7). Human platelets contains approximately 18 ± 4 micrograms PF4/109 (8).

Thrombin-sensitive protein, platelet-derived growth factor, and platelet derived basic protein, such as β-thromboglobulin globulin (β-TG) of the compound were found in platelet α-granules in addition to PF4. All appropriately stimulated secretion of platelets, for example, since thrombin is a strong stimulus, these compounds are present in much higher concentration in the serum than in plasma (e.g., 5334, and 1.8 ng / ml PF4. [9] ). After contacting the platelets with collagen in damaged blood vessels, for example, they are also secreted.