CD47, also known as Integrin-Associated Protein (IAP) ,is a membrane protein of about 50 kd with an IgV-like extracelluluar domain, a five membrane-spanning segment and a short terminal cytoplasmic region.It is widely expressed on many cell types and often associated with beta 3 integrins.The significance of this molecules is recently drawing increasing attention.It has been reported that CD47 functions as a self marker.Red cells lacking CD47 were rapidly cleared from the bloodstream by splenic macrophages.By binding to SIRPalpha,CD47 controls hemostatic innate immune functions,such as phagocytosis and cell trafficking.