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 molecule 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.