CD47 and Thrombocytopenia: Anemia and thrombocytopenia following infusion of anti-CD47 is a result of the expression of CD47 on erythrocytes and platelets; on the former, CD47 normally acts to prevent the efferocytic clearance of non-senescent erythrocytes by splenic macrophages, while on the latter, CD47 prevents spontaneous platelet activation.