FCGR3A and autoimmune thrombocytopenic purpura: In accordance with the notion that FcγRIIIa+ splenic monocytes are particularly important for the clearance of platelets, only the higher affinity-allele of the FcγRIIIa polymorphism at position 158 [F/V, with 158 V having higher affinity for IgG1 and IgG3 (200)] has been found to be associated with ITP (48, 50–53).