While the humanized anti-CD47 antibody (Hu5F9-G4) used in this study has been shown to block the CD47-SIRPα interaction and induce phagocytosis of leukemia cells[26] we can not rule out the possibility of Fc mediated opsonization as human macrophages express high affinity Fc receptor FcRγ1. The gene discussed is SIRPA; the disease is leukemia.