CRIPTO3 and leukocyte adhesion deficiency: CR3 has previously been implicated in FcγR-mediated phagocytosis, for example, anti-CR3 blocking antibodies have been shown to impair the phagocytosis of IgG-opsonized RBCs (41, 42), and neutrophils from patients with leukocyte adhesion deficiency, an autosomal recessive disorder caused by mutations of the β2-chain of CR3, exhibit decreased ability to ingest IgG-opsonized RBCs (43).