However, variants of these mAbs, as well as a recently developed anti-FcγRIIa antibody (VIB9600) lacking the capacity to engage FcγR via their Fc regions, failed to induce anaphylaxis or immune thrombocytopenic purpura (ITP), and protected FcγRIIa transgenic mice from near lethal doses of IgG ICs [222,223]. The gene discussed is FCGR2A; the disease is autoimmune thrombocytopenic purpura.