In contrast, in murine studies on ITP (15, 16) and experimental autoimmune encephalomyelitis (EAE) (17), the beneficial effect of IVIg was also observed in FcγRIIB−/− mice, challenging the absolute requirement for FcγRIIB in IVIg-treated mice. Here, FCGR2B is linked to autoimmune thrombocytopenic purpura.