FCGR2B and allergic disease: The whole plethora of activities and functions in which FcγRIIB is involved are still under investigation, but, in general, two therapeutical principles have been developed: reducing the binding of IgGs to FcγRIIB to prevent the inhibitory effects of therapeutic mAbs targeting tumor cells and the direct targeting of FcγRIIB to achieve the inhibition of specific IG-producing B cells in allergies.