Antibody 8D6, which extends the IgE-Fc as described above (Figure 2d), inhibits FcεRI binding both orthosterically and allosterically, but does not affect the CD23 interaction [38]; this may prove valuable therapeutically for allergic disease if down-regulation of IgE production can be effected through the interaction of 8D6/IgE complexes with mCD23 on B cells. This evidence concerns the gene FCER1A and allergic disease.