NFATC2-deficient mice have attenuated IgE-mediated anaphylaxis. (A-B) ASNase-immunized NFATC2 KO mice have fewer peripheral blood basophils than immunized WT mice. (C) Immunized KO mice have decreased basophil ASNase-specific recognition relative to WT mice, but no difference in the binding to ASNase ICs. (D) Basophil FcεRI expression increases after ASNase immunization but is lower in KO mice relative to controls. (E) Basophil FcγRIIB/RIII expression increases after ASNase immunization but is similar between WT and KO mice. (F-G) IgE- and IgG-mediated basophil activation is attenuated in KO mice compared with WT controls, but there is no difference in ASNase IC–induced basophil activation between WT and KO mice. **P < .01; ***P < .001; ****P < .0001.