IGHE and anaphylaxis: Alpha‐Gal‐sensitized α1,3GalT‐KO mice displayed increased levels of alpha‐Gal‐specific IgE and IgG1 antibodies, along with a higher number of basophils at the sensitization site, as well as alpha‐Gal‐specific B cells, germinal center B cells, and B cells of the IgE and IgG1 isotypes in skin‐draining lymph nodes. Furthermore, the murine model developed systemic anaphylaxis, dependent on interleukin‐4 (IL‐4), when challenged with alpha‐Gal‐containing glycoproteins and glycolipids