Abstract： IgE antibodies are involved not only in the immune defense against parasites,but also in the pathogenesis of allergic diseases and anaphylaxis.Allergen-induced crosslinking of IgE bound to FcεR1 on mast cells triggers degranulation and may initiate an allergic reaction.1 Although IgE is a major player in allergic responses,IgE regulation and the molecular pathway underlying IgE+ B-cell maturation remains elusive.In an exciting report published in the April issue of Nature Immunology,Talay and colleagues demonstrate a new model for IgE switching and memory in vivo.2 In contrast to the current paradigm,IgE+ memory B cells and plasma cells develop through a germinalcenter (GC) IgE+ intermediate,without the need of a transitional IgG1 phase.Furthermore,IgE+ memory B cells,and not IgG1+ memory B cells,are the source of cellular IgE memory.