FCER2 and asthma: In addition to mediating acute degranulation of mast cells and basophils through its binding to FcεRI, which may at least exacerbate asthma in some individuals, IgE may play important, less well-defined roles in the genesis of asthmatic mucosal inflammation, for example, by facilitating antigen capture and presentation by subjects of mucosal dendritic cells expressing FcεRI and B cells themselves which express FcεRII (CD23).