NCIt definition : An immunoglobulin isotype (subclass). This isotype has the unique ability to bind
with high affinity to IgE receptors (FceRI) on mast cells and basophils and induce
degranulation and cytokine production by these cells when they are crosslinked by
antigen. In addition to a central role in atopy and allergic responses, it has been
speculated that IgE-mediated mast cell degranulation, by its release of mediators
that increase vascular permeability, has an important role in the initiation of immune
response in general.;