IgE antibodies are one of five immunoglobulin groups: IgM, IgA, IgG, IgE, and IgD. IgE globulin is the last of the immunoglobulin family. Not only does it have a unique chemical structure, but it also has a wide range of physiological functions such as autoimmune processes, parasitic infections, type I hypersensitivity reactions, and even venom defense.