Immunoglobulins are protein molecules that circulate in the bloodstream. They are part of the body’s immune response to a stimulus perceived as foreign, such as bacteria, parasites, or allergens. There are five classes of immunoglobulins, named G, A, M, E, and D, and abbreviated: IgG, IgA, IgM, IgE, and IgD. Each class has its own characteristics. IgE is an immunoglobulin whose levels in the body rise in certain situations, including in the setting of an allergic response.
Persons with allergy and asthma will often demonstrate elevated IgE blood levels as compared to a normal individual with neither allergy nor asthma. IgE plays an important, central role in several allergic conditions, namely asthma, allergic rhinitis, atopic dermatitis (also known as eczema), certain food allergies (e.g., peanuts and fish), urticaria (hives), and anaphylaxis. Recent understanding of the pivotal role of IgE has led directly to the development of a novel medication that blocks the effects of IgE. By blocking IgE, the allergic response is lessened or eliminated, offering promising treatment of asthma and severe food allergies.