Immunoglobulin E (IgE)

Immunoturbidimetry assay

Product description:

IgE is the least abundant serum immunoglobulin and is involved with protection from parasitic disease and allergic responses. IgE does not fix complement and it binds with a high affinity to the specific Fc receptors on basophils, eosinophils and mast cells even before interacting with antigen.Elevation of total serum IgE levels is typically found in many atopic patients, and in predisposed individuals. Allergan specific IgE is then bound to the high-affinity IgE receptor, Fc?RI, and subsequently expressed on the surface of several key inflammatory cells, including mast cells, basophils, and dendritic cells. Allergen binds to the Fab portion of the IgE molecule. Cross-linking of two adjacent IgE molecules on the surface of allergic effector cells initiates intracellular signalling pathways that result in the release of preformed and rapidly synthesized mediators. This type I hypersensitivity reaction is central to the pathogenesis of atopic disordersor immediate hypersensitivity reactions such as hay fever, asthma, hives and anaphylaxis.

Although IgE is commonly involved in allergic reactions, the main function of IgE seems to be to protect the host against invading parasites. Eosinophils have Fc receptors for IgE and binding of eosinophils to IgE-coated helminths results in killing of the parasite. Since serum IgE levels rise in parasitic diseases, measuring IgE levels is helpful in diagnosing parasitic infections. Binding of the antigen to IgE on the cells results in immediate release of various mediators, including histamine, serotonin, leukotrienes and others. Elevated serum immunoglobulin E (IgE) levels may correlate with disease activity including nephritis in patients with SLE but without known allergies. High serum IgE concentration is also associated with IgE ANAs but not with the presence of IgE antibodies to allergens. IgE ANA observed in 32% of patients with SLE are heterogeneous with multiple specificities including dsDNA, Sm, SSA/Ro, and SSB/La antigens of IFN. A recent Cystic Fibrosis Consensus Document recommends IgE levels higher than 417 IU/mL or higher than 1000 ng/mL as being consistent with ABPA. Also, the Cystic Fibrosis Foundation has recently suggested that all CF patients have yearly determination of serum IgE.