Immunoglobulin E (IgE)
Immunoglobulin E (IgE) plays an important role in immunological protection against parasitic infections and in allergy (type 1 hypersensitivity). Type 1 hypersensitivity is characterized by the occurrence of allergic reactions immediately following contact with an allergy - initiating antigen (allergen). The binding of the allergen to sensitized mast cells or basophilic cells leads to cross - linking of the IgE on the cell membrane. This in turn causes cell degranulation and the release of factors (e.g. histamine), which produce the typical symptoms of type 1 hypersensitivity.
The IgE concentration in serum is normally very low (< 0.001 % of the total serum immunoglobulin). The IgE concentration is age - dependent, with the lowest values being measured at birth. Its concentration gradually increases and becomes stabilized between the age of 5‑7, although the IgE values vary greatly within particular age groups. In infants and small children with recurrent respiratory tract diseases, the determination of IgE is of prognostic relevance.
As IgE is of importance in allergies, elevated IgE concentrations can be found in patients with allergic diseases such as hay fever, atopic bronchitis and dermatitis. Normal IgE values do not, however, mean that an allergic disease can be ruled out. For this reason the quantitative determination of serum IgE concentrations for clinical differentiation between atopic and non - atopic diseases is only useful in combination with other clinical findings.
Elevated serum IgE concentrations can also occur in non - allergic diseases, e.g. bronchopulmonary aspergillosis, Wiskott - Aldrich syndrome, hyper‑IgE syndrome, IgE myeloma, and parasitic infections.
SI units Conversion Calculator. Convert Immunoglobulin E (IgE) level to IU/mL, ng/mL, ng/dL, ng/100mL, ng%, µg/L . Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for Immunoglobulin E (IgE) unit conversion to IU/mL, ng/mL, ng/dL, ng/100mL, ng%, µg/L .