Total IgE

Why this test?

Determination of total IgE is carried out to detect allergies. Also, this indicator is used as an additional method for differentiating atopic diseases with an allergic component among many pathologies that are clinically manifested as asthma, frequent respiratory tract diseases, chronic rhinitis, dermatitis, chronic diarrhea, and others.

In what cases is it prescribed?

For the diagnosis of allergic diseases: bronchial asthma, pollinosis (diseases arising as a result of allergies to plant pollen. These include: hay fever, conjunctivitis, rhinitis, and others. Atopic dermatitis (chronic recurrent inflammatory skin disease, manifested by intense itching ), eczema, food and drug allergy Helminthiasis (diseases caused by parasitic worms-helminths) 

Assessment of the risk of developing allergic diseases in children whose relatives have allergic pathology.

Test information

Immunoglobulin E (IgE) is a class of immunoglobulins that is normally found in small amounts in blood serum and secretions. The structure of IgE is similar to the structure of other immunoglobulins and consists of two heavy and two light polypeptide chains. They are grouped into complexes, so-called domains. Each domain contains approximately 110 amino acids. IgE has five such domains, unlike IgG, which has only four domains. According to the physical and chemical properties of IgE, it is a glycoprotein with a molecular weight of approximately 190,000 Da, consisting of 12% carbohydrates. IgE has the shortest duration of existence (half-life from blood serum 2-3 days), the highest rate of catabolism and the lowest rate of synthesis of all immunoglobulins (2.3 μg/kg per day). IgE is synthesized mainly by plasma cells located in mucous membranes. The main biological role of IgE is its unique ability to bind to the surface of human mast cells and basophils. On the surface of one basophil, there are approximately 40,000 to 100,000 receptors that bind 5,000 to 40,000 IgE molecules. Degranulation of mast cells and basophils occurs when two IgE molecules bound to the cell membrane bind to an antigen, which, in turn, turns on a series of events leading to the release of inflammatory mediators.

In addition to participating in allergic reactions of the I (immediate) type, IgE participates in protective antihelminthic immunity, which is due to the existence of cross-linking between IgE and the antigen of helminths. The latter penetrates through the mucous membrane and settles on mast cells, causing their degranulation. Inflammatory mediators increase capillary and mucosal permeability, resulting in IgG and leukocytes leaving the bloodstream. IgG-coated helminths are joined by eosinophils, which release the contents of their granules and thus kill the helminths. IgE can be detected in the human body as early as the 11th week of fetal development. The content of IgE in blood serum increases gradually from the moment of birth to adolescence. In old age, the level of IgE can decrease.