Allergy

According to the World Health Organization, 10-20 % of the world’s population suffers from allergic bronchial asthma, allergic rhinitis, atopic dermatitis and other allergic reactions, moreover, the number of such patients increases every year. According to statistics, from 5 to 15% of children have food allergies, which further leads to the development of various allergic diseases.

Allergy or hypersensitivity is a state of altered reactivity of the body in the form of its increased sensitivity to repeated exposure of substances called allergens. As a result of repeated contact with the allergen, an excessively strong immune reaction of the body occurs, accompanied by tissue damage. One of the mechanisms underlying this process is mast cell degranulation mediated by immunoglobulin class E (IgE). According to the literature data, in an adult, the normal concentration of IgE can reach 100 IU/ml and decreases in the elderly. During allergy the IgE level can rise to 2000 IU/ml and above.

Among often diseases that accompanied by an increase in total IgE in the blood, as well as the presence of specific IgE are allergic rhinitis, atopic bronchial asthma, atopic dermatitis, urticaria, aspergillosis and helminthiases, etc. Less common diseases with hyper-IgE syndrome include congenital immunodeficiencies (Job syndrome, DiGeorge syndrome), selective IgA deficiency, WiskottAldridge syndrome and IgEmyeloma. Also, in clinical practice, there are often cases of elevated IgE levels associated with the action of several medications.

Nowadays, the methods of in vitro allergy diagnostics are becoming increasingly popular, one of which is ELISA for the determination of the total IgE content. This method is characterized by several advantages: it has no contraindications to the test, it does not cause additional sensitization and there is no risk of anaphylactic reactions. Most test systems are based on the «sandwich» ELISA, in which the use of monoclonal antibodies to human immunoglobulins E provides high sensitivity and specificity of the analysis. Standardization of the quantitative determination of IgE in human serum or plasma is ensured by using for the manufacture of internal calibrators ELISA kits of the WHO International Standard with an established concentration of human IgE in international units IU/ml.

Since the ELISA method is a highly sensitive and specific analysis and has no contraindications for its application, it can be widely used for the diagnosis of allergic diseases.

Allergic diseases are among the most common diseases in the world and the severity of these conditions continues to increase. Allergy, or hypersensitivity, is a state of altered reactivity of the body in the form of increased sensitivity to repeated exposure to substances called allergens. As a result of repeated contact with the allergen, an excessively strong immune reaction of the body occurs, accompanied by tissue damage. One mechanism underlying this process is immunoglobulin E (IgE)-mediated mast cell degranulation.

The most common allergic conditions that require proper diagnosis are: anaphylaxis, allergic rhinitis, allergic conjunctivitis, bronchial asthma, etc. Accurate diagnosis coupled with optimal therapy requires the use of appropriate tests to confirm sensitization to a specific allergen and detailed information about the effect of the suspected allergen.

To diagnose in vivo allergies, several types of skin tests are used (skin prick test, intradermal test, patch test). However, the use of these samples has a number of significant limitations, namely, the need for a highly qualified doctor conducting the test and the lack of laboratories conducting these studies. In addition, in vivo diagnosis is rarely performed in children due to possible adverse reactions.

However, in vitro diagnostics of IgE-mediated allergic diseases are useful for identifying the causative allergen and usually include the following laboratory approaches:
1) determination of the level of total IgE;
2) study of the concentration of specific IgE to various allergens - is the most commonly used in vitro
diagnostic approach, performed using a single or multiplex strategy;
3) basophil activation test (BAT), which is quite specific, but difficult to perform, and therefore limited to selected situations.

Today, to detect specific antibodies of the IgE class, the enzyme-linked immunosorbent assay method, which provides high sensitivity and specificity, has become widely used. A separate supply of a wide range of biotinylated allergens, depending on the needs of the diagnostic laboratory, ensures maximum convenience and cost-effectiveness of the study.