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A new direction has emerged in the diagnosis of allergic reactions: Molecular diagnosis of allergies is a component allergy diagnosis. The basis of molecular diagnosis of allergies is the identification of sensitization to allergens at the molecular level using natural, highly purified and recombinant allergen molecules, that is, their components, and not extracts.

In the late 1980s, when DNA technology began to be introduced, allergen molecules were characterized and cloned, which helped identify antigenic determinants in various allergic diseases. All this played an important role in the emergence of a new type of diagnostics - molecular diagnostics, which, in turn, contributed to the development of more effective treatment for allergies.

Determination of antibodies to recombinant allergens makes it possible to identify the leading component in the composition of complex allergens at the level of molecular allergology. This allows you to differentiate true and cross allergies. The use of recombinant allergens is a new tool in the diagnosis of type I allergic reactions, which allows one to obtain detailed information about the patient’s sensitization, cross-reactivity with other allergens, to justify the feasibility and predict the effectiveness of allergen-specific immunotherapy (ASIT).

This direction will change views on the examination and treatment of patients and bring them into line with those in world medicine.

There are 3 main advantages of performing this study:

Molecular allergy diagnostics makes it possible to differentiate true sensitization from sensitization due to cross-reactivity. This data will help determine the sources of allergies: one single one, several closely related ones, or many different ones.

Molecular allergy diagnostics will eliminate the need for provocative tests and make it possible to give clearer recommendations regarding the elimination of contact with allergens.

Molecular allergy diagnostics is necessary in the selection of allergen-specific immunotherapy (ASIT); in individuals with polyvalent sensitization, the most accurate way to determine the most important allergen for which ASIT will be performed. It has been shown that the use of molecular diagnostic methods forces a change in ASIT, selected based on the results of skin prick tests.

To begin using allergen components and correctly interpret research results, you need to know basic information about allergen components and their clinical use:

Allergen molecules are given a name, first the first three letters of the Latin name of the genus, then the first letter of the species and an Arabic numeral - the allergen number (the number depends on the order of isolation and/or clinical importance). For example: Birch – Bet v 1, Bet v 2, etc.

The composition of an allergenic substance includes not one, but several protein components that can act as allergens: “major” - the main allergens, others “minor” - minor. Major allergenic components are allergenic molecules to which antibodies are found in more than half - 50% of patients in the population reacting to a given source. They are heat resistant and more immunogenic. Large in size and contained in this allergen in larger quantities. Minor molecules are smaller in size and less immunogenic allergenic molecules, which are usually contained in smaller quantities in the allergen, but are present in many different allergens, sometimes not closely related, providing cross-allergy. That is, allergens with a prevalence of more than 50% are called major, and less than 10% are called minor.

The culprits of allergies include grasses and trees. One of the representatives of trees is birch (Latin name Bétula). An allergy to birch occurs in late April - early May, during the flowering period of this tree. Most often, an allergy to birch pollen manifests itself as hay fever (hay fever) and allergic conjunctivitis with their characteristic symptoms: nasal congestion, thin, clear nasal discharge, itchy nose, sneezing in series, swelling of the eyes and itching, lacrimation. In more rare cases, skin reactions (allergic urticaria), as well as symptoms of intoxication of the body (lethargy, fatigue, irritability) may occur. Many patients with bronchial asthma experience exacerbations during birch flowering.

To determine sensitization to birch as a complex allergen, the following are studied: rBetv 1 PR-10 IgE is the main “major” allergen and rBet v 2 profilin and rBet v 4 are the secondary “minor” ones. A true allergy to birch pollen is confirmed by the presence in the blood of the major allergen rBetv 1 PR-10 IgE. rBetv 1 PR-10 IgE is detected in the majority of patients sensitized to birch pollen.

The structure of rBetv 1 PR-10 IgE is homologous with pollen proteins from other trees from the Birch, Beech, Nut families and taxonomically related fruits (apples, apricots, peaches, cherries), vegetables (carrots, celery) and spices. In addition to respiratory symptoms due to pollen, when eating fruits, some vegetables, and nuts, local manifestations of allergies are observed - oral allergic syndrome in the form of itching, burning, swelling, and redness in the oral cavity. rBet v 2 profilin is a protein from the profilin family, which is a minor allergen of birch pollen.

Profilins can act as cross-reacting allergens, since they are detected in the pollen of various trees, meadow and weeds, as well as products of plant origin (vegetables, fruits, nuts, spices, latex). rBet v 4 - calcium binding protein polcalcin, a minor allergen of birch pollen, is detected in 10-20% of patients sensitized to birch pollen.

This allergen has a 67-90% similar structure to homologous proteins of timothy grass, pigweed, turnip, rapeseed, European olive, black alder and can serve as a marker of polyvalent sensitization to plant allergens. Determination of minor birch allergens rBetv 2, rBetv 4 IgE in the blood, the identification of which makes it possible to assess cross-reactivity with allergens of other plants and predict the effectiveness of allergen-specific immunotherapy.