Timothy grass rPhl p 7, rPhl p 12 IgE, g214

A new direction has appeared in the diagnosis of allergic reactions: Molecular diagnostics of allergy is a component allergodiagnostic. Molecular allergy diagnosis is based on the detection of sensitization to allergens at the molecular level using natural highly purified and recombinant allergen molecules, i.e. their components rather than extracts.

In the late 1980s, when the introduction of NK technologies began, it was possible to characterize and clone allergen molecules, which helped to identify antigenic determinants in various allergic diseases. All this played an important role in the emergence of a new type of diagnosis – molecular diagnostics, which, in turn, contributed to the development of more effective allergy treatment. The 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 between true and cross-allergy.

The use of recombinant allergens is a new tool in the diagnosis of type I allergic reactions, which allows you to obtain detailed information on patient sensitization, cross-reactivity with other allergens, justify the feasibility and predict the effectiveness of allergen-specific immunotherapy (ASIT). This direction will change the views on the examination and treatment of patients and bring them in line with those in world medicine. There are 3 main advantages of doing this analysis:

Molecular allergodiagnostics, which makes it possible to differentiate true sensitization from sensitization due to cross-reactivity. These data will help identify the sources of allergies: a single one, several closely related ones, or many different ones.
Molecular allergodiagnostics will eliminate the need for provocative tests and allow you to give clearer recommendations regarding the elimination of contact with allergens.
Molecular allergodiagnostics 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 is shown that the use of molecular diagnostic methods makes it necessary to change the ASIT, selected according to the results of skin prick tests.

In order to start using allergen components and correctly interpret analysis results, it is necessary to know basic information about allergen components and their clinical application:

Allergen molecules are given a name, at the beginning the first three letters of the Latin genus name, then the first letter of the species and the 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 allergenic substance contains not one but several protein components that can act as allergens: "major" - main allergens, others "minor" - secondary allergens. Major allergen components are such allergenic molecules, antibodies to which are found in more than half – 50% of patients in the population responding to this source. They are resistant to heat and more immunogenic. They are large in size and are contained in this allergen in larger quantities. Minor ones are smaller in size and less immunogenic allergenic molecules that are usually contained in smaller amounts 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 allergens and less than 10% are called minor allergens.

The culprits of allergies include herbs and trees. One of the representatives of herbs is timothy grass. Timothy grass (lat. name Phleum pratense) refers to grasses of the cereal family, widely distributed throughout the world. Timothy grass is a hardy plant and begins to bloom in early spring. Pollen of Timothy's grass may be the cause of allergic diseases. Symptoms of allergic reactions to timothy pollen manifest themselves in the form of redness and burning of the mucous membrane of the eyes, watery eyes, blepharoedema, nasal congestion, sneezing, coughing, shortness of breath and bronchospasm.

To determine sensitization to timothy grass as a complex allergen, the following are investigated:

Phl p 1 and Phl p 5b are the main "major" allergens, Phl p 7 and Phl p 12 are minor "secondary" ones.
Phl p 1 is a glycosylated protein, the main ("major") allergen of timothy, specific IgE antibodies to which are detected in 95% of patients with allergies to pollen of various types of meadow grasses.
Phl p 5b is the main and one of the most reactive allergens of timothy, which provokes symptoms of allergic rhinitis and bronchial asthma in sensitized patients. IgE antibodies to this allergen are detected in 65-90% of people with allergies to meadow grass pollen.
Phl p 7 is a calcium-binding protein, a minor allergen of Timothy pollen. It is detected in 10-15% of patients sensitized to meadow grass pollen and causes cross-reactivity with many plants (birch, alder, olive, weeds and others).
Phl p 12 is a protein from the profilin group, a minor allergen of timothy. Antibodies of the IgE class are detected in 15-30% of patients with allergy to meadow grass pollen. Timothy profilin proteins have a similar structure to the profilins of many plant species, food products of plant origin and latex.

The true allergy to timothy pollen is confirmed by the presence in the blood of specific IgE antibodies to the main allergen components Phl p 1, Phl p 5b, and the presence of reagin antibodies only to secondary ("minor") allergen components (Phl p 7, Phl p 12) indicates cross-sensitization with other plant allergens.