Birch rBet v 1 PR-10 IgE, t215
Allergen component diagnostics is based on identifying sensitization to allergens at the molecular level using natural highly purified and recombinant allergen molecules, i.e., their individual allergen components.
There are three main advantages to performing this analysis:
- Allergen component diagnosis makes it possible to differentiate between true sensitization and sensitization due to cross-reactivity. This data will help identify the sources of allergies: a single source, several closely related sources, or many different sources.
- Molecular allergy diagnostics eliminates the need for provocation tests and allows for more precise recommendations regarding the elimination of contact with allergens.
- Molecular allergy diagnostics is necessary in the selection of ASIT, in individuals with polyvalent (multiple) sensitization, to determine the most important allergen for which therapy will be carried out in the most accurate way.
The allergenic substance consists of not one, but several protein components that can act as allergens:
- Major allergenic components are the main allergenic molecules, antibodies to which are found in more than half (50%) of patients in the population who react to a given source. They are resistant to heating and more immunogenic. They are large in dimension and are contained in this allergen in larger quantities.
- Minor allergens are secondary, smaller in dimension and less immunogenic allergenic molecules, which are usually present in smaller quantities within an allergen, but are found in many different allergens, sometimes not closely related, causing cross-allergy. That is, allergens with a prevalence of more than 50% are called major, and less than 10% are called minor.
Grasses and trees can be considered the culprits of allergies. One of the representatives of trees is birch (Latin name Bétula).
Allergy to birch occurs in late April – early May, during the flowering period of this tree. Most often, allergy to birch pollen manifests itself as pollinosis (hay fever) and allergic conjunctivitis with their characteristic symptoms:
- nasal congestion, runny nose,
- clear nasal discharge,
- itchy nose,
- sneezing "in bursts"
- swelling and itching of the eyes,
- watery eyes.
In more rare cases, skin reactions (allergic urticaria) and symptoms of intoxication (lethargy, rapid 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 tested:
- rBet v 1 PR-10 IgE is the main "major" allergen,
- rBet v 2 profilin and rBet v 4 are secondary "minor" allergens.
True allergy to birch pollen is confirmed by the presence of the major allergen rBet v 1 PR-10 IgE in the blood. rBet v 1 PR-10 IgE is detected in most patients sensitized to birch pollen. The structure of rBet v 1 PR-10 IgE is homologous to pollen proteins from other trees of the birch, beech, walnut families and taxonomically related fruits (apples, apricots, peaches, cherries), vegetables (carrots, celery) and spices. In addition to respiratory symptoms, local manifestations of allergy are observed when fruits, certain vegetables, and nuts are consumed, including oral allergy syndrome in the form of itching, burning, swelling, and redness in the mouth.
rBet v 2 profilin - a protein from the profilin family, which is a minor allergen in birch pollen. Profilins can act as cross-reactive allergens, as they are found in the pollen of various trees, meadow and weed grasses, as well as in 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 rBet v 2, rBet v 4 IgE in the blood allows assessing cross-reactivity with allergens of other plants and predicting the effectiveness of allergen-specific immunotherapy.