About the molecular diagnostics

Every year the allergic illnesses affect more and more of the world's population inflicting the unpleasant sensations which are gradually increasing to the conditions that are harmful to health. Until now, the diagnostics of allergic illnesses have been based on the patient's anamnesis, skin prick test results, allergen-specific IgE detection in blood serum, and clinical monitoring after the elimination of the allergen from the environment as well as (where possible) the provocative tests. Currently the quantitative tests of allergen-specific IgE determination have proven to be very useful for the optimal allergy diagnostics. In Sweden, since the year 2007 it has become possible to analyze the allergenic substances to the single sensitizing proteins (components of the allergens). This is called molecular allergology. These single proteins are named in accordance with the Latin name of their allergen origin (for example: peanut = Ara h aka Arachis hypogea) and are numbered according to the order of their discovery.
Today, the molecular allergology is applied in all Europe. During the Allergomedica program your sensitization to 38 allergens, which are commonly founded, is tested to the molecular level and is comprised from up to 147 components (allergen molecules).

Vilius and Antanas (these are not the real names of the patients) have decided to test their allergies through the comprehensive Allergomedica program of allergy diagnostics. After receiving the blood samples of both of the patients, the specialists of “Imunodiagnostika” laboratory have carried out a thorough diagnostics of allergies.

Comparison of the results of both patients revealed that after the performance of the ordinary 1st step of the diagnostics, the results are almost identical – both Vilius and Antanas are allergic to birch, timothy, cat, apple, and nuts (in the case of Vilius, the allergy is for two kinds of nuts, i.e. hazelnut and peanut and in the case of Antanas - hazelnut).

If at this step the diagnostic of allergy would be terminated, both patients would receive the same treatment and preventive measures; however, after the performance of the 2nd and 3rd steps of the Allergomedica diagnostics it have been revealed that the strong sensitization of Antanas to the hazelnut and apple allergen components is related to the sensitization to birch pollen. This means that Antanas does not have the allergy for hazelnut or apple and may experience the itching, tingling, and swelling of the oral mucosa only when eating the aforementioned products without the thermal processing (due to the similarity of these allergen components to the birch pollen to which the patient is allergic). After the treatment of allergy for birch, Antanas would no longer feel the symptoms caused by the hazelnut and apple.

Meanwhile, the test results of Vilius are showing the substantial sensitization to the component of the hazelnut which leads to the especially severe allergic reactions to hazelnuts; therefore, eating of these nuts, as well as the products containing them is strictly forbidden, inasmuch as it can lead to anaphylactic shock, which can result in death. In order to avoid serious consequences, it is recommended for Vilius to always have an adrenaline injection with himself.
Therefore, the testing of the patient’s sensitization to the molecular level is the necessary condition for the comprehensive diagnostics of the illness, as well as for the further evaluation of the course of the illness and precise recommendations.

Ideology of the molecular allergology:

  1. To detect the true allergen between the cross-reactive allergens.
  2. To acquire the knowledge regarding sensitizing components of the allergens, to evaluate their resistance to environmental factors (for example: heat), as well as the homology between the sensitizing component and other allergens. In consequence, to determine whether the patient is sensitized to the cross-reactive component of the allergen (the contact will cause only minimal clinical allergic phenomena) or to the component which is causing the “real” allergy (high possibility of systemic reactions).
  3. While having knowledge regarding which part of allergen is composed of the sensitizing component, to evaluate the strength of the immunological response while in contact with the allergen.

While testing the allergy for milk, egg, fish, pollen, domestic animals, and house dust mites we are aware that the higher the concentration of specific IgE for allergen in serum is detected, the higher the probability of experiencing allergic symptoms when contacting with the allergen. However, as regards the major part of allergens belonging to the products of plant origin (such as peanut, soybean, and wheat) this correlation is not clearly observable. This phenomena arises from the fact that the molecular components of the allergen existing in certain products have higher or lower homology regarding the proteins of other allergens. Such exposure can lead towards the determination of allergen specific IgE in blood serum even though the patient is not sensitized to the product.

The main component of the birch pollen allergen Bet v 1 is one of the clearest examples. This component of allergen belongs to the protein class PR-10 (pathogenesis-related proteins of class 10).

Allergenic components of the protein class PR-10 are found in the major part of the products of plant origin and are distinguished by the high homology with Bet v 1. In the allergen of the hazelnut the molecule belonging to the protein class PR-10 is called Cor a 1, in the allergen of the peanut - Ara h 8, soy – Gly m 4. These proteins are so similar to the main component of the birch pollen allergen that the cross-reactions between the aforementioned components and Bet v 1 are excessively frequent, especially when the sensitization to birch is high. The cross-reactions between the IgE antibodies against the structurally related molecules also means high possibility of the occurrence of the cross-reactions in the clinical practice. This is precisely why the persons sensitized to birch are feeling unpleasant symptoms in the oral and pharynx mucosa (such as itching or tingling) when eating the products of plant origin containing the protein class PR-10 (apple, hazelnut, peach, and etc.), even when they are not sensitized to the aforementioned products.

The patients, to whom the cross-reactions for the products occur due to the sensitization to birch pollen, are not considered to be in the group with the possibility of the severe systemic reactions (eg. anaphylactic shock) arising from the products. This is determined by the reason that the proteins of the class PR-10 are unstable in the products and sensitive to the factors such as: thermal processing of the products, digestive enzymes, and extreme pH changes in the gastrointestinal tract.

It is important to note that the low possibility of the severe allergic reactions relates only to symptoms occurring due to the cross-reactions. Sensitization to the specific component of the product (for example: to the specific component of the hazelnut Cor a 14) can result in extremely severe, life-threatening conditions.

Quite often a mixed sensitization occur among the patients, i.e. the sensitization to the non-specific component of the product due to the cross-reaction, as well as the sensitization to the specific component of the product. Due to this reason, the testing of the patient’s sensitization to the molecular level is a necessary condition for the comprehensive diagnostics of the illness, as well as for the evaluation of the further course of the illness and precise recommendations.

Cross-reactions also occur between the allergens of the same class (for example: between the pollen of the different trees, different domestic animals, insects, latex, allergens from the animal products, containing tropomyosin, and etc.). The determination of the sensitization to the specific component of the allergens enables the identification of the “real” sensitizing allergens and allows not only to clarify the real diagnosis of the patient, to provide the exact lifestyle recommendations, but also to apply the appropriate immunotherapy treatment.

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