Specific and nonspecific hyposensitization
Last reviewed: 23.04.2024
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Specific hyposensitization (or specific immunotherapy) - the creation of resistance to the action of the allergen responsible for hypersensitivity, by the preventive administration of this allergen in gradually and strictly individually increased doses, starting with subthreshold.
[Indications for the procedure
The method of specific hyposensitization (immunotherapy) is applied when it is impossible to completely stop contact with an etiologically significant allergen (for example, in patients with sensitization to house dust, pollen of plants, mold fungi, bacterial allergens, etc.).
Technique of the hyposensitization
Begin the introduction of the allergen from a very small dose (1: 1.000.000 - 0.1 ml), then the dose is gradually increased.
Mechanism of action:
- formation of blocking antibodies IgG;
- reduction of IgE synthesis;
- induction of T-suppressors;
- activation of polymorphonuclear leukocytes;
- increased phagocytosis;
- decreased sensitivity of target cells to allergic reactions to allergens and mediators of allergy;
- development of immunological tolerance;
- increased levels of IgA in bronchial mucus;
- stabilization of membranes of mast cells.
The allergens used for specific immunotherapy can be of various types (water-salt, purified allergens, active allergen fractions, chemical modified allergens, enhanced immunogenic and attenuated allergenic properties, prolonged allergens).
Specific immunotherapy gives a positive therapeutic effect in pollen bronchial asthma - in 70% of patients, with domestic bronchial asthma - in 80-95% with a disease duration of less than 8 years.
Patients with pollen bronchial asthma are preseasonally treated.
A. Ostroumov (1979) showed the high efficiency of specific immunotherapy with the use of purified allergen from ragweed pollen. Cleared allergens are better tolerated. S. Titova has developed a technology for the production of zincanthal, a purified, sorbed, prolonged drug. There are no side effects, which is due to the lack of ballast substances.
In recent years, directed chemically modified therapeutic allergens are being created:
- allergoids are formatted allergens;
- tolerogens are allergens denatured with urea.
These drugs cause persistent suppression of IgE antibodies, stimulate the formation of IgG antibodies. They have low allergenicity and high immunogenicity.
The experimental study of allergovaccine is also completed. Allergovakciny - a complex of purified allergens with synthetic polymers carriers. Such drugs inhibit the formation of allergic reactants (IgE antibodies), but enhance the synthesis of blocking IgG antibodies. (A complex of pollen allergen timothy and a synthetic polymer polyoxidonium).
In recent years, a new direction of specific immunotherapy has been used - the use of immune complexes consisting of allergens (tick-borne and pollen) and specific autologous antibodies for treatment. In the process of treatment, the titer of anti-idiotypic immunoglobulins increases. The method is safe, it is possible to reduce the dose of the administered allergen.
Contraindications to the procedure
Contraindications to specific immunotherapy:
- exacerbation of bronchial asthma and chronic foci of infection;
- exacerbation of concomitant diseases - diabetes, kidney disease, liver, hypertension, coronary heart disease, toxic goiter, blood diseases, systemic connective tissue diseases, other allergic diseases;
- the presence of irreversible changes in pulmonary tissue (emphysema, pneumosclerosis), respiratory or heart failure;
- long-term therapy with glucocorticoids;
- mental illness;
- oncological diseases;
- pregnancy and lactation;
- active phase of rheumatism.
Nonspecific desensitization
Nonspecific desensitization is the use of drugs and methods that reduce hypersensitivity to different (not necessarily specific) antigens-allergens.
The methods of nonspecific hyposensitization include:
- RDT (unloading-dietary therapy);
- treatment with histaglobulin, allergoglobulin;
- treatment adaptogeneens.