From Big Medical Encyclopedia

DESENSITIZATION (grech, hypo-+ a sensitization) - 1) decrease in sensitivity of an organism to allergen; 2) a complex of the preventive actions lowering sensitivity of an organism to allergen by the prevention of development or braking immunol, mechanisms of a sensitization.

Depending on the applied means distinguish specific and nonspecific. The term «desensitization (specific and nonspecific)» is not recommended to be used since total disappearance of sensitivity of an organism to allergen practically does not come.

Specific desensitization

Specific desensitization — decrease in sensitivity of an organism to allergen by introduction to the patient of extract of that allergen, to Krom is available hypersensitivity. Specific G. is carried out at bronchial asthma, a small tortoiseshell, a pollinosis, an allergic rhinosinusopathy and other allergic reactions. This method was for the first time offered by L. Noon in 1911 for treatment of a pollinosis, and 10 years later is for the first time applied by V. Caulfield at bronchial asthma.

Specific G.'s mechanism is best of all studied at pollinosis (see). Most of researchers considers that at parenteral administration of allergens in an organism of the patient the blocking (protective) antibodies opened by R. Cook in the 30th are formed. These antibodies have big affinity to offending allergens, than reagins — the kozhnosensibiliziruyushchy antibodies responsible for development of allergic reaction of immediate type (see. Antibodies , allergic antibodies).

At hit of offending allergens in an organism through respiratory tracts (e.g., at a pollinosis, bronchial asthma) antibodies «block» them, and thus development of allergic reaction is prevented. Decrease in credits of reagins occurs only after long (within several years) specific G. Yu. A. Samushiya and S. A. Dakhil (1971) at the specific G. which is carried out by 102 sick pollinosis revealed blocking antibodies at excellent a wedge, effect in 80% of cases, at good — in 76%, satisfactory — in 33% and at absence a wedge, effect — only in 25%. They noted also accurate dependence between extent of decrease in a caption of reagins and duration specific. The same patterns concerning credits of the general and specific IgE noted with the help radioallergosorbent method (see) Anfosso-Capra, Vervloe (F. Anfosso-Capra, D. Vervloet, 1974), etc.

Thus, specific G. at allergic diseases it is possible to reach only full or partial a wedge, effect, and direct and indirect tests with offending allergen remain positive, but in smaller credits. Specific G.'s mechanism at an atopic form of bronchial asthma and other atopic diseases (see. Atopy ), apparently, the same, as at a pollinosis; specific G.'s mechanism is still insufficiently studied by bacterial allergens.

Specific G. is carried out only by allergologists after careful specific diagnosis of an allergic disease (the allergological anamnesis, skin, provocative tests and in vitro tests with noninfectious and infectious allergens). It is shown in all cases when it is impossible to stop contact with the revealed allergen: at an allergy to house dust, pollen of plants, a bacterial allergy; the patient having anaphylactic reactions to stings of bees and wasps in the anamnesis — as the only effective method of prevention of an acute anaphylaxis; at a medicinal allergy — only in those rather exceptional cases when the drug causing an allergy is vital to the patient (e.g., insulin at a diabetes mellitus); at food allergy — when the exception of a food-borne allergen (e.g., cow's milk at children) is extremely difficult. At an epidermal allergy specific G. is shown only when the termination of contact with animals is connected with change of a profession of the patient (to livestock specialists, veterinarians, laboratory assistants with a long standing of work).

Specific G. can be combined using antihistaminic drugs, dinatrium of a hromoglikat (intal), bronchial spasmolytics, sedatives. At the same time use of drugs of glucocorticoid hormones is not recommended, and carrying out preventive inoculations against infectious diseases is possible only in exceptional cases.

Specific G. at atopic diseases (a pollinosis, atopic bronchial asthma, an allergic rhinosinusopathy and a small tortoiseshell) is carried out in our country by the domestic standard pollen, epidermal, dust and food-borne allergens (serial production) containing from 10 000 to 20 000 PNU allergen in 1 ml of drug. The patient with anaphylactic reactions to stings of insects treatment is carried out by the allergens prepared from wasps and bees by a special technique (see Allergens as drugs). At an allergy to insulin specific G. is carried out by subcutaneous injections of cultivations of this drug. Allergens enter, as a rule, subcutaneously in the increasing doses and concentration. Initial concentration of allergen at a pollinosis and other atopic diseases is determined by way of intradermal allergometrichesky titration (see) a number of its tenfold cultivations (10 - 7 , 10 - 6 etc.). It is necessary to begin treatment with that concentration of allergen, edges the first caused slabopolozhitelny (+) intradermal reaction of immediate type.

Depending on an etiology of an atopic disease carry out early, year-round and seasonal specific G. by the listed above allergens.

Early G. is often applied at a pollinosis and always at allergic reactions to stings of insects. It is possible to begin right after disappearance from the environment of offending allergens (e.g., pollen of plants), but not later than in 2 months prior to the period of their emergence. Sometimes early G. of a pollinosis is carried out by endonasal administration of offending allergen in the increasing concentration. Vortmann (F. Wortmann, 1969) at a pollinosis at children gained good effect at the purpose of per os of bee honey and various aromatic sugars containing 10% of dry pollen.

Year-round specific G. is applied often at dust bronchial asthma. Twice a week do an injection of dust allergens before achievement of the most optimum dose for each patient, and then pass to a maintenance therapy, at a cut enter this dose of allergen 1 time into 1 — 2 week within 3 — 5 years. Sometimes year-round specific G. is carried out at a pollinosis, and offending pollen allergen is entered also into a blooming period of plants, but in a smaller dose.

More rare at dust bronchial asthma and a pollinosis carry out treatment in an allergological hospital by the accelerated method when injections of dust or pollen allergens do daily (or twice a day) before achievement of the most optimum and well transferable dose for each patient (during 3 — 4 weeks) with a break in 5 — 6 months.

Seasonal G. is carried sometimes out at a pollinosis to a blooming period of plants and a wedge, displays of a disease. Offending pollen allergen in small concentration and doses enter to the patient, napr, method «skin squares», Blamutye and Giber offered in 1959 Mr. (R. Blamoutier, L. Guibert): on skin of an inner surface of a forearm do a scarifying grid 10 cm long and 5 cm wide, an interval between scarifying lines of 5 mm; apply 0,2 ml of offending allergen on this grid. Seasonal G. is less effective, than early and year-round.

Specific G.'s method standard allergens at a pollinosis, atopic bronchial asthma and anaphylactic reactions to stings of insects gives a high wedge, effect (75 — 90%), however a shortcoming it is duration of treatment and a large number of injections. For reduction of number of injections of allergens at specific G. Volfromm (R. Wolfromm, 1959) with soavt, suggested to enter at the same time with offending standard allergen 0,1 ml of 0,2% of gel of aluminum hydroxide for the purpose of creation in an organism of depot of allergen. Injections do according to the shortened scheme once a week (0,2 — 0,8 ml of allergen in each cultivation instead of 0,1 — 0,2 — 0,4 — 0,8 ml). The number of injections at specific G. can be reduced also by use of the piridinovo-hydrocarbonate allergens adsorbed by aluminum hydroxide. This drug under the name allpirat is offered by Fuchs and Strauss (A. Fuchs, M. V. to Strauss) in 1959. For reduction of number of injections of allergens at a pollinosis abroad use also the allergens deposited by means of tyrosine.

Specific G. at an infectious and allergic form of bronchial asthma, preasthma and urticaria (a bacterial origin) is carried out in our country by means of standard microbic allergens.

At infectious and allergic bronchial asthma and preasthma use also the drugs containing not only microbic cells, but also their ekzoprodukta — toxins, enzymes. In the USSR Academy of Medical Sciences Research Allergological Laboratory (RAL) methods of specific diagnosis and specific G. at an infectious and allergic form of bronchial asthma and preasthma are developed by the microbic vaccines prepared on the platelets covered with cellophane disks (automono-and heteromonovalent vaccines). Take smears from a mucous membrane of a nose, a pharynx, bronchial tubes from the patient (at a bronkhoskopiya). From everyone sowed from a sick microbic strain (pathogenic, conditionally pathogenic, saprophytic) prepare the automonovaktsina containing 1 billion microbic bodies in 1 ml. For specific G. use set automono-or the heteromonovalent vaccines which caused positive reaction to intradermal and inhalation provocative tests (usually slowed down type). Initial concentration of standard microbic allergens is defined by allergometrichesky intradermal titration of offending allergen, initial concentration microbic auto-and the heterovaccines prepared on cellophane disks is defined by intradermal titration of the monovalent vaccines containing various number of microbic bodies (1000, 10 000, 100 000 etc.) in 1 ml of drug. Begin treatment with introduction of 0,1 ml of drug of that concentration, edges caused slabopolozhitelny (+) or doubtful (+) reaction of the slowed-down type at intradermal introduction. Standard microbic allergens and vaccines enter subcutaneously, less often vnutrikozhno more often. Injections do twice a week in the increasing doses and concentration before achievement of a dose, optimum for each patient, then pass to a maintenance therapy, at a cut enter the same dose of drug weekly (or 1 time in 10 days) for 3 — 5 years.

Complications. On site administrations of allergen or a vaccine there can be a local reaction in the form of pruritic painful infiltrate. In such cases the interval between injections is extended and repeatedly several times enter that dose of allergen (or vaccines), edge did not cause the expressed local reaction.

At bystry increase in a dose of allergen (or vaccines), reduction of an interval between injections, and also introduction of a bigger dose of allergen system reactions (urticaria, allergic conjunctivitis, rhinitis, an attack of bronchial asthma) are possible. According to NIAL USSR Academy of Medical Sciences, at specific G. system reactions (most often attacks of suffocation of various degree) are noted by microbic vaccines of patients with an infectious and allergic form of bronchial asthma at 38% of patients. Sometimes there are aggravations in the centers hron, infections. In these cases it is necessary to stop vaccinotherapy and to carry out the corresponding treatment (antibacterial therapy). System reactions at treatment of atopic diseases develop usually within 40 min. after an injection of allergen and quickly take place after use of antihistaminic drugs or a subcutaneous injection of 0,1% of solution of adrenaline. If the patient was timely not given help, at it can develop acute anaphylaxis (see). Therefore within 40 min. after an injection of offending allergen of the patient shall be under observation of the doctor. Can be the reasons of an acute anaphylaxis also administration of allergen in the dose and concentration exceeding ordered by the doctor; hit of allergen directly in a vessel (it is necessary after introduction of a needle under skin to pull the piston of the syringe on itself; if in the syringe there is blood, it is necessary to take out a needle and to make an injection to other place); increase in a dose of allergen to the patient, at to-rogo later introduction previous, smaller, doses urticaria, an itch a century, cough, cold was noted.

At the first symptoms of an acute anaphylaxis the patient needs to enter urgently subcutaneously adrenaline, Cordiaminum, caffeine, antihistaminic drugs, glucocorticoid hormones, cardiac glycosides, an Euphyllinum (intravenously), oxygen; at indications hold resuscitation events (see Resuscitation). After removal from an acute anaphylaxis each patient is subject to hospitalization for observation, inspection and the corresponding therapy (cardiovascular, antihistaminic and glucocorticoid drugs for the purpose of prevention of late complications of an acute anaphylaxis — allergic myocarditis, nephrite, hepatitis, etc.).

At specific G. the acute anaphylaxis is not observed by microbic vaccines and bacterial allergens.

Contraindications: an aggravation of a basic disease, heavy organic changes of lungs at bronchial asthma with hron, pulmonary and a pulmonary heart, prolonged treatment by glucocorticoid drugs, pregnancy, and also the following diseases; rheumatism in an active phase, tuberculosis of any localization in an active phase and others hron, infectious diseases in stages of an aggravation, malignant new growths, dekompensirovanny cardiovascular diseases, diseases of blood, a dekompensirovanny diabetes mellitus and other diseases of endocrine system (except for patients with an allergy to insulin), collagenoses, mental diseases in a phase of an aggravation, a peptic ulcer of a stomach and duodenum in a phase of an aggravation, acute infectious diseases.

Nonspecific desensitization

Nonspecific desensitization — decrease in sensitivity of an organism to allergen under the influence of some medicines, separate types of a physiotherapeutic and resort therapy. Apply it when specific G. is impossible or insufficiently effective, and also at a sensitization to substances of the obscure nature. Quite often nonspecific G. is applied in a combination to specific. Nonspecific G. — one of types of treatment of allergic diseases directed to the prevention of development or braking immunol, mechanisms of a sensitization (therefore use of antihistaminic drugs, dinatrium of a hromoglikat, stimulators of beta and adrenergic receptors, etc. is not nonspecific G.).

Resort factors have the expressed hyposensibilizing effect. Under their influence degree of specific sensitivity to allergen decreases (by results of allergometrichesky titration after stay of patients in the Kislovodsk resort); the combination of resort factors to specific G. gives more expressed clinical effect.

Variation and constant magnetic field of strictly certain parameters possesses the hyposensibilizing action. Drugs of glucocorticoid hormones in small doses raise a threshold dose of allergen, can «start» edges immunol, mechanisms of a sensitization. In high doses they suppress development of an immune phase, slowing down phagocytosis and digestion of allergen in phagocytes, destroying small lymphocytes and oppressing synthesis of antibodies. Glucocorticoids participate also in braking by patokhy. and patofiziol, phases of allergic process.

It is possible to carry immunodepressants to group of the hyposensibilizing means (see. Immunodepressive substances ), however their use is limited to strictly certain framework. A hyposensitizing effect also some other remedies — a blood plasma, drugs of calcium, sodium hyposulphite, etc. possesses, but the exact mechanism of their action remains still insufficiently clear.

See also Sensitization .

Bibliography: Allergic diseases At children, under the editorship of M. Ya. Studenikin and T. S. Sokolova, page 331, M., 1971; Artaud-masova A. V. Clinic, diagnosis and therapy of allergic reactions on sting of bees and wasps, Klin, medical, t. 51, No. 5, page 61, 1973, bibliogr.; Beklemishev N. D. idr. Pollinoses (hay katara), page 142, Alma-Ata, 1974; Gudkova R. G. About the specific desensibilizing therapy of bronchial asthma, Klin, medical, t. 45, No. 5, page 55, 1967, bibliogr.; With and m at sh and I am Yu. A. both D ah and l S. A. O of a role of blocking antibodies at specific desensitization of pollinoses, in book: Probl, allergol., under the editorship of A. D. Ado and A. A. Podkolzin, page 184, M., 1971; Sidorenko B. N. Specific desensitization at bronchial asthma of the infectious nature, in book: Bronchial asthma, under the editorship of A. D. Ado and P. K. Bulatova, page 274, M., 1969; A n f about s s o-S a p r a F. and. lake of Evolution of reaginic antibodies in specific hyposensitization, Acta allerg. (Kbh.), v. 29r p. 79, 1974; Blamoutier P., Blamoutier J. et Guibert L. Traitement de la pollinose avec extraits de pollens par la of m£thode des quadrillages cutanes, Presse m6d., t. 67, p. 2299, 1959; Fuchs A. M. a. Strauss M. B. The clinical evaluation and the preparation and standartization of suspensions of a new water-insoluble whole ragweed pollen complex, J. Allergy, v. 30, p. 66, 1959; M i 1-ler A. S. M. a. Tees E. C. A metabolizable adjuvant, clinical trial of grass pollen-tyrosine adsorbate, Clin. Allergy, v. 4, p. 49, 1974; W o 1 f r o m m R. e. a. D6sen-sibilisation par association of extemporan£e d’hydroxyde d’alumine aux of allerg£nes (allergfcnes h action retard), Acta allerg. <Kbh.), t. 24, p. 202, 1969; WortmannF, £>6 of sensibilisation sp6cifique des pollinoses par voie orale chez les enfants k 1'aide de pollen en poudre, Rev. franc. Allerg., JMs 3, p. 195, 1969.

Yu. A. Poroshina, A. I. Ostroumov; B. I. Pytsky (desensitization nonspecific).