18 November 2022

Sneezing on allergies

How does allergovaccina work

Olga Hardina, "The Snob"

Allergen-specific immunotherapy (ASIT) is so far the only way to cure allergies, and not just relieve symptoms. The method is more than a hundred years old, but not everyone still knows about it, and those who know are often afraid of interfering with the immune system. We understand how ASIT works.

Bug in the system: what is an allergy?

Allergy is an error of the immune system, in which the body takes harmless substances for harmful and begins to fight them. Most often, the reaction occurs to plant pollen, food, animal allergens and mold. There is an opinion that allergies used to be a rarity. That's not so. Avicenna and Galen also wrote about the "spring cold"; judging by the memoirs of contemporaries, Napoleon Bonaparte suffered from an allergy to pollen, whose runny nose greatly spoiled his life in the summer of 1812. Lacrimation, sneezing, snot, allergic conjunctivitis are not the only consequences of allergies. If contact with the allergen persists, symptoms may worsen over the years, up to a constant narrowing and swelling of the respiratory tract — bronchial asthma.

Vaccine against cats and birches

At the beginning of the XX century, vaccination was gaining momentum. Medical scientists thought: what if we vaccinate people not only from dangerous viruses, but also from pollen? Microbiologists Leonard Noon and John Freeman subcutaneously injected patients with aqueous plant extracts, achieving the formation of immunity. It worked: in three years, 82 out of 84 patients had reduced allergy symptoms, a third of them completely disappeared for a while. This treatment became the prototype of ASIT — allergen-specific immunotherapy. 

Over the next hundred years, new allergens were discovered, drug dosages and intake regimens were verified. In the 1960s, ASIT began to be made in the USSR. Allergovaccines from house dust mites, birch pollen, ragweed and timothy grass are now registered in our country.

The essence of ASIT is as follows, explains Anna Kosova, allergist—immunologist at the Lahta Clinic: "We give a person an allergen in a verified dose, increase it and stimulate the immune response - the one we need and which will protect the body. And then, in a real collision with an allergen, an excessive reaction will no longer occur."

Treatment regimen

First you need to identify a specific allergen. The brighter the reaction, the better for diagnosis and treatment success. Usually everything is clear from the anamnesis, it remains only to confirm the sensitivity to the allergen with the help of skin tests or analysis for IgE antibodies to a particular protein. Sometimes there are doubts about which allergen is more significant — dust mites or cat hair, an allergen of birch or meadow grasses. Then the doctor will prescribe additional tests that will show which allergen molecule a person is sensitive to. It depends on whether ASIT will be successful.

When to be treated?

In the case of pollinosis, treatment begins four months before the flowering season: if it is allergic to birch pollen — in January, if it is meadow grass — in February. The therapy lasts five to six months, and the cycle repeats the next year. And so for three to five years in a row. If you are allergic to dust mites, a person should take medications constantly, and you can start treatment at any time when there is no exacerbation.

How to take it?

Preparations for ASIT are produced in the form of injections, drops or tablets. Drops and tablets should be drunk every day; injections are made strictly in the clinic under the supervision of a doctor at intervals of several days to several weeks.

How long will it last?

According to Anna Kosova, on average, the effect appears after four to six months and lasts for ten years or more if a person has completed a full course. If symptoms return, treatment can be repeated. However, during remission, an allergy to something else may well develop. "I have been allergic to household dust since childhood, I have already passed ASIT twice. And now, it seems, new allergens have appeared: in the spring I was covered in snot, although I did not react to flowering before," says Natalia S. from Moscow. This does not mean that after ASIT, the allergy "spread" to something else: most likely, a reaction to flowering would have occurred anyway. This can happen in any person at any age, but allergy sufferers have a higher risk of new reactions.

How much is it? 

The cost of drugs for one month is 7-8 thousand rubles. You may additionally have to take a test to determine the allergen, which will cost from 2.5 to 25 thousand rubles, depending on the number of allergens being determined. It is also worth considering visits to an allergist: two at the start of therapy and one during the flowering season. In case of CHI treatment, doctor's visits will be free of charge.

Security issues

Many are afraid that ASIT interferes with the immune system — suddenly something will break there. These fears are unjustified: the reaction changes to just one protein-allergen. If earlier, when confronted with it, the body produced IgE antibodies, which triggered a cascade of unpleasant symptoms, then the production of IgG antibodies is stimulated with ASIT. They block the action of IgE and form long-term resistance to the allergen.

Another fear concerns the possibility of anaphylactic shock when taking the drug. In total, several cases of such a reaction are known among millions of patients over the decades, and drops and tablets are safer than injections — no fatal reactions have been registered at all. Treatment is also allowed for children from the age of five. "We did ASIT for my son from the age of five, the treatment lasted three years in a row. At first, there might be redness around the mouth, then we reduced the dosage. If the cough worsened, they gave an antihistamine," says Ksenia T. Of course, ASIT has contraindications: for example, with uncontrolled asthma and chronic diseases, if they are not stopped by appropriate drugs.

"We tell anxious patients: ASIT is an additional, not mandatory treatment. We can only recommend it so that a person does not live for decades on antihistamines and reduces the risk of developing asthma," explains Anna Kosova.

Well, in the meantime, some are afraid of side effects, others are looking forward to the registration in Russia of allergovaccin for pet lovers — drugs, unlike hypoallergenic cats, already exist and are successfully used in the West.

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