Allergy and immunology

Nowadays, the word “allergy” is well known, denoting an increased sensitivity of the body to the effects of certain environmental factors. And probably every reader will be able to recall many examples of the manifestation of an allergic reaction from the experience of his own life or from the stories of relatives, acquaintances, colleagues.

Allergy often manifests itself during the flowering of herbs, during contact with pets or inhalation of fumes of coloring substances. An allergic reaction can be caused by medications and even ordinary dust. Sometimes certain foods, synthetic compounds, chemical detergents, cosmetics are intolerable… It is difficult to count all possible allergens, of which more and more are revealed over time.

Allergens include both substances that have a direct allergenic effect and substances that can strongly potentiate the action of other allergens.

Different people, due to the genetic characteristics of the immune system, have different reactivity towards different groups of allergens.

Main types

  • Dust and house dust mites
  • Foreign proteins contained in donor plasma and vaccines
  • Pollen of plants (pollinosis)
  • Mold fungi

Medicinal preparations:

  • Penicillins
  • Sulfonamides
  • Salicylates
  • Local anesthetics

Food products:

  • Nuts
  • Sesame seeds
  • Seafood

Legume Eggs

  • Milk
  • Cereals
  • Citrus fruits
  • Honey

Insect/arthropod bites:

  • Bee Venom
  • Wasp Venom

Animal Products:

  • Animal hair
  • Cockroaches
  • Discharge of a domestic tick


  • Latex
  • Nickel Compounds
  • Chemical cleaning products (washing powder, dishwashing liquids, etc.).

Allergic diseases have existed since ancient times. So, mentions of the conditions caused by them are already found in the famous ancient Greek physician Hippocrates, who lived in the V-IV centuries BC. One of the manifestations of allergy, acute urticaria, was described by the ancient Roman healer Galen (II century AD).


Allergies become especially dangerous due to environmental pollution. It affects an increasing number of people in different parts of the world.Our four-legged pets are also susceptible to allergies. Some of them do not tolerate any food products, exposure to household chemicals and even communication with their owners (it is no secret that not only animals can cause an allergic reaction in humans, but also humans in animals).

Characteristic signs of allergy are redness of the skin and rash, inflammation of the mucous membranes (in particular, the appearance of a runny nose and tears), swelling, suffocation, coughing attacks. The rhythm of the heartbeat may be disturbed and a general malaise may develop. In some cases, edema (for example, larynx, lungs) is life-threatening. Allergy-induced anaphylactic shock can also lead to a fatal outcome.Already in the Middle Ages, a famous healer advised an allergic person who turned to him to replace a feather bed with a simple canvas bedding. The result was not slow to affect – the manifestations of the disease caused by dust accumulated in the feathers stopped.

Such manifestations of the body’s reaction to certain substances have been known for a long time. Not yet knowing the underlying causes and mechanisms of its action, professional doctors and folk healers sought to alleviate the condition of the suffering, to make the disease recede. Sometimes it was very successful.

Allergy remedies are included in the arsenal of traditional medicine. Moreover, restorative medicinal fees, which help to increase the body’s resistance to harmful effects, sometimes turn out to be very effective.

But still, non-traditional methods (including herbal medicine and diet) are auxiliary in the fight against allergies, while the main role is given to traditional medicine.

However, in order to successfully combat the disease, it is necessary to thoroughly understand the mechanism of its occurrence. This will certainly help prevent the disease. Now medical science has developed these problems in sufficient depth, which allows us to consider them in detail.

One of the most important factors on which the manifestation of an allergic reaction depends is the immune system. The latter is designed to protect the body from elements that can have a harmful effect on it. The danger can come from microbes, foreign proteins, various chemicals and even from the body’s own cells, if they tend to degenerate into malignant cells that develop into cancerous tumors.

Elements that interfere with the normal functioning of the body, carrying a certain danger to its existence, are commonly called antigens. These can be various enzymes, toxins, foreign proteins and other substances that enter the body with microbes, plant pollen, medicines, in particular serums.

Special blood proteins, antibodies, otherwise called immunoglobulins, come into opposition with antigens. They are produced by some cells of the lymphatic system in the presence of antigens.

Immunoglobulins are highly sensitive to the presence of foreign substances. They are designed to bind and block antigen cells. And subsequently, together with them, they are destroyed by special cells (phagocytes) and are excreted from the body.

During the interaction of antigens and antibodies, substances that have a negative effect on the body can be produced. They play a crucial role in the occurrence of allergic reactions.

Usually, the body secretes the necessary amount of antibodies to fight antigens. But if, for some reason, the immune system malfunctions and produces a larger number of immunoglobulins than necessary, the latter can have a destructive effect on the body, causing allergic reactions that are dangerous to health and even to life itself.

It happens that antibodies “by mistake” begin to attack kidney tissues or red blood cells of their own body, reacting to them as foreign harmful substances.

An inadequate response of the body to the effects of foreign substances is called an allergy. This word in Greek means “another reaction” (from “allos” – “other” and “ergon” – “action”).

Certain types of antibodies counteract various antigens. There are only five classes of immunoglobulins, each of which must protect the body from certain antigens.

Allergy class A includes immunoglobulins that counteract various harmful microbes, toxins, viruses and protect mainly the mucous membranes. This type of antibodies also includes those that play an important role in the body’s response to cold and in protecting against certain allergens. In turn, class A immunoglobulins are involved in the mechanism of occurrence of rheumatic allergic diseases.

Class D is represented by immunoglobulins released during inflammation of the bone marrow, i.e. osteomyelitis, and involved in a number of skin allergic reactions.

The most common immunoglobulins belong to class G. Within this group, there are several types of antibodies designed to fight certain types of toxins, microbes and viruses.

However, immunoglobulins of this class themselves can cause a number of severe allergic diseases. In particular, hemolytic disease of infants (developing due to the production of antibodies in the mother’s blood to the Rh factor present in the fetal blood), neurodermatitis, eczema and some others.

The most active immunoglobulins in the processes of allergy development belong to class E. They are the first to react to the appearance of allergens, although they do not directly participate in their destruction. They also contribute to the formation of a special allergic mood of the immune system.

The content of antibodies of this type in the body depends, in particular, on age – the largest number of them is produced by 7-14 years of life.The presence of a more or less significant proportion of Class E immunoglobulins also varies depending on the geographical location and climatic conditions of the country in which a person lives.

Another class of immunoglobulins is designated by the Latin letter M. These antibodies are involved in the fight against intestinal infections and rheumatic diseases. They bind bacteria that enter the body, destroy red blood cells of incompatible blood groups.

Due to the higher content of class E immunoglobulins in the blood, Ethiopian residents are more prone to allergic diseases than Scandinavians.The immunoglobulins of these five classes differ from each other not only in their role in resisting antigens, but also in their molecular weight and specific proportion in the total number of antibodies.

In the process of recognition and destruction of foreign cells, various immune system cells are involved in their functions, which are scattered throughout the body. They are called lymphocytes and are formed through the transformation of stem cells.

The task of antigen recognition is assigned to those cells that are the first to come into contact with foreign elements. These are macrophages and monocytes, as well as some cells of the liver and nervous system.

Then lymphocytes act against the antigens. They, in turn, are divided into several categories depending on the functions performed. Part of the lymphocytes is involved in blocking foreign elements, part – in the production of the necessary antibodies.

Substances secreted by lymphocytes, cytokines, contribute to the activation of antigen-destroying cells, play an important role in the destruction of dangerous tumors formed in the body. In the case of a clear functioning of the immune system, they are also eliminated in the future.

But, if the body is prone to an inadequate reaction, an excessive amount of these biologically active substances is produced. And not all cytokines are destroyed after getting rid of antigens. Some of them oppose completely healthy cells of their own body, cause inflammation, and begin to destroy organs. This is the mechanism of development of an allergic reaction. It should be noted that the release of histamine and a number of other chemicals with increased activity by interacting cells is of particular importance.

Allergic reactions occur precisely in cases when the immune system is overly sensitive to the effects of antigens on the body.

Allergy is true and false

In addition to the true allergy, the so-called pseudoallergia (false allergy) is known.

A true allergy is manifested due to a violation of the immune system. The mechanism of occurrence of pseudoallergia is different. The latter differs from a true allergy in that antibodies do not participate in the process of its occurrence. In this case, the active substances (histamine, tyramine, serotonin, etc.) are released into the body as a result of the direct effect of antigens on cells.


The manifestations of true and false allergies have a great similarity. After all, in both cases, the reaction is caused by the same substances (in particular, histamine).

With an increase in the amount of histamine in the blood, there are signs characteristic of allergies, such as fever, urticaria, an increase or decrease in blood pressure, headache and dizziness, suffocation. These symptoms manifest themselves both with true allergies and with pseudoallergia.

The difficulty of diagnosis lies in the fact that many allergy tests show a negative result, because immunoglobulins do not come into conflict with antigens. It is possible to recognize the presence of an ailment only from the experience of repeated contacts with an allergen.

The release of biologically active substances can occur when eating certain foods, such as eggs, fish, as well as as a result of damage to cells during irradiation, contact with acids or alkalis, the action of certain medications, in extreme cold or heat.

A healthy body is able to neutralize a large amount of histamine on its own, reduce the activity of this substance to a safe level. But with diseases such as tuberculosis, dysbiosis or cirrhosis of the liver, the mechanism of counteraction is disrupted. The allergic person’s body also reacts inadequately to the presence of histamine. Therefore, food rich in proteins can cause a pseudoallergic reaction (after all, proteins contain amino acids, the derivatives of which are biologically active substances such as histamine and tyramine).

To distinguish a true allergy from a false one, some signs allow. In particular, a true allergy is accompanied by an increased content of class E immunoglobulins in the blood. An important indicator is also the relationship between the amount of allergen and the strength of the reaction caused by it.

This type of pseudoallergia, such as food intolerance, manifests itself much more often than a true allergy, which is associated with a violation of the mechanisms of the immune system.

So, with pseudoallergia (including food intolerance), the reaction increases in the case of an increase in the amount of food products intolerant by the body, flowering plants, household chemicals, etc.

And a true allergic reaction is caused even by a minimal dose of an allergen-containing substance (for example, a drug, plant pollen). In addition, the reaction associated with the failure of immunity often manifests itself in certain seasons (for example, when some plants bloom).

Of the truly allergic diseases, diseases caused by pollen of various plants were identified and investigated earlier than others. Their name – pollinoses – comes from the Latin word pollinus – “pollen”.

Back in the middle of the XVI century, the doctor Leonardo Botallus described pink fever – a disease caused by inhaling the fragrance of blooming roses and accompanied by fever, headache, inflammation of the mucous membranes of the nose and eyes, swelling of the skin, general malaise.

Further achievements in the study of the disease, called “hay fever”, belong to the English doctor Bostock (the beginning of the XVIII century).

Then new experiments and studies were conducted. Bostock’s compatriot, Blackley, managed to artificially cause various manifestations of allergies when plant pollen contacts damaged areas of the skin, mucous membranes of the eyes and nose. The tests developed by this researcher were later used in the diagnosis of allergic diseases and contributed to their successful treatment.

As the results of subsequent experiments have shown, pollinosis is caused by fine pollen that can penetrate into the bronchioles. In most cases, this category includes pollen of those plants that are pollinated by wind. In addition, it should be sufficiently volatile and remain viable for a long time. A humid environment, as a rule, enhances the effect of such an allergen. Usually, grass pollen is more active than the pollen of shrubs or trees.

The overwhelming number of pollinosis also occurs when exposed to pollen of the most common plants in this zone. In the regions of Central Europe, this category includes timofeevka, fescue, hedgehog, wormwood, quinoa, poplar, elm, linden. In the southern part of Russia, the main allergen is ragweed pollen. Therefore, the flowering periods of these plants are dangerous for allergy sufferers, especially in the morning (when a lot of pollen is emitted).

Allergies caused by ingestion of allergens through the respiratory tract are usually manifested by attacks of suffocation, cough, runny nose.

Sometimes pollinoses are combined with other forms of allergies that develop as a result of the action of infections, chemical and medicinal substances, and some foods.

The ability of products to cause allergies depends on their chemical composition and some other factors. Those of them that have a more complex protein composition are particularly allergenic. These include primarily milk and products made from it, chocolate, eggs, meat, fish, as well as some fruits, vegetables and berries.

Pseudoallergia, which is caused by certain foods, is called food intolerance. It may be associated with substances contained in the products: preservatives, dyes, etc.

For example, those people who are characterized by hypersensitivity to nitrates, it is recommended to limit the use of black radish, celery, beetroot, bacon, salted fish.

Intolerance to dairy products or allergy provoked by the latter is more common in people suffering from diseases of the digestive system – gastritis and gastroduodenitis, cholecystitis, dysbiosis. Lack of vitamins also leads to the development of negative reactions.

In the case of food allergies, disorders of the digestive system are usually observed, as well as urticaria and fever.

Dyes, turpentine, mineral oils and other chemicals, coming into contact with the skin, can cause allergies in the form of dermatitis. Infectious allergies can accompany diseases such as tuberculosis and typhoid fever.

Fermented milk products (kefir, cottage cheese and some others) are better absorbed by the body.

Sometimes allergens are produced in the body itself due to exposure to very high or very low temperatures or with some mechanical damage.

Allergy and immunology

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