Allergies are one of the global medico-social problems affecting mankind. Ailments caused by allergies take the third place after cardio-vascular and oncological disorders and even the first place in certain ecologically affected regions. Over the past 30 years the number of the victims of this disorder has been doubling every 10 years. Despite the progress and achievements of the fundamental areas of biology and medicine, intensive studies of the nature of allergies and development of new methods of treatment and disease prevention, even more acute forms are being observed causing temporary disabilities-reducing the quality of life of many patients. Allergy is often denounced as the "ailment of civilization". In the leading industrial countries the percentage of the affected people (mostly young ones) is much greater than in the developing ones. The reasons include-pollution of the environment with industrial wastes, unfavorable social conditions, increased consumption of medical drugs, intense use of disinfectants at home and at work, emphasis on herbicides and pesticides in farming and the advent of genetically modified foods. According to current statistics from 10 to 30 percent of the urban and rural population of Britain, Germany, France, etc. residing on territories with a highly developed economic potential are affected by allergic disorders. According to epidemiological studies conducted at the Institute of Immunology of the Ministry of Health and Social Development of the Russian Federation pathologies of this kind are present from 15 to 35 percent in different regions of Russia. An article published in the journal "Energia: Ekonomika, Tekhnika, Ecologia" (Energetics: Economics, Technology, Ecology) of the Russian Academy of Sciences, a researcher of this Institute Sergei Polner, Cand. Sc. (Med.) speaks of appreciable economic losses for the cure of not only allergies as such, but of the complications of viral and other infections associated with it. As a result, since the victims are people of young and most active age-groups, labor losses are increased and the level of popular health of a nation drops down.
The vary notion of "allergy", suggested in 1906 by the Austrian pediatrician Dr. Clemence Pirque, is described in present-day science as a pathologically increased response of the organism to substance of alien nature which are based on immunological mechanisms. Conditions characterized by the formation of antibodies and specifically reactive lymphocytes develop in response to a contact with an allergen (or allergens) which is regarded as the causal agent of an ailment.
Allergenes are divided into two groups. The first includes endo- or autoallergenes which are formed in the
organism itself. These are sensibilized (having increased sensitivity to contacts with some substance) lymphocytes, or modified under the effect of different factors (viruses, bacteria, etc.) components of cell tissues (tireoglobulin of the pancreas, myelin of muscle fibers, eye-crystal, etc. In normal conditions all of them are isolated from systems producing antibodies. But in pathological conditions this physiological isolation is broken which promotes the formation of endo-(auto-) allergens and the development of the associated reaction.
The second group includes exogenic substances of infectious and non-infectious origin which get in to organism from without. Their spectrum is great and differs according to the method of penetration: substances which are inhale (dust, particles of epidermis and animal fur, dyes, synthetic materials, poison chemicals, medicines); enteral, which are received through the digestive tract (fish, milk, nuts, eggs, etc., medicines, insect metabolites), parenteral which get in during administration of drugs and serums and insect bites. As for infectious exoallergenes, they include bacterial (non-pathogenic and pathogenic bacteria and products of their vital activities); viral ones (different types of rhinoviruses and products of their interaction with body tissues); parasitic (antigens of helmints, lambia, etc.)
The organism responds to the penetration of an allergen by increased sensitivity-sensibilization. What this situation is repeated there are formed specific proteins-antibodies with special biological properties.
All allergens possess a broad spectrum of activities. For example, one and the same agent can provoke dermatitis and a fit of bronchial asthma. Another one, causing allergic rhinitis, can provoke food allergies, etc. In most cases patient develops sensitivity to several agents belonging to different groups at the same time. Most often this is connected with "crossectional" properties of allergens caused by the presence of epitops in their molecules. Therefore there are many people suffering from what we call a polyvalent form of disorders (increased sensitivity to several allergens at one and the same time).
But what we call inadequate reactions are caused not only by the aforesaid substances-"full value" allergens-but substances free from them, although alien to the human organism. These are known as haptenes. These include many micromolecular compounds (some medicinal preparations), simple chemicals (bromine, iodine, nickel, etc.), more complicated protein-polysac-charide complexes of plant polline and other factors of the environment of natural or anthropogenic origin. Getting into the organism they do not trigger immune mechanisms, and they become allergens when associated with tissue proteins. Produced as a result are conjugated or complex antigens which play a sensibilizing role.
When they get into the organism repeatedly, haptenes often combine with the newly formed antibodies and/or sensibilized lymphocytes independently, without preliminary links with proteins, thus provoking the development of an allergic reaction. But the role of haptenes is performed not by all substances, but by a certain part of it-chemical grouping. Identical groupings can be included into different substances. Therefore sensibilization to one of them can precipitate allergic reactions to other and similar ones.
Polner pointed out that the multitude of allergens around us, only a certain percentage of people are prone to a certain pathology. That depends on the degree of allergenicity of the factors involved and also by changing reactivity of the organism which is often directly associated with genetic predisposition.
One of the most common ailments now associated with upsets of the immune response is bronchial asthma: chronic inflammation of respiratory organs which increases their sensitivity to various irritants, including those present in the air. The main manifestation thereof are fit-like upsets of bronchial conductivity-episodes of asphyxia, coughing and fits of rale. The numbers of such cases are really impressive - the minimum of 300 mn people (5 to 15 percent of world population). The number of such cases has doubled over the past 15 years. About one in every 12 Russians is suffering from bronchial asthma and there have been no tendencies for declines in its propagation.
In the opinion of Polner, the prevention and cure of this disease remains one of the most acute problems in world medicine because of the inadequate qualification of general practitioners. Despite a very clear clinical picture of the disease and current diagnostics techniques, asthma is often mistaken for bronchitis. In three out of five patients the correct diagnosis is established at late stages only.
Also very common is allergic rhinitis. Specialists believe that it very closely affects the beginning, gravity and progression of bronchial asthma. Since the upper and lower respiratory channels are one single whole, in cases of both pathologies one observes an increased sensitivity of the mucosa of the nose and the bronchi to non-specific irritants and influences. This question so far remains unanswered and finding an answer to it could be promoted by diagnostic techniques suggested by our domestic researchers.
S. Polner, "Sickness of Civilization " (Energia: Ekonomika, Tekhnika, Ecologia journal), No. 9, 2005
Prepared by Sergei POPOV
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