Childhood diseases - how a child’s immunity is formed. How is children's immunity formed? Development of protective mechanisms of the child’s immune system The child’s immunity begins to develop at 3 months

Anatomical and physiological features, reserve capabilities.

Development immune system the body continues throughout childhood. During the growth of a child and the development of his immune system, “critical” periods are distinguished, which are periods of maximum risk of developing inadequate or paradoxical reactions of the immune system when the child’s immune system encounters an antigen.

The first critical period is the neonatal period (up to 29 days of life). During this period of postnatal adaptation, the formation of the immune system is just beginning. The child's body is protected almost exclusively by maternal antibodies obtained through the placenta and breast milk. Sensitivity of a newborn baby to bacterial and viral infections very high during this period.

The second critical period (4 - 6 months of life) is characterized by the loss of passive immunity received from the mother due to the catabolism of maternal antibodies in the child's body. The child’s ability to form his own active immunity develops gradually and during this period is limited to the predominant synthesis of immunoglobulin M - antibodies without the formation of immunological memory. The insufficiency of local protection of the mucous membranes is associated with the later accumulation of secretory immunoglobulin A. In this regard, the child’s sensitivity to many airborne and intestinal infections during this period is very high.

The third critical period (2nd year of life), when the child’s contacts with outside world and with infectious agents. The child’s immune response to infectious antigens remains defective: the synthesis of immunoglobulins M predominates, and the synthesis of immunoglobulins G suffers from insufficient production of one of the most important subclass G2 for antibacterial protection. Local mucosal protection is still imperfect due to the low level of secretory IgA. The child's sensitivity to respiratory and intestinal infections is still high.

The fifth critical period is adolescence (for girls from 12 to 13 years old, for boys from 14 to 15 years old), when the pubertal growth spurt is combined with a decrease in the mass of lymphoid organs, and the beginning of the secretion of sex hormones (including androgens) causes depression cellular mechanisms of immunity. At this age, external, often unfavorable, effects on the immune system increase sharply. Children of this age are characterized by high sensitivity to viral infections.

In each of these periods, the child is characterized by anatomical, physiological and regulatory features of the immune system.

At birth, neutrophils predominate in the child’s blood, often with a shift in the leukocyte formula to the left to myelocytes. By the end of the first week of life, the number of neutrophils and lymphocytes levels off - the so-called “first crossover” - with a subsequent increase in the number of lymphocytes, which in the next 4 - 5 years of life remain the predominant cells among the child’s blood leukocytes. The “second crossover” occurs in a child aged 6–7 years, when the absolute and relative number of lymphocytes decreases and leukocyte formula takes on the appearance characteristic of adults.

Granulocytes of newborns are characterized by reduced functional activity and insufficient bactericidal activity. The functional deficiency of neutrophils in newborn children is to some extent compensated by a large number of these cells in the blood. In addition, granulocytes of newborns and children of the first year of life differ from granulocytes of adults in a higher level of receptors for IgG, necessary for the cleansing of bacteria from the body mediated by specific antibodies.

The absolute number of blood monocytes in newborns is higher than in older children, but they are characterized by low bactericidal activity and insufficient migration ability. The protective role of phagocytosis in newborns is limited by the underdevelopment of the complement system, which is necessary to enhance phagocytosis. Monocytes of newborns differ from monocytes of adults in their higher sensitivity to the activating effect of interferon gamma, which compensates for their initial low functional activity, because Interferon gamma activates all protective functions of monocytes. promoting their differentiation into macrophages.

The content of lysozyme in the serum of a newborn exceeds the level of maternal blood already at birth; this level increases during the first days of life, and by the 7th - 8th day of life it decreases slightly and reaches the level of adults. Lysozyme is one of the factors that ensures the bactericidal properties of the blood of newborns. In the tear fluid of newborns, the content of lysozyme is lower than in adults, which is associated with an increased incidence of conjunctivitis in newborns.

In umbilical cord blood at the birth of a child, the total level of hemolytic activity of complement, the content of complement components C3 and C4, and factor B are about 50% of the level of maternal blood. Along with this, the level of membrane attack complex components C8 and C9 in the blood of newborns barely reaches 10% of the level of adults. The low content of factor B and component C3 in the blood of newborns is the cause of insufficient auxiliary activity of the blood serum when interacting with phagocytic cells. The above-described defects in the phagocytic activity of granulocytes and monocytes in the newborn are associated with this. By approximately the 3rd month of postnatal life, the content of the main components of complement reaches levels characteristic of an adult organism. In conditions of inability to develop effective specific immunity in children early age The main burden in the processes of cleansing the body of pathogens falls on the alternative pathway of activation of the complement system. However, in newborns, the alternative complement activation system is weakened due to deficiency of factor B and properdin. Only by the second year of life does the production of components of the complement system finally mature.

The content of natural killer cells in the blood of newborns is significantly lower than in adults. Natural killer cells in children's blood are characterized by reduced cytotoxicity. A decrease in the secretory activity of natural killer cells in a newborn is indirectly evidenced by the weakened synthesis of interferon gamma.

As can be seen from the above, in newborn children all the basic mechanisms of nonspecific defense of the body against pathogenic bacteria and viruses are sharply weakened, which explains the high sensitivity of newborns and children of the first year of life to bacterial and viral infections.

After birth, the child’s immune system receives a strong stimulus for rapid development in the form of a flow of foreign (microbial) antigens entering the child’s body through the skin, mucous membranes of the respiratory tract, and gastrointestinal tract, which are actively populated by microflora in the first hours after birth. The rapid development of the immune system is manifested by an increase in the mass of lymph nodes, which are populated by T and B lymphocytes. After the birth of a child, the absolute number of lymphocytes in the blood increases sharply already in the 1st week of life (the first crossover in the white blood formula). Physiological age-related lymphocytosis persists for 5 to 6 years of life and can be considered compensatory.

The relative number of T lymphocytes in newborns is reduced compared to adults, but due to age-related lymphocytosis, the absolute number of T lymphocytes in the blood of newborns is even higher than in adults. The functional activity of T-lymphocytes in newborns has its own characteristics: high proliferative activity of cells is combined with a reduced ability of T-lymphocytes to respond by proliferation to contact with antigens. A feature of T-lymphocytes in newborns is the presence in their blood of about 25% of cells bearing signs of the early stages of intrathymic differentiation of T-cells. This indicates the release of immature thymocytes into the bloodstream. Lymphocytes of a newborn have increased sensitivity to the action of interleukin-4, which predetermines the predominance of Th2 differentiation in them.

In a newborn, the thymus is fully formed during the first year of life and reaches its maximum size (Fig. 3-6). The intense functioning of the thymus, in which all T-lymphocytes undergo maturation, persists during the first 2 to 3 years of life. During these years, there is a constant proliferation of thymocytes in the thymus - the precursors of T-lymphocytes: of the total number of 210 8 thymocytes, 20-25% (i.e. 510 7 cells) are newly formed daily during their division. But only 2-5% (i.e. 110 6) of them enter the blood daily in the form of mature T-lymphocytes and settle in lymphoid organs. This means that 50 10 6 (i.e. 95-98%) thymocytes die every day in the thymus, and only 2-5% of cells survive. From the thymus, only T-lymphocytes that carry receptors capable of recognizing foreign antigens in combination with their own histocompatibility antigens enter the bloodstream and lymphoid organs. Such mature T lymphocytes respond to antigen recognition by proliferation, differentiation, and activation of protective functions during a specific immune response. The rapid increase in thymus mass in the first 3 months of life continues at a slower pace until 6 years of age, after which the thymus mass begins to decline. From the age of two, the production of T-lymphocytes also begins to decline. The process of age-related involution of the thymus accelerates during puberty. During the first half of life, true thymic tissue is gradually replaced by adipose and connective tissue (Fig. 3-6). It follows from this that the thymus manages to carry out its main function of forming a pool of T-lymphocytes in the first years of life.

In the first years of life, against the background of maximum intensity of the maturation processes of T-lymphocytes in the thymus, primary contacts of the body with antigens of pathogenic microorganisms occur, which leads to the formation of clones of long-lived T-cells of immunological memory. During the first three years of life, children are routinely vaccinated against all the most dangerous and common infectious diseases: tuberculosis, polomyelitis, diphtheria, tetanus, whooping cough, measles. At this age, the body’s immune system responds to vaccination (killed or weakened pathogens, their antigens, their neutralized toxins) by producing active immunity, i.e. formation of clones of long-lived memory T cells.

A significant defect in T-lymphocytes in newborns is reduced quantity they have receptors for cytokines: interleukins 2, 4, 6, 7, tumor necrotizing factor-alpha, interferon gamma. A feature of T-lymphocytes in newborns is the weak synthesis of interleukin-2, cytotoxic factors and interferon gamma. In newborns, the activity of mobilizing T-lymphocytes from the bloodstream is reduced. This explains the weakened or negative results of T-dependent skin allergy tests (for example, tuberculin test) in young children. In contrast, a rapid increase in the levels of proinflammatory cytokines (tumor necrotizing factor alpha, interleukin-1) in the blood of newborns during the development of sepsis indicates early maturation of the mechanisms of production and secretion of proinflammatory cytokines.

Absolute and relative lymphocytosis in the blood of children up to the prepubertal period reflects the process of accumulation of clones of lymphocytes that have specific receptors for recognizing various foreign antigens. This process is completed mainly by 5-7 years, which is manifested by a change in the blood formula: lymphocytes cease to dominate and neutrophils begin to predominate (Fig. 3-7).

The lymphoid organs of a young child respond to any infection or any inflammatory process with severe and persistent hyperplasia (lymphadenopathy). At birth, a child has mucosal associated lymphoid tissues (MALT), potentially capable of responding to antigenic stimuli. Children in the first years of life are characterized by a response to infections with hyperplasia of MALT, for example MALT of the larynx, which is associated with an increased frequency and danger of rapid development of edema in the larynx in children during infections and allergic reactions. MALT gastrointestinal tract, in children of the first years of life remains immature, which is associated with a high risk of intestinal infections. The low efficiency of the immune response to infectious antigens entering through the mucous membranes in children of the first years of life is also associated with delayed maturation of the population of dendritic cells - the main antigen-presenting cells of MALT. Postnatal development of MALT in children depends on the feeding system, vaccination, and infection.

In terms of the number of B-lymphocytes in the blood of newborns and their ability to produce a proliferative response to antigens, no significant differences from B-lymphocytes of adults were detected. However, their functional inferiority is manifested in the fact that they give rise to antibody producers that synthesize only immunoglobulin M and do not differentiate into memory cells. This is related to the peculiarities of the synthesis of antibodies in the body of newborns - only class M immunoglobulins accumulate in their bloodstream, and immunoglobulin G in the blood of a newborn is of maternal origin. The content of immunoglobulin G in the blood of a newborn does not differ from the level of this immunoglobulin in the blood of the mother (about 12 g/l); all subclasses of immunoglobulin G pass through the placenta. During the first 2 - 3 weeks of a child's life, the level of maternal immunoglobulin G decreases sharply as a result of their catabolism. Against the background of a very weak child’s own synthesis of immunoglobulin G, this leads to a decrease in the concentration of immunoglobulin G between the 2nd and 6th months of life. During this period, the antibacterial protection of the child’s body is sharply reduced, because IgG are the main protective antibodies. The ability to synthesize one’s own immunoglobulins G begins to appear after 2 months of age, but only by the prepubertal period does the level of immunoglobulins G reach the level of adults (Fig. 3-8).

Neither immunoglobulin M nor immunoglobulin A have the ability to transfer transplacentally from the mother's body to the child's body. Immunoglobulin M synthesized in the child's body is present in the newborn's serum in a very small amount (0.01 g/l). An increased level of this immunoglobulin (over 0.02 g/l) indicates an intrauterine infection or intrauterine antigenic stimulation of the fetal immune system. The level of immunoglobulin M in a child reaches adult levels by the age of 6 years. In the first year of life, the child’s immune system responds to various antigenic influences by producing only immunoglobulin M. The immune system acquires the ability to switch the synthesis of immunoglobulins from Ig M to Ig G as it matures, as a result of which, in the prepubertal period, a balance of different classes of immunoglobulins is established in the blood, characteristic for adults and provides antibacterial protection to both the bloodstream and body tissues.

Immunoglobulin A in the blood of newborns is either absent or present in small quantities (0.01 g/l), and only at a much older age reaches the level of adults (after 10 - 12 years). Class A secretory immunoglobulins and the secretory component are absent in newborns, but appear in secretions after the 3rd month of life. Typical adult levels of secretory immunoglobulin A in mucosal secretions are reached by the age of 2–4 years. Until this age, local protection of the mucous membranes, depending mainly on the level of secretory IgA, remains sharply weakened in children. During breastfeeding, the insufficiency of local mucosal immunity is partially compensated by the intake of secretory immunoglobulin A with mother's milk.

Despite the early start of the formation of elements of the immune system in ontogenesis (on the 40th day of pregnancy), by the time the child is born, his immune system remains immature and unable to provide full protection of the body from infections. In a newborn, the mucous membranes of the respiratory and gastrointestinal tracts are poorly protected - the entrance gates for most infections. Lack of mucosal protection associated with the late onset of immunoglobulin A synthesis and secretory IgA production throughout childhood remains one of the reasons for the increased sensitivity of children to respiratory and intestinal infections. The weakened anti-infective defense of the child’s body is aggravated during periods of decreased levels of protective IgG in the bloodstream (between the second and sixth months of life). At the same time, in the first years of a child’s life, primary contact with the majority of foreign antigens occurs, which leads to the maturation of organs and cells of the immune system, to the accumulation of the potential of T- and B-lymphocytes, which can subsequently respond with a protective immune response to pathogens entering the body. microorganisms. All four critical periods of childhood - the neonatal period, the period of loss of maternal protective antibodies (3 - 6 months), the period of a sharp expansion of the child’s contacts with the outside world (2nd year of life) and the period of the second crossover in the content of blood cells (4 - 6 years ) are periods of high risk of developing infections in the child’s body. Inadequacy of both cellular and humoral immunity makes it possible to develop chronic recurrent infections, food allergies, various atopic reactions and even autoimmune diseases. Individual characteristics of the development and maturation of the immune system during childhood determine the immune status of an adult. It is in childhood, during the heyday of the thymus functions, that specific antimicrobial immunity and the corresponding immunological memory are formed, which should be sufficient for the rest of life.

Reserve capabilities for protecting the newborn's body are associated with breastfeeding. With mother's milk, ready-made antibacterial and antiviral antibodies - secretory IgA and IgG - enter the child's body. Secretory antibodies act directly on the mucous membranes of the gastrointestinal and respiratory tracts and protect these mucous membranes of the child from infections. Due to the presence of special receptors on the mucous membrane of the gastrointestinal tract of the newborn, immunoglobulins G penetrate from the child’s gastrointestinal tract into his bloodstream, where they replenish the supply of maternal IgG previously received through the placenta. The reserve capabilities of protecting the child’s body are associated with an increased number of leukocytes circulating in the body, which partially compensates for their functional inferiority.

Risk factors.

The above-described signs of immaturity of the immune system of a child in the first years of life indicate imperfection of anti-infective protection. That's why infections represent the most important risk factor for the immune system of children. The group at increased risk of developing infections among newborns are premature infants, and among them are low birth weight infants who suffer from the most pronounced and persistent immunological defects. In children of the first years of life, an inability to develop a full immune response to polysaccharide antigens, which are widespread in pathogenic bacteria (Streptococcus pneumonie, Klebsiella pneumonie), was revealed. The insufficiency of local mucosal immunity in children leads to the possibility of penetration of microorganisms - pathogens of respiratory and intestinal infections - through these entrance gates. The weakness of cellular defense mechanisms makes children especially sensitive to viral and fungal infections, protection against which requires the participation of functionally complete T-lymphocytes. It is precisely due to the defectiveness of cellular defense mechanisms that a high risk of tuberculosis remains throughout childhood due to the widespread circulation of the tuberculosis pathogen. Sensitivity to many infections increases sharply in children after 6 months of life, from the moment of loss of passive immunity - antibodies received from the mother. The risk of developing infections in childhood against the background of an underdeveloped immune system is associated not only with a danger to the child’s life, but also with the danger of long-term consequences. Thus, many neurological diseases of adults are etiologically associated with infections suffered in childhood: measles, chicken pox and others, the pathogens of which are not removed from the body due to the low efficiency of cellular immunity in children, remain in the body for a long time, becoming triggers for the development of autoimmune diseases in adults, such as multiple sclerosis, systemic lupus erythematosus.

Table 3-3.

Risk factors affecting the immune system of children

RISK FACTORS	PREVENTION MEASURES
Infections	Specific vaccination. Breast-feeding
Malnutrition	Breast-feeding. Design of infant formula. Balanced children's diets.
Acquisition hypersensitivity to antigens environment, allergization	Prevention of prenatal contacts with allergens. Rational baby food.Complexes of vitamins and microelements. Breast-feeding
Environmental troubles	Rational baby food. Complexes of vitamins and microelements.
Psycho-emotional stress	Explanatory work with parents, educators, teachers. Complexes of vitamins and microelements.
Excessive insolation (UV exposure)	Strict adherence to the daily routine, limiting the time of sun exposure for children

The gradual colonization of the child’s mucous membranes with microorganisms contributes to the maturation of his immune system. Thus, the microflora of the airways comes into contact with the MALT of the respiratory tract, microbial antigens are captured by local dendritic cells and macrophages, which migrate to regional lymph nodes and secrete proinflammatory cytokines, which increases the production of interferon gamma and Th1 differentiation. Microorganisms penetrating through the gastrointestinal tract are the main drivers of postnatal maturation of the child’s entire immune system. As a result, an optimal balance of Th1 and Th2, responsible for the cellular and humoral immune response, is established in the maturing immune system.

As the child’s immune system matures and the mechanisms of a specific immune response improve, the risk of an overreaction of his immune system to contact with environmental and developmental antigens increases. allergic reactions. Even prenatal contact of the fetus with pollen allergens inhaled by the mother leads to the subsequent development of atopic reactions and diseases in the newborn. High risk the development of atopic reactions in children of the first years of life is associated with the predominance of Th2 differentiation in them, which controls the synthesis of immunoglobulin E and increased secretion of histamine by basophils and mast cells. The low level of secretory IgA on the mucous membranes of children facilitates the unhindered penetration of allergens through the mucous membranes of the respiratory and gastrointestinal tract. A feature of atopic reactions in children of the first years of life can be considered a higher frequency of food and lower frequency of dust/pollen allergies compared to adults. Children are often allergic to cow's milk (2 - 3% of children in industrialized countries). Cow's milk contains more than 20 protein components, and many of them can cause the synthesis of immunoglobulin E. The widespread occurrence of such allergies makes it difficult to artificially feed children, forcing them to look for adequate substitutes (for example, soy products).

Past infections have a persistent nonspecific effect on the nature of the child’s immune response to other antigens. For example, among children who have had measles, the incidence of atopy and allergy to house dust is halved compared to children who have not had measles. The measles virus causes a systemic switch to Th1 differentiation. Mycobacteria, including the BCG vaccine, are also Th1 activators. After children are vaccinated with the BCG vaccine, the tuberculin skin test (an indicator of an active cellular immune response) becomes positive and children who had symptoms of atopy before revaccination lose them. In contrast, vaccination with diphtheria-tetanus-pertussis vaccine (DTP), which induces a Th2-mediated response, not only does not have a protective effect against atopy, but may increase the incidence of Th2-mediated atopic diseases in children.

A risk factor affecting the child's immune system is malnutrition of the mother during pregnancy or the child itself.. There is a relationship between malnutrition and infections in children: on the one hand, the low social status of parents, poor nutrition children contribute to a weakening of the immune system and increased sensitivity to infections, on the other hand, infections lead to loss of appetite, the development of anorexia, malabsorption, i.e. to deterioration of nutrition. In this regard, malnutrition and infections are considered as two interrelated major factors that determine the environmental background of morbidity in children, especially in developing countries. A direct correlation has been shown between the infectious morbidity of children in developing countries and the degree to which their body weight lags behind the age norm, with which the low efficiency of cellular immunity also correlates.

A risk factor for the immune system of children is stress. Long separation from the mother is stressful for a child in the first year of life. In children who were early deprived of maternal attention, defects in cellular immunity were identified, which persist throughout the first two years of the child’s life. For preschool children, the most important are the socio-economic conditions of the family’s life, which can cause them psychosocial stress. Stress, as a rule, is accompanied by temporary suppression of immune mechanisms, against the background of which the child’s sensitivity to infections sharply increases. In children living in the Far North, inhibition of nonspecific defense factors (phagocytic cells, natural killer cells), a change in the ratio of certain classes of immunoglobulins in the blood serum was revealed: an increase in the level of immunoglobulin M, a decrease in the content of immunoglobulins G, a decrease in the content of secretory immunoglobulin A in saliva and a decrease in tension specific anti-infective immunity formed in response to vaccination.

A stressful factor for children is the effect of light through the visual system on certain areas of the brain or through the skin. Visible light(400-700 nm) can penetrate the layers of the epidermis and dermis and act directly on circulating lymphocytes, changing their functions. Unlike the visible part of the spectrum, irradiation ultraviolet rays UV-B (280-320 nm), UV-A (320-400 nm), acting through the skin, can inhibit immunological functions. The most pronounced inhibition by ultraviolet irradiation of the mechanisms of cellular immunity, the production of certain cytokines and growth factors. These data force us to consider insolation as one of the risk factors affecting the immune system of children.

One of the reliable methods of activating the immune system and preventing infections in children is vaccination. To ensure passive immunity of a newborn in the first months of life, vaccination of pregnant women is quite effective: against tetanus, diphtheria, hepatitis B, staphylococcus, streptococcus. Newborn children are vaccinated against tuberculosis, whooping cough, diphtheria, tetanus, measles, and polio during the first year of life, followed by revaccination throughout childhood and adolescence.

Increasing the reserves of the immune system and preventing infections in newborns is achieved breastfeeding. Human milk contains not only a complex necessary for the child food components, but also the most important factors of nonspecific protection and products of a specific immune response in the form of secretory immunoglobulins of class A. Secretory IgA supplied with breast milk improves the local protection of the mucous membranes of the gastrointestinal, respiratory and even genitourinary tract of the child. Breastfeeding, through the introduction of ready-made antibacterial and antiviral antibodies of the SIgA class, significantly increases the resistance of children against intestinal infections, respiratory infections, and otitis media caused by Haemophilus influenzae. The mother's immunoglobulins and lymphocytes supplied with breast milk stimulate the baby's immune system, providing long-term antibacterial and antiviral immunity. Breastfeeding increases the immune response of children to administered vaccines. Breastfeeding hinders development allergic diseases and the autoimmune disease celiac disease. One of the components breast milk- lactoferrin is involved in the stimulation of immunological functions, being able to penetrate immunocompetent cells, bind to DNA, inducing transcription of cytokine genes. Components of breast milk such as specific antibodies, bacteriocidins, and bacterial adhesion inhibitors have direct antibacterial activity. All of the above requires a lot of attention in preventive work with pregnant women to explain the benefits of breastfeeding. Special educational programs that involve not only women, but also their husbands, parents and other persons who can influence a woman’s decision to breastfeed her child are useful (Fig. 3-9).

The task of designing infant formulas that can replace breast-feeding not only by nutritional value, but also by its stimulating effect on the child’s immune system. It is planned to introduce into such mixtures the necessary cytokines and growth factors obtained using genetic engineering technologies.

Rational baby nutrition is one of the universal ways to maintain the proper development and maturation of the immune system and prevent infections and other diseases in children, for example, the consequences of stressors on the child’s immune system. Lactic acid products containing live lactic acid bacteria serve as a safe source of antigens that act at the MALT level of the gastrointestinal tract, promoting the maturation of antigen-presenting cells and T lymphocytes. Use of nucleotides as food additives accelerates the maturation of the immune system in premature newborns. The following are recommended as food supplements for weakened children: glutamine, arginine and omega-3 fatty acid, helping to establish a balance between the cellular and humoral mechanisms of the immune response. The introduction of zinc as a dietary supplement is used to normalize body weight and immunological functions in children. In the serum of premature newborns, the concentration of vitamin A (retinol) is significantly lower than in full-term newborns, which is the basis for the use of vitamin A as a nutritional supplement for the former. Complexes of vitamins and microelements are recommended for permanent use children of the first years of life, which contributes to the maturation of their immune system (Table 3-3).

Children with severe manifestations of immunodeficiency are treated with replacement therapy. For example, they try to compensate for the lack of immunoglobulin G by introducing donor immunoglobulin. However, the injected donor IgG has an even shorter half-life of circulation in the child's body than maternal IgG. Prevention of infections in neutropenia in children is associated with the use of growth factor drugs: G-CSF and GM-CSF, which stimulate myelopoiesis and increase the number and activity of phagocytic cells in the child’s blood.

Children who attend child care institutions get sick more often infectious diseases than those who, up to a certain age, are in conditions home care. However, children who get sick more often are likely to be less likely to get sick in the future.

It is believed that children who get sick more often preschool age(and these, in most cases, are precisely those children who go to kindergartens) are exposed to the influence of many different viruses, “training” their immune system. Therefore, they get sick less in the future.

Immunity is the body's ability to resist various factors that can cause diseases, that is, viruses, bacteria, some fungi. There are two types of immunity - nonspecific, that is, the kind that a child has from birth, and specific - acquired immunity, which is produced after contracting a certain disease or after vaccination. Main feature this type of immunity is the memorization of various pathogens (factors, causing diseases) that the child’s body encounters with the possibility of their subsequent recognition and fight against them.

Immediately after birth, the baby's immune system is immature. Of course, the baby has some innate protection, largely due to the antibodies it received in the womb. Breastfed children also receive immune protection factors from their mother's milk. But the baby's immune system begins to strengthen significantly when the child is exposed to bacteria and viruses from the environment. Various pathogens activate the production of natural antibodies, and the child is better able to fight infections in the future. This means that children who are exposed to the most infectious diseases from an early age are likely to have stronger immune systems when they start school.

The idea that children who get sick more often in preschool age benefit from this to increase immunity in the future is just a theory. There is enough research to support this. In particular, an observation of the health status of 4,750 children conducted in 2013 by the US Department of Pediatrics showed that those who attended children's groups and were sick more during the first five years of life subsequently experienced a decrease in the incidence rate (according to the same diseases) by 60 percent.

It is not known exactly how long antibodies remain in the human body, as they are so numerous and the immune processes are quite complex, but one recent discovery gives us an idea of ​​the potential of human defenses. Monitoring of people born in 1955 and surviving the 1957-1958 influenza pandemic showed that even after 50 years the concentration of antibodies to this virus in the blood is quite high (we are talking about the so-called “Asian” flu pandemic, which killed about 70 000 lives).

Some parents mistakenly believe that a sign of significantly weakened immunity is, for example, colds, which periodically occur in a child. But we should not forget that this is what helps to potentially form strong defense baby. During illness children's body learns to respond adequately in response to various pathogens. If a child suffers from colds only three or four times a year, then there is no need to artificially strengthen the immune system.

The human body is configured to fight infections. In any case, sooner or later, our children will be exposed to pathogens from the environment. It's just a matter of time. It has been proven that healthy life in adulthood depends on how the child’s immune system was strengthened during the first 3 years, while the foundation of immunity is laid in the 1st year of life.

So don't be afraid of seasonal diseases! Of course, I'm very sorry for the baby. However, illness is something of a charge for the immune system. He learns to fight back against viruses and bacteria and produces protection. The next time you meet a familiar enemy, the body will instantly react, remembering the method of struggle. This means that the disease will pass unnoticed or in a mild form.

It should be noted how important correct actions with the child during and especially after the disease to consolidate the positive effect in the baby’s body. When a child has a slight runny nose for several days, without coughing, fever and significant deterioration general condition and she is taken to kindergarten immediately after her illness ends - this is acceptable. But those parents are wrong when they force events after a more serious illness in the child - influenza, bronchitis, otitis media and others.

The deeper the disease affects the child’s body, the longer the recovery period should be. This also applies to strengthening the body’s potential for further resistance to such a disease. All parents remember physical measures to help protect themselves from illness. We emphasize that emotional peace and a friendly attitude towards the baby during the recovery period are also necessary.

Immunity - most important property human body. Immune defense is complex and multi-stage, it begins to function in the prenatal period, improves and develops continuously throughout life, protects the body from the penetration of substances foreign to it.

There are two main types of immunity: hereditary (species) and acquired (individual). Species immunity makes a person immune to many animal diseases (for example, canine distemper) and is inherited by subsequent generations. Individual immunity is developed throughout the life of each person and is not inherited.

There is also a distinction between active and passive immunity. Active immunity is produced by the body itself after an infectious disease or the administration of a vaccine (vaccination) that contains weakened or killed infectious agents. Passive immunity appears after the introduction of ready-made antibodies into the body, which are contained in serum (as well as the transfer of antibodies from mother to child during pregnancy through the placenta). Active immunity develops over time and lasts a long time; passive immunity appears immediately, but soon disappears. Accordingly, active immunity (vaccines) is used for prevention, and passive immunity (serums) is used for the treatment of infectious diseases.

Immune response

Any substance whose structure differs from the structure of human tissue is capable of causing an immune response. It is not specific and specific. A non-specific immune response is the first stage in the fight against infection. This mechanism starts immediately after the microbe enters the body, is almost the same for all types of microbes and implies the primary destruction of the microbe and the formation of a focus of inflammation. Inflammatory reaction This is a universal protective process that is aimed at preventing the spread of the microbe. Not specific immunity determines the overall resistance of the body.

A specific immune response is the second phase of the protective reaction: the body recognizes the microbe and develops a special defense against it. The specific immune response, in turn, is also of two types: cellular and humoral. The body can neutralize a foreign substance (antigen) by producing active cells, capturing and digesting antigen. This cellular immunity. The main elements of the body's immune system are special white blood cells - lymphocytes. If the antigen is destroyed with the help of special chemically active molecules - antibodies, then we are talking about humoral immunity(from lat. " humor" - liquid). The role of antibodies is performed by proteins (immunoglobulins) in the blood.

Features of newborn immunity

A child's immunity begins to develop in the womb. During this period, the main role is played by heredity, that is, the characteristics of the immune system of the parents. Besides great importance has a successful pregnancy, lifestyle expectant mother(the nature of her diet, compliance with the doctor’s recommendations).

The synthesis of the fetus's own antibodies begins around 10-12 weeks of pregnancy. However, the fetus is able to produce only a limited amount of immunoglobulins. The basis of immunity in newborns is the mother's antibodies. The process of transfer of antibodies from mother to fetus occurs mainly at the end of pregnancy, so premature babies are not sufficiently protected from infections compared to babies born at term.

The state of the child's immune system depends on many factors, including how the baby is fed. The role of breast milk, the protective properties of which are well known, is especially great. It has been proven that breastfed children are less likely to suffer from infectious diseases, since breast milk contains many maternal antibodies and special cells that can absorb microbes. True, antibodies obtained in this way act only in the intestines. They protect the child well from intestinal infections. In addition, the proteins of mother's milk are devoid of allergenic properties, so breastfeeding is the prevention of allergic diseases.

Interestingly, the newborn’s immune system is in a state of physiological suppression. This is a natural protective reaction of the body, the meaning of which is to prevent the development of violent immune reactions that could develop when a newly born baby comes into contact with a huge amount microorganisms in the environment. The first 28 days of life are considered the first critical period in the development of the immune system. At this time, the baby is especially susceptible to viral infections and the effects of microbes. In addition, another feature of the immunity of children in the first months of life is the inability to limit infection: any infectious process can quickly spread to the child’s entire body (this is called generalization of infection). That is why it is necessary, for example, to take very careful care of the healing umbilical wound.

The second critical period is 3-6 months of life. Maternal antibodies are gradually destroyed in the child’s body. But in response to the penetration of infection, a primary immune response develops in the baby’s body. It is characterized by the fact that it leaves no immunological memory. The next time the child encounters the same microorganism, the child will get sick just like the first time. During this period, children are exposed to various types of viruses that cause ARVI, and there is a high incidence of intestinal infections, inflammatory diseases of the respiratory system. Also, childhood infections are severe and atypical if the child has not received maternal antibodies (the mother herself was not sick, was not vaccinated, and did not breastfeed). At the same time, food allergies may appear.

The third critical period is 2-3 years of a child’s life. There is an expansion of contacts with the outside world. At the same time, the primary immune response remains the main one in the functioning of the immune system. The local immune system remains undeveloped; children are especially prone to repeated viral infections and inflammatory diseases respiratory organs.

The fourth critical period is 6-7 years. The levels of immunoglobulins correspond to the parameters in adults, however, the local immunity of the mucous membranes remains imperfect. At the age of 6-7 years, many chronic diseases develop, and the frequency of allergic diseases increases.

Fifth critical period - adolescence(12-13 years old for girls and 14-15 years old for boys). A period of rapid growth and hormonal changes is combined with a decrease in lymphoid organs, which play a large role in the system immune defense. After a period of decline, a new increase in frequency is observed chronic diseases. The severity of atopic diseases (bronchial asthma, etc.) weakens in many children.

Knowledge of the mechanisms of immune development and critical periods in the development of a child’s immune system is extremely important not only for doctors, but also for mothers. This is important for maintaining the health of our children and preventing their development various diseases. And, as you know, prevention is always better than cure.

Protects the first 28 days of a newborn's life children's immunity, acquired from the mother during the period of intrauterine formation. At this time, he is most susceptible to various infectious diseases. But on day 5, changes occur in the blood formula, and lymphocytes begin to predominate. Continuing breastfeeding during this period helps maintain immune protection.

Certain factors affecting the baby reduce immunity, which will contribute to frequent illnesses. Important role plays acquired immunity, which is inherited. There are also specific, active, passive, innate, specific and nonspecific immunity.

The acquisition of specific immunity in a child or natural occurs during life, through contact with pathogens (microbes, bacteria, viruses, fungi). It can be passive and active. The latter develops in response to the introduction of serums. Active immunity occurs after exposure to the disease.

Signs weak immunity will be:

• • frequent colds, more than 5 times a year;
  • low sensitivity to the treatment used;
  • tearfulness and irritability;

• pale skin;
• disorders of the digestive system;
• long recovery after illness;
• Colds end in complications - otitis, bronchitis, laryngitis, sore throat.

Reference! With reduced immunity, immunocorrective therapy will be required.

Factors that reduce children's immunity

The formation of immunity in children is influenced by external and internal factors. They can affect development both positively and negatively. On protective function In infants, the characteristics of intrauterine formation also influence.

Factors of reduced protection in infants:

• complicated childbirth;
• hereditary predisposition to various pathologies;
• severe pregnancy, bad habits at the mother's;
• disruption of the gastrointestinal tract;
• poor environmental situation;
• insufficient nutrition, deficiency or excess of nutrients;
• refusal of breast milk before 6 months of age;
• frequent use of medications;
• psychological trauma.

U older children Immunity can be affected by factors such as:

• nervous tension and stress;
• physical inactivity, sedentary lifestyle;
• poor nutrition;
• frequent hypothermia, exacerbation of allergies.

Reference! There are 5 critical stages in the formation of immune defense, and each will have its own factors that most affect the resistance of the body.

How immunity is formed in an infant

The formation of immunity begins during the period intrauterine development. By the 12th week, T-leukocytes appear in the body, the number of which increases greatly on the 5th day from birth. During the first months of life, the child is protected by maternal antibodies, and the body is not yet able to synthesize its own immunoglobulins. Only by the age of 3 does a child’s immunity become close to that of adults in terms of the number of type M antibodies.

To understand how the immunity of infants and older children is formed, one should consider its main periods. There are 5 of them in total, lasting from birth to adolescence - 12-15 years.

The main stages of the formation of immune defense

Important periods of life on which the characteristics of immunity in children will depend:

• First stage- from birth to 28 days of life.
• Second- from 3 months to six months of age.
• Third- from 2 years to 3 years.
• Fourth- 6-7 years.
• Fifth- adolescence up to 15 years.

First stage of development

The first important stage for the formation of immunity in a child is 28 days from birth. At this time, the newborn is protected by the mother’s antibodies; he has innate nonspecific immunity, while his own is just beginning to take shape. At this time, the body is most susceptible to diseases, especially those from which antibodies were not transferred from the mother. The innate immune system also provides protection against diseases that humans do not get.

Reference! To strengthen the child's immunity, it is important to maintain breastfeeding, as mother's milk becomes the main defense.

Second stage of development

From 3 months of age to 6 months In the baby's body, antibodies received from the mother are destroyed, and active immunity begins to form. The child is susceptible to acute respiratory infections viral diseases. Breasts are also prone to intestinal disorders, worms, pathologies of the respiratory system. The child may not receive antibodies from the mother to such pathologies as chickenpox, whooping cough, and rubella. In this case, the risk of severe course of these diseases is high.

Immunological memory has not yet been formed during this period. This becomes a factor in the re-development of infectious diseases. During this period the risk is high allergic reactions. Allergens can be food, pollen, dust mites and other substances.

Third

From 2 to 3 years the child begins to more actively contact others and explore the world. New pathogens enter the body. During this period, the immune system in children is not yet mature; the primary immune response predominates. There is a high risk of such disorders as helminthic infestations, stomatitis, respiratory diseases. The body is especially susceptible to bacterial and viral pathogens.

Fourth

From 6 years old there is already accumulated active immunity. Children under 7 years of age are susceptible to transition acute diseases into a chronic process. Parents should pay attention to any changes in health status in order to timely treatment before puberty begins, because then hormonal changes aggravate all existing pathologies. Children 6-7 years old are susceptible to allergic reactions.

Fifth

IN teenage years from 12 years old in girls and boys from 13-14 years old active hormonal changes begin. This affects health by exacerbation of chronic diseases. Hormonal changes are combined with a decrease in lymphoid organs. A teenager may need to have his tonsils (adenoids) removed, which are enlarged due to frequent illnesses and weak protection. The causative agents of the disease can be both viral and bacterial agents.

How to develop immunity in a child

By following individual recommendations from specialists during the development of children, you can help their normal growth, eliminating frequent health problems. You should start taking care of this during pregnancy. A woman needs to accept vitamin complexes, eat well, eliminate stressful situations.

How to increase the body's resistance to infectious pathogens:

• Emphasize on diet. Any product from the first feeding should be healthy, that is, contain vitamins. If the body does not receive enough nutrients, it will not be able to function fully, and therefore the immune system will also suffer from this.
• Give your child regularly, as recommended by your doctor. vitamin and mineral complexes.
• Observe daily regime, do exercises in the morning, and before going to bed take a walk fresh air. You need to immediately get used to one schedule. It is better to clarify in advance which mode is in kindergarten to prepare your baby for it. A change of environment, going to kindergarten and school is stress, and it affects the immune system. If you don’t have to suddenly change the regime, the child will tolerate it easier. In addition, before kindergarten and school, it is recommended to additionally give general strengthening, immunomodulating and vitamin complexes.
• Prepare the child psychologically to any unpleasant situations (going to the doctor, especially the dentist, moving, strangers in the house).
• Treat all diseases and consult a doctor when the first signs of illness appear. An important measure will be prevention of childhood infections by vaccination.

Important! Healthy sleep is important for the normal functioning of the defense mechanism.

Children should sleep longer than adults at night. Daytime nap is also important and should be taught according to the expected schedule in kindergarten. Full sleep helps improve immunity. The positive effect on immune cells performing exercises, properly hardening the body and psychological comfort.

Ways to test your immune system

They will help you find out what kind of immunity you have in order to improve it. special tests. The main one is an immunogram. A blood test for immunity can be taken at at will or as prescribed by a doctor.

An immunogram allows you to obtain the following information:

• amount of immunoglobulins;
• speed of phagocyte reaction to stimuli;
• functional ability of cytokines;
• rate of phagocytosis;
• leukocyte count;
• presence of allergies to antibodies.

If there are abnormalities in the immunogram, the doctor will prescribe treatment. After some time, the blood test is taken again. To obtain reliable results you need proper preparation for examination.

Preparing to donate blood:

• the doctor cancels some medications;
• foci of inflammation are eliminated (analysis is carried out a month after treatment);
• the day before the analysis you need to give up active physical games and sports.

When to get tested

The main indications for a blood test for a child’s immunity will be:

• primary immunodeficiencies;
• P acquired immunodeficiencies;
• frequent viral diseases;
• poor response to treatment.

Signs of immunodeficiency for which you need to be examined:

• often recurrent infectious and purulent diseases;
• frequent oral candidiasis;
• severe course of dermatological diseases.

Reference! Tests may be prescribed when a child is often sick without apparent reason, and when there is resistance to drugs.

White blood cell count in a child

If the number of leukocytes is low, it is important to check the child’s immunity. Normal indicators will be from 6.5 to 13.8 in a month-old baby, from 5.5 to 12.5 in six months and from one to 6 years old - from 6 to 12. When immunity becomes close to an adult, the indicator begins to vary from 4.5 to 9.

What is dangerous about a decrease in the number of leukocytes:

• development of anemia;
• thrombocytopenia leading to bleeding;
• stomatitis with severe course (ulcers, necrosis);
• liver pathologies, when the infection enters the organ;
• agranulocytosis - tissue necrosis occurs, ulcers appear;
• bacterial pneumonia.

You can increase the level of leukocytes with a properly selected diet. The child needs to be given more citrus fruits, berries, fresh vegetables. Beetroot, walnuts, seafood, chicken eggs. If tolerance is normal, it is recommended to give more dairy and fermented milk products. ethnoscience For this purpose, he suggests using oat decoctions, honey with pollen, and wormwood infusion.

When a child seems lethargic from birth, eats poorly, shows no interest in the world around him, and is often sick, you should consult an immunologist and pediatrician. Experts will give recommendations to strengthen your defenses, which will improve your overall well-being.

The formation of immunity in a child has 5 stages, each with its own characteristics, knowing which parents can provide for everything and avoid many problems.

Development of the immune system in children

Although the development of the immune system in children begins in utero, it receives a powerful boost from the moment of the first attachment to the mother’s breast immediately after birth. The first stage is perhaps the most difficult - 28 days. In fact, during this period he lives due to the transferred antibodies 1 if he used colostrum, i.e. if his mother breastfed him in the first hours and first three days after birth. But representatives of the older and middle generations are unlikely to have experienced it - this is colostrum. Because for more than 70 years in European countries, including Russia, unfortunately, children were deprived of this miracle product invented by nature. Now in maternity hospitals it is immediately handed over to the mother so that he falls to the breast and sucks these precious drops of colostrum. In order to take all the information about immunity from mom.

However, even without receiving colostrum, the child subsequently receives antibodies along with mother's milk. And why does a newborn have such passive immunity during the first 28 days? If you ask your mother, is the newborn child your own or someone else’s? Of course, dear, flesh of his own flesh. Look - he inherited his mother's genes. But also the father's genes. Therefore, biologically, the child represents a foreign organism. Why does the fetus develop inside the placenta? So that the mother's blood does not come into contact with the blood of the fetus. Otherwise there will be rejection. Since the child defended himself and all of him functional systems were aimed at resisting and not feeling the antigenic structure of the mother - he had very high suppressor activity. Those. activity to suppress the immune system.

Why do they say in the East that a woman after giving birth for 40 days should lift the biggest thing - a spoon, and nothing else. During this period, the woman gives the child immune structure. She wants to sleep a lot, just like a baby - and let her sleep so that the milk is full and active. If during this period she physically exerts herself greatly, this leads to fatigue and the milk does not produce its structure properly. As a result, every second child is born with allergies. The scourge of big cities.

Second period. How to boost the immunity of a 3 year old child

The second period in a child is from 2 to 3 years old, a period of pulmonary (relating to the respiratory organs) inactivity. And it coincides with the first period of stubbornness. The child already realizes that he is the head of the family, that everything is possible for him. And this is where powerful tensions arise. It is enough to observe the behavior of parents towards their young children. The question naturally arises - why is it not customary for us to raise children of this age like in the East: in Japan, in Korea? Where a child under 5 years old can do anything - even stand on his head. And we have? Anything that goes wrong is immediately “impossible”, a slap on the face (okay, if it hits the butt). Often.

The Secret to Immune Health

How to boost the immunity of a 3 year old child? It is known that if a child smiles, then he is resilient. One smile and a child's laughter give him more immune health than any drug. It has been clearly proven that if you laugh for one minute, it is equivalent to forty minutes of yoga. So which is better? Laugh heartily for one minute?! So is the child. But it's not always that simple. If a child is already sick with something, he most likely is not laughing. This is where a teacher for the immune system - Transfer Factor - will help. At the first symptoms of a cold, give your baby half a capsule every hour - within 24 hours the symptoms of the disease should go away. Then the child’s smile will be natural and he will be able to cope on his own.

Cross blood in a child

The child has the 2nd, 3rd, 4th and 5th periods. Notice how smart the immune system works. On the fifth day, the child experiences a crossover, the so-called physiological blood crossover, when the number of lymphocytes increases sharply, and segmented neutrophils sharply decrease. This is the first cross. The second cross will occur at 5 years of age. And until the age of five, the child has very high lymphocytosis. This is the norm for him.

White blood cell count in a child

And sometimes, since the number of lymphocytes is a powerful reflection of the stress response, the child has a slightly different relationship here. In an adult it is very clear - if the lymphocyte count is more than 43%, then the person is overactivated. And if it’s less than 20%, then under stress it’s also a bad reaction. Those. lymphocytes are always a mirror of your mood, your adaptive capabilities. And from your analyzes you can very clearly see if your child is over 5 years old - whether he is under stress or not. The pediatrician will always make you want a blood test - and you can read it yourself.

Acute stress is characterized by leukocytosis and a decrease in lymphocytes, while in chronic stress the number of leukocytes will be normal and lymphocytes will be low. And the most difficult thing is for a child over 5 years old, when his reaction is more than 43 lymphocytes. In this case, Transfer Factor is a very big help.

The third period of immunity formation. Prevention of helminthic infestations

The fourth period of development of immunity. Puberty

The child has reached next period- period of puberty. For boys it starts from 12 to 16 years of age. For girls, this is usually from 9-11 years old, today already from 9. Previously it was from 14, but even now there remains such a category of people - from 14.

And myself a hormonal surge inhibits the activity of the immune system. This is why girls often develop acne vulgaris - youthful acne, both in boys and girls. Well, it’s not so scary for young men. And at this moment it is important that the child receives increased doses of the “teacher” - Transfer Factor. Because hormones themselves inhibit activity. Hormonal, immune, nervous - all these systems are interconnected. And therefore, during this period, those hidden, latent diseases that once existed in childhood arise. If a child under one year old has had some kind of bronchopulmonary infection, then the likelihood of him developing bronchopulmonary pathology in the future is very high. Especially during puberty. That's why children with bronchial asthma/link/ during this period of their lives - a huge number.

The fifth stage of immunity formation. Should tonsils and adenoids be removed?

The fifth stage of immunity formation is from 14 to 16 years, the last period when, as a rule, it ends puberty, and the body begins to grow even faster. There is a hyper-reaction to various influences. Sometimes, if they haven’t been removed before, they have to have their tonsils removed or their adenoids removed. By this age, the adenoids may already be so large that the child practically does not breathe. Do not rush to remove these organs - this is protection. Let your child suck on Transfer Factor Classic - chew and suck - everything will go away in 2-3 months. An additional enhancing effect is to instill thuja oil into the nose. The child will close his mouth and breathe with his mouth closed. During this period, it is advisable to support the immune system, which reacts too actively. It just needs to be toned down a little. Can you name at least one that has suppressor activity? Those. activities aimed at containing active immunity. But in fact, the most powerful suppressor link is Transfer Factor - the only product that affects all parts of the immune system. That's why he is a teacher - where you need to direct, and where you need to restrain. It is very important.

1 Antibodies are special substances that are used by the immune system to recognize and destroy foreign objects - bacteria, viruses, etc.

2 Enzymatic digestion - the assimilation of food thanks to enzymes - substances that direct and accelerate metabolism in the body.

Question answer

06/03/2014. Alexandra.
Question: Youngest son almost 5 years. I have been giving him TF classic since January, 3 capsules a day. The immune system has become much healthier; even if I caught some kind of virus, everything passed much faster, without fever, slight runny nose and cough... What is the further treatment for a child of his age, if there is a delay in speech development due to oxygen starvation during childbirth ( natural childbirth)? The neurologist diagnosed "Pseudobulbar dysarthria".
Answer: We need to continue in the same spirit. And if it is possible to give more (up to 6 capsules per day) - only better. Or another, more effective regimen: add Transfer Factor Advance (Classic - 3 capsules per day and - 2 capsules per day).
As for the diagnosis, there is one wonderful specialist in childhood diseases and in particular those related to oxygen starvation - Aleksey Yaroslavovich Chizhov - he knows a lot about Transfer Factor and he also treated the children." Mountain air"with great success.