Physiological leukocyte crossover. PF34. Physiological crossover is a change in the ratio between. What is the leukocyte formula and what indicators are studied in it

Description of work with demonstration drugs:

1. Human blood smear. Env. according to Romanovsky-Giemsa, uv. immersion.

In human blood smears under immersion, consider in more detail the structural features of eosinophilic granulocyte, basophilic granulocyte, and monocyte.

After working with the drugs, students decide situational tasks on this topic:

1. The patient was mistakenly injected into a vein hypotonic solution. What changes can happen to red blood cells in the blood?

2. A patient was accidentally injected into a vein with a 1.5% NaCl solution. What can happen to red blood cells in the blood?

3. In the leukocyte formula of the blood of an adult patient, the percentage of young and band neutrophils is increased and the content of segmented neutrophils is reduced. What is this condition called? leukocyte formula?

4. The leukocyte formula of the patient’s blood indicates eosinophilia. What is it? What might these changes in the blood indicate?

5. A human blood smear shows a large round cell with slightly basophilic cytoplasm and a bean-shaped nucleus. Name this cell.

6. The child has a helminthic infestation. What changes in the leukocyte formula should be expected?

7. In the leukocyte formula healthy person contains 65% lymphocytes and 25% neutrophils. What is the possible age this person?

8. In the patient’s leukocyte formula, the percentage of segmented neutrophils is increased and young and band neutrophils have disappeared. What is it called this state leukocyte formula?

Note for pediatric students:

Red blood cells: in newborns there is an increased content of erythrocytes (6-7x10 12 / l), anisocytosis, poikilocytosis, reticulocytosis, polychromatophilic normocytes are detected. By 10-14 days it is equal to the adult figures. Subsequently, there is a decrease in the number of red blood cells with minimal indicators at 3-6 months of life (physiological anemia). During puberty, the number of red blood cells reaches the adult norm.

Hemoglobin: in newborns, the Hb content is increased to 110-115% of the adult norm. The blood of children of the 1st year of life is characterized by a decrease in hemoglobin content. By the age of 2, hemoglobin rises again and its content gradually returns to normal by the age of 15.

Leukocytes: their number in the blood of a newborn is increased and reaches 10-30x10 9 /l. Within 2 weeks after birth, their number drops to 9-15x10 9 / l. The number of leukocytes reaches a level by the age of 14-15 that remains in an adult. The ratio of the number of neutrophils and lymphocytes in a newborn is the same as in adults. In subsequent periods, the content of neutrophils decreases, and lymphocytes increase, and thus, by 4-6 days the number of these types of leukocytes is equalized ( first physiological crossover of leukocytes). A further increase in the number of lymphocytes and a decrease in neutrophils lead to the fact that at 1-3 years of life the percentage of lymphocytes is 65 and neutrophils 25. A new decrease in the number of lymphocytes and an increase in neutrophils lead to an equalization of both indicators in 4-6 year old children ( second physiological cross). A gradual decrease in the content of lymphocytes and an increase in neutrophils continues until puberty, when the number of these types of leukocytes reaches the adult norm.

Topics of abstract messages:

1. Functional significance, origin and derivatives of mesenchyme.

2. Comparative morpho functional characteristic erythrocytes and platelets of human and frog blood.

3. Morphofunctional changes in leukocytes in connective tissue. The concept of the mononuclear phagocyte system.

4. Morphofunctional characteristics of lymph.

At the end of the laboratory session, students must submit and defend the protocol, find out the homework assignment to prepare for the next lesson. When defending the protocol, the student answers the teacher’s questions.

References:

Main:

1. Almazov I.V., Sutulov L.S. Atlas of histology and embryology. – M., Medicine. – 1978. - P. 128-136.

2. Bykov V. L. Cytology and general histology. – SPb.: SOTIS. – 2000 (2002, 2007). - pp. 160-217.

3. Histology: a textbook for honey. universities / ed. Yu. I. Afanasyev, S. L. Kuznetsov, N. A. Yurina. - M.: Medicine, 2001 (2006). - pp. 155-198.

4. Kuznetsov S. L. Histology, cytology and embryology: a textbook for honey. universities / S. L. Kuznetsov, N. N. Mushkambarov. -M.: Med. information agency, 2007. - pp. 127-143.

5. Lecture on the topic “Mesenchyme. Blood".

Additional:

1. Kuznetsov S. L., Mushkambarov N. N., Goryachkina V. L. Atlas of histology, cytology and embryology. - M., MIA. – 2002. - P. 68-71.

2. Novikov V. D. Histology, cytology, embryology: Handbook / V. D. Novikov, G. V. Pravotorov. -M.: YuKEA, 2003. -336 p.

3. Guide to histology. Ed. R. K. Danilova, V. L. Bykova. – St. Petersburg, SpetsLit, 2001. - P. 453-535.

4. Test assignments for the histology course / Yu. I. Sklyanov, G. V. Pravotorov, S. V. Mashak [etc.]; edited by Prof. Yu. I. Sklyanova. - Novosibirsk: Sibmedizdat NSMU, 2010. - P. 33-37.

5. Ham E., Cormack D. Histology. – M.: Mir. - 1983. - T.2. - P.106-152.

6. Yushkantsev S.I., Bykov V.L. Histology, cytology and embryology. Brief atlas: Textbook. 2nd ed., revised. and additional - St. Petersburg: Publishing house "P-2", 2007. - pp. 22-23.

The greatest changes in the leukocyte formula are observed in the content of neutrophils and lymphocytes. The remaining indicators do not differ significantly from those of adults.

Classification of leukocytes

Development timeframe:

I. Newborns:

· neutrophils 65-75%;

· lymphocytes 20-35%;

II. 4th day - first physiological crossover:

· neutrophils 45%;

· lymphocytes 45%;

III. 2 years:

· neutrophils 25%;

· lymphocytes 65%;

IV. 4 years - second physiological crossover:

· neutrophils 45%;

· lymphocytes 45%;

V. 14-17 years:

· neutrophils 65-75%;

· lymphocytes 20-35%.

6. Lymph consists of lymphoplasm and shaped elements, mainly lymphocytes (98%), as well as monocytes, neutrophils, and sometimes erythrocytes. Lymphoplasma is formed through the penetration (drainage) of tissue fluid into the lymphatic capillaries, and then is discharged through lymphatic vessels of various sizes and flows into the venous system. Along the way, lymph passes through lymph nodes, in which it is cleared of exogenous and endogenous particles, and is also enriched with lymphocytes.

Based on its qualitative composition, lymph is divided into:

peripheral lymph - up to lymph nodes;

· intermediate lymph - after the lymph nodes;

· central lymph - thoracic duct lymph.

In the area of the lymph nodes, not only the formation of lymphocytes occurs, but also the migration of lymphocytes from the blood into the lymph, and then with the flow of lymph they again enter the blood, and so on. These lymphocytes make up recirculating pool of lymphocytes.

Functions of lymph:

tissue drainage;

· enrichment with lymphocytes;

· cleansing the lymph from exogenous and endogenous substances.

LECTURE 7. Hematopoiesis

1. Types of hematopoiesis

2. Theories of hematopoiesis

3. T-lymphocytopoiesis

4. B-lymphocytopoiesis

1. Hematopoiesis(hemocytopoiesis) the process of formation of blood cells.

There are two types of hematopoiesis:

myeloid hematopoiesis:

· erythropoiesis;

· granulocytopoiesis;

thrombocytopoiesis;

· monocytopoiesis.

lymphoid hematopoiesis:

· T-lymphocytopoiesis;

· B-lymphocytopoiesis.

In addition, hematopoiesis is divided into two periods:

· embryonic;

· postembryonic.

Embryonic period hematopoiesis leads to the formation of blood as tissue and therefore represents blood histogenesis. Postembryonic hematopoiesis is a process physiological regeneration blood as tissue.

The embryonic period of hematopoiesis occurs in stages, replacing different hematopoietic organs. In accordance with this embryonic hematopoiesis is divided into three stages:

· yolk;

· hepato-thymus-lienal;

· medullo-thymus-lymphoid.

Yolk stage is carried out in the mesenchyme of the yolk sac, starting from the 2-3rd week of embryogenesis, from the 4th week it decreases and by the end of the 3rd month it completely stops. The process of hematopoiesis at this stage is carried out as follows, first in the mesenchyme of the yolk sac, as a result of proliferation of mesenchymal cells, “ blood islands" representing focal accumulations of branched mesenchymal cells. Then differentiation of these cells occurs in two directions ( divergent differentiation):

· the peripheral cells of the islet are flattened, interconnected and form the endothelial lining of the blood vessel;

· the central cells round up and turn into stem cells.

From these cells in the vessels, that is, intravascularly the process of formation of primary erythrocytes (erythroblasts, megaloblasts) begins. However, some stem cells end up outside the blood vessels ( extravascular) and granular leukocytes begin to develop from them, which then migrate into the vessels.

Most important points yolk stage are:

formation of blood stem cells;

· formation of primary blood vessels.

Somewhat later (at the 3rd week), vessels begin to form in the mesenchyme of the body of the embryo, but they are empty slit-like formations. Quite soon, the vessels of the yolk sac connect with the vessels of the body of the embryo; through these vessels, stem cells migrate into the body of the embryo and populate the anlages of future hematopoietic organs (primarily the liver), in which hematopoiesis then occurs.

Hepato-thymus-splenic the stage of hematopoiesis occurs initially in the liver, somewhat later in the thymus (thymus gland), and then in the spleen. In the liver, mainly myeloid hematopoiesis occurs (only extravascularly), starting from the 5th week until the end of the 5th month, and then gradually decreases and completely stops by the end of embryogenesis. The thymus is formed at the 7-8th week, and a little later T-lymphocytopoiesis begins in it, which continues until the end of embryogenesis, and then in the postnatal period until its involution (at 25-30 years). The process of formation of T-lymphocytes at this moment is called antigen independent differentiation. The spleen is formed in the 4th week, from 7-8 weeks it is populated with stem cells and universal hematopoiesis begins in it, that is, myelolymphopoiesis. Hematopoiesis in the spleen is especially active from the 5th to 7th months of intrauterine development of the fetus, and then myeloid hematopoiesis is gradually suppressed and by the end of embryogenesis (in humans) it completely stops. Lymphoid hematopoiesis remains in the spleen until the end of embryogenesis, and then in the postembryonic period.

Consequently, hematopoiesis at the second stage in the named organs occurs almost simultaneously, only extravascularly, but its intensity and qualitative composition are different in different organs.

Medullo-thymus-lymphoid stage of hematopoiesis. The formation of red bone marrow begins from the 2nd month, hematopoiesis in it begins from the 4th month, and from the 6th month it is the main organ of myeloid and partially lymphoid hematopoiesis, that is, it is universal hematopoietic organ. At the same time, lymphoid hematopoiesis occurs in the thymus, spleen and lymph nodes. If the red bone marrow is not able to satisfy the increased need for formed elements of blood (during bleeding), then the hematopoietic activity of the liver and spleen may become more active - extramedullary hematopoiesis.

Postembryonic period of hematopoiesis - carried out in red bone marrow and lymphoid organs (thymus, spleen, lymph nodes, tonsils, lymphoid follicles).

The essence of the process of hematopoiesis is the proliferation and step-by-step differentiation of stem cells into mature blood cells.

2. Theories of hematopoiesis:

· unitary theory (A. A. Maksimov, 1909) - all formed elements of blood develop from a single precursor of a stem cell;

· the dualistic theory provides for two sources of hematopoiesis, myeloid and lymphoid;

· polyphyletic theory provides for each shaped element its own source of development.

Currently, the unitary theory of hematopoiesis is generally accepted, on the basis of which a hematopoiesis scheme has been developed (I. L. Chertkov and A. I. Vorobyov, 1973).

In the process of step-by-step differentiation of stem cells into mature blood cells, intermediate types of cells are formed in each row of hematopoiesis, which constitute cell classes in the hematopoiesis scheme. In total, 6 classes of cells are distinguished in the hematopoietic scheme:

· Class 1 - stem cells;

· Class 2 - semi-stem cells;

· Class 3 - unipotent cells;

· 4th class - blast cells;

· Class 5 - maturing cells;

· 6th grade - mature shaped elements.

Morphological and functional characteristics of cells of various classes of the hematopoietic circuit.

1st class- a pluripotent stem cell capable of maintaining its population. Its morphology corresponds to a small lymphocyte and is pluripotent, that is, capable of differentiating into any formed element of blood. The direction of stem cell differentiation is determined by the level of this formed element in the blood, as well as the influence of the microenvironment of stem cells - the inductive influence of stromal cells of the bone marrow or other hematopoietic organ. Maintaining the size of the stem cell population is ensured by the fact that after mitosis of the stem cell, one of the daughter cells takes the path of differentiation, and the other takes on the morphology of a small lymphocyte and is a stem cell. Stem cells rarely divide (once every six months), 80% of stem cells are in a state of rest and only 20% are in mitosis and subsequent differentiation. In the process of proliferation, each stem cell forms a group or clone of cells and therefore stem cells in the literature are often called colony-forming units- CFU.

2nd grade- semi-stem, limited pluripotent (or partially committed) precursor cells of myelopoiesis and lymphopoiesis. They have the morphology of a small lymphocyte. Each of them produces a clone of cells, but only myeloid or lymphoid. They divide more often (every 3-4 weeks) and also maintain the size of their population.

3rd grade- unipotent poetin-sensitive precursor cells of their hematopoietic series. Their morphology also corresponds to a small lymphocyte. Able to differentiate into only one type of shaped element. They divide frequently, but the descendants of these cells some enter the path of differentiation, while others maintain the population size of this class. The frequency of division of these cells and the ability to differentiate further depends on the content of special biologically active substances in the blood - poetins, specific for each series of hematopoiesis (erythropoietins, thrombopoietins and others).

The first three classes of cells are combined into a class of morphologically unidentifiable cells, since they all have the morphology of a small lymphocyte, but their developmental potencies are different.

4th grade- blast (young) cells or blasts (erythroblasts, lymphoblasts, etc.). They differ in morphology from both the three preceding and subsequent classes of cells. These cells are large, have a large loose (euchromatin) nucleus with 2-4 nucleoli, the cytoplasm is basophilic due to a large number of free ribosomes. They divide frequently, but the daughter cells all embark on the path of further differentiation. Based on their cytochemical properties, blasts of different hematopoietic series can be identified.

5th grade- a class of maturing cells characteristic of their hematopoietic series. In this class there can be several varieties of transitional cells - from one (prolymphocyte, promonocyte) to five in the erythrocyte series. Some maturing cells in small numbers can enter the peripheral blood (for example, reticulocytes, young and band granulocytes).

6th grade- mature blood cells. However, it should be noted that only erythrocytes, platelets and segmented granulocytes are mature terminal differentiated cells or their fragments. Monocytes are not terminally differentiated cells. Leaving the bloodstream, they differentiate into terminal cells - macrophages. When lymphocytes encounter antigens, they turn into blasts and divide again.

The totality of cells that make up the line of differentiation of a stem cell into a certain shaped element form it differon or histological series. For example, the erythrocyte differential is composed of: stem cell, semi-stem myelopoiesis precursor cell, unipotent erythropoietin-sensitive cell, erythroblast, maturing pronormocyte cells, basophilic normocyte, polychromatophilic normocyte, oxyphilic normocyte, reticulocyte, erythrocyte. In the process of maturation of erythrocytes in class 5, the following occurs: synthesis and accumulation of hemoglobin, reduction of organelles, reduction of the nucleus. Normally, the replenishment of erythrocytes is carried out mainly due to the division and differentiation of maturing cells of pronormocytes, basophilic and polychromatophilic normocytes. This type of hematopoiesis is called homoplastic hematopoiesis. In case of severe blood loss, the replenishment of red blood cells is ensured not only by the increased division of maturing cells, but also by cells of classes 4, 3, 2 and even class 1, a heteroplastic type of hematopoiesis that precedes reparative blood regeneration.

3. Unlike myelopoiesis, lymphocytopoiesis in the embryonic and postembryonic periods it is carried out in stages, replacing different lymphoid organs. In T- and B-lymphocytopoiesis there are three stages:

· bone marrow stage;

· the stage of antigen-independent differentiation, carried out in the central immune organs;

· the stage of antigen-dependent differentiation, carried out in peripheral lymphoid organs.

At the first stage of differentiation, stem cells form precursor cells of T- and B-lymphocytopoiesis, respectively. At the second stage, lymphocytes are formed that can only recognize antigens. At the third stage, effector cells are formed from the cells of the second stage, capable of destroying and neutralizing the antigen.

The process of development of T- and B-lymphocytes has both general patterns and significant features and therefore is subject to separate consideration.

The first stage of T-lymphocytopoiesis carried out in lymphoid tissue red bone marrow, where the following classes of cells are formed:

· Class 1 - stem cells;

· Class 2 - semi-stem precursor cells of lymphocytopoiesis;

· Class 3 - unipotent T-poietin-sensitive precursor cells of T-lymphocytopoiesis, these cells migrate into the bloodstream and reach the thymus with the blood.

Second stage- the stage of antigen-independent differentiation occurs in the thymus cortex. Here the further process of T-lymphocytopoiesis continues. Biologically influenced active substance thymosin, secreted by stromal cells, unipotent cells turn into T-lymphoblasts - class 4, then into T-prolymphocytes - class 5, and the latter into T-lymphocytes - class 6. In the thymus, three cells develop independently from unipotent cells subpopulations T-lymphocytes: killers, helpers and suppressors. In the thymus cortex, all of the listed subpopulations of T-lymphocytes acquire different receptors for various antigenic substances (the mechanism of formation of T-receptors remains unclear), but the antigens themselves do not enter the thymus. Protection of T-lymphocytopoiesis from foreign antigenic substances is achieved two mechanisms:

· the presence of a special blood-thymus barrier in the thymus;

· lack of lymphatic vessels in the thymus.

As a result of the second stage, receptor(afferent or T0-) T-lymphocytes - killers, helpers, suppressors. At the same time, lymphocytes in each of the subpopulations differ from each other by different receptors, however, there are also cell clones that have the same receptors. T-lymphocytes that have receptors for their own antigens are formed in the thymus, but such cells are destroyed here by macrophages. T-receptor lymphocytes (killers, helpers and suppressors) formed in the cortex, without entering the medulla, penetrate into the vascular bed and are carried by the bloodstream into the peripheral lymphoid organs.

Third stage- the stage of antigen-dependent differentiation is carried out in the T-zones of peripheral lymphoid organs - lymph nodes, spleen and others, where conditions are created for the antigen to meet a T-lymphocyte (killer, helper or suppressor) that has a receptor for this antigen. However, in most cases, the antigen does not act directly on the lymphocyte, but indirectly - through macrophage, that is, first the macrophage phagocytizes the antigen, partially breaks it down intracellularly, and then the active chemical groups of the antigen - antigenic determinants are brought to the surface of the cytolemma, contributing to their concentration and activation. Only then are these determinants transmitted by macrophages to the corresponding receptors of different subpopulations of lymphocytes. Under the influence of the corresponding antigen, the T-lymphocyte is activated, changes its morphology and turns into a T-lymphoblast, or rather into T-immunoblast, since this is no longer a class 4 cell (formed in the thymus), but a cell arising from a lymphocyte under the influence of an antigen.

The process of converting a T-lymphocyte into a T-immunoblast is called a reaction blast transformation. After this, the T-immunoblast, arising from the T-receptor killer, helper or suppressor, proliferates and forms a clone of cells. T-killer immunoblast produces a clone of cells, among which are:

· T-memory (killers);

· Killer T-cells or cytotoxic lymphocytes, which are effector cells that provide cellular immunity, that is, the body’s protection from foreign and genetically modified own cells.

After the first meeting of a foreign cell with a receptor T-lymphocyte, a primary immune response develops - blast transformation, proliferation, formation of killer T-cells and their destruction of the foreign cell. Memory T cells, when encountering the same antigen again, provide a secondary immune response using the same mechanism, which is faster and stronger than the primary one.

The T-helper immunoblast produces a clone of cells, among which there are T-memory cells and T-helper cells that secrete the mediator - lymphokine, stimulating humoral immunity - an inducer of immunopoiesis. The mechanism of formation of T-suppressors is similar, the lymphokine of which inhibits the humoral response.

Thus, as a result of the third stage of T-lymphocytopoiesis, effector cells of cellular immunity (T-killers), regulatory cells of humoral immunity (T-helpers and T-suppressors), as well as T-memories of all populations of T-lymphocytes are formed, which, when they meet again with the same antigen will again provide immune protection the body in the form of a secondary immune response. Providing cellular immunity is considered two destruction mechanisms killer antigenic cells:

· contact interaction - “the kiss of death”, with the destruction of a section of the cytolemma of the target cell;

· distant interaction - through the release of cytotoxic factors that act on the target cell gradually and for a long time.

4. The first stage of B-lymphocytopoiesis carried out in the red bone marrow, where they are formed the following cell classes:

· Class 1 - stem cells;

· Class 2 - semi-stem precursor cells of lymphopoiesis;

· Class 3 - unipotent B-poietin-sensitive precursor cells of B-lymphocytopoiesis.

Second stage antigen-independent differentiation in birds is carried out in a special central lymphoid organ - the bursa of Fabricius. Mammals and humans lack such an organ, and its analogue has not been precisely established. Most researchers believe that the second stage also takes place in the red bone marrow, where B-lymphoblasts (class 4) are formed from unipotent B cells, then B-prolymphocytes (class 5) and lymphocytes (class 6) (receptor or B0). During the second stage, B lymphocytes acquire a variety of receptors for antigens. It has been established that the receptors are represented by immunoglobulin proteins, which are synthesized in the maturing B-lymphocytes themselves, and then brought to the surface and integrated into the plasmalemma. The terminal chemical groups of these receptors are different, and this is what explains the specificity of their perception of certain antigenic determinants of different antigens.

Third stage- antigen-dependent differentiation is carried out in the B-zones of peripheral lymphoid organs (lymph nodes, spleen and others) where the antigen meets the corresponding B-receptor lymphocyte, its subsequent activation and transformation into an immunoblast. However, this occurs only with the participation of additional cells - macrophage, T-helper, and possibly T-suppressor, that is, to activate the B-lymphocyte, cooperation of the following cells is necessary: B-receptor lymphocyte, macrophage, T-helper (T-suppressor), as well as humoral antigen (bacteria, virus, protein, polysaccharide and others). The interaction process takes place in following sequence:

· macrophage phagocytoses the antigen and brings determinants to the surface;

· influences B-lymphocyte receptors with antigenic determinants;

· affects the T-helper and T-suppressor receptors with the same determinants.

The influence of an antigenic stimulus on a B lymphocyte is not enough for its blast transformation. This occurs only after the activation of the T helper cell and the release of activating lymphokine. After such an additional stimulus, a blast transformation reaction occurs, that is, the transformation of a B-lymphocyte into an immunoblast, which is called plasmablast, since as a result of proliferation of the immunoblast, a clone of cells is formed, among which are distinguished:

· V-memory;

Plasmocytes, which are effector cells of humoral immunity.

These cells synthesize and release into the blood or lymph immunoglobulins(antibodies) different classes, which interact with antigens and form antigen-antibody complexes (immune complexes) and thereby neutralize antigens. The immune complexes are then phagocytosed by neutrophils or macrophages.

However, antigen-activated B lymphocytes are capable of synthesizing small amounts of nonspecific immunoglobulins themselves. Under the influence of T-helper lymphokines, firstly, the transformation of B-lymphocytes into plasmacytes occurs, secondly, the synthesis of nonspecific immunoglobulins is replaced by specific ones, and thirdly, the synthesis and release of immunoglobulins by plasmacytes is stimulated. T-suppressors are activated by the same antigens and secrete lymphokine, which inhibits the formation of plasma cells and their synthesis of immunoglobulins until they completely stop. The combined effect of T-helper and T-suppressor lymphokines on the activated B-lymphocyte regulates the intensity of humoral immunity. Complete suppression of the immune system is called tolerance or unresponsiveness, that is, the absence of an immune response to the antigen. It can be caused by both preferential stimulation of T-suppressor antigens and inhibition of T-helper function or death of T-helper cells (for example, in AIDS).

In a newborn, the percentage of lymphocytes, gradually increasing, reaches 50-60 by the 5th day, and the percentage of neutrophils by the same time gradually decreases to 35-47.

The number of neutrophils and lymphocytes in different periods of childhood (in percentage): a - first crossover; b - second cross.

If we depict changes in the number of neutrophils and lymphocytes in the form of curves (Fig.), then approximately between the 3-5th day there is an intersection of the curves - the so-called first crossover. By the end of the first month of life, the child’s leukocyte formula is established, characteristic of the entire first year of life. The leukocyte formula of infants is somewhat unstable; it is relatively easily disrupted by severe crying and restlessness of the child, sudden changes in diet, cooling and overheating, and especially by various diseases.

Subsequently, in the 3-6th year of life, the number of lymphocytes decreases significantly and the number of neutrophils increases. The corresponding curves of neutrophils and lymphocytes cross again - the second cross. At the age of 14-15 years, the leukocyte formula of children almost completely approaches the leukocyte formula of adults.

The leukocyte formula in children naturally changes with age. The relative number of neutrophils at birth ranges from 51 to 72%, increases during the first hours of life, then decreases quite quickly (Table 2). The number of lymphocytes at birth ranges from 16 to 34%, by the end of the second week of life it reaches an average of 55%. At the age of about 5-6 days, the curves of neutrophils and lymphocytes intersect - this is the so-called first crossover (Fig. 2), which occurs during the first week of life from the 2-3rd to the 6-7th day. Basophilic leukocytes in newborns are often completely absent. The number of monocytes at birth ranges from 6.5 to 11%, and at the end of the neonatal period - from 8.5 to 14%. The number of plasma cells does not exceed 0.26-0.5%. In children in the first days of life, there is a clear shift of neutrophils to the left according to Schilling, almost leveling off by the end of the first week of life. In newborns and throughout the first year of life, there is an unequal size of lymphocytes: the main mass is made up of medium lymphocytes, there are slightly fewer small ones, and there are always 2-5% of large lymphocytes.

Table 2. Leukocyte formula of a newborn (according to A.F. Tour, in%)

Rice. 2. The first and second intersections of the curves of neutrophils and lymphocytes (according to A.F. Tour). Roman numerals indicate crossover options: 1 - according to Lippmann; II - according to Zibordi; III - according to Carstanien; IV - according to N.P. Gundobin; V - according to Rabinovich.

By the end of the first month of life, the child has established a leukocyte formula characteristic of the first year of life (Table 3). It is dominated by lymphocytes; There is always a moderate shift of neutrophils to the left, moderate monocytosis and an almost constant presence of plasma cells in the peripheral blood. Percentages between separate forms white blood cells in infants can fluctuate within very wide limits.

Leukocyte formula of children aged 1 month to 15 years (according to A.F. Tour, in%)

The leukocyte formula of infants is somewhat unstable; it is relatively easily disrupted by severe crying and restlessness of the child, sudden changes in diet, cooling and overheating, and especially by various diseases.

Sometimes already by the end of the first year of life, but more often in the second year there is a certain tendency towards a relative and absolute decrease in the number of lymphocytes and an increase in the number of neutrophils; in the following years of life, this change in the ratio between lymphocytes and neutrophils is revealed more sharply, and, according to A.F. Tour, at the age of 5-7 years their number becomes the same (“second cross” of the curve of neutrophils and lymphocytes).

During school years, the number of neutrophils continues to increase, and the number of lymphocytes decreases, the number of monocytes decreases somewhat, and plasma cells almost completely disappear. At the age of 14-15 years, the leukocyte formula in children is almost completely similar to that of adults (Table 3).

Correct assessment of the leukocyte formula in diseases has great value and is possible taking into account its characteristics determined by the age of the child.

LEUKOCYTE CROSSING

(RULE OF FOUR FOURS)

65% lymphocyte blood profile

4 days 1 year 4 years age

Figure 12. Leukocyte crossover.

In a newborn, the percentage of neutrophils and lymphocytes is the same as in an adult. Subsequently, the content of neutrophils decreases, and the content of lymphocytes increases, so that by 3-4 days their number is equalized (44%). This phenomenon is called first physiological (leukocyte) crossover. Subsequently, the number of neutrophils continues to decrease and by 1-2 years reaches 25%. At the same age, the number of lymphocytes is 65%, that is, at this age a lymphocytic blood profile is observed. For next years the number of neutrophils gradually increases, and the number of lymphocytes decreases, so that in 4-year-old children these indicators are equalized again (44%) - second physiological (leukocyte) crossover. The number of neutrophils continues to increase, and the number of lymphocytes continues to decrease, and by the age of 14 these indicators correspond to those of an adult, that is, a neutrophilic blood profile is observed.

Lymph(from the Greek lympha – pure moisture, spring water) – biological fluid, formed from interstitial (tissue) fluid, passing through the system of lymphatic vessels through a chain of lymph nodes (in which it is cleansed and enriched with formed elements) and through the thoracic duct into the blood.

Mechanism of lymph formation associated with the filtration of plasma from the blood capillaries into the interstitial space, resulting in the formation of interstitial (tissue) fluid. U young man with a body weight of 70 kg, the interstitial space contains about 10.5 liters of fluid. This fluid is partially reabsorbed into the blood and partially enters the lymphatic capillaries, forming lymph. The formation of lymph is facilitated by increased hydrostatic pressure in the interstitial space and differences in oncotic pressure between blood vessels and interstitial fluid (ensuring the daily flow of proteins from the blood into the tissue fluid). These proteins through lymphatic system completely return to the blood.

Lymph volume in the human body is, on average, 1-2 liters.

· peripheral lymph(flowing from tissues);

· intermediate lymph(passed through the lymph nodes);

· central lymph(located in the thoracic duct).

1. Homeostatic – maintaining the constancy of the cell microenvironment by regulating the volume and composition of the interstitial fluid.

2. Metabolic – participation in the regulation of metabolism through the transport of metabolites, proteins, enzymes, water, minerals, molecules of biologically active substances.

3. Trophic – transport nutrients(mainly lipids) from digestive tract into the blood.

4. Protective – participation in immune reactions (transport of antigens, antibodies, lymphocytes, macrophages and APCs).

Lymph consists of a liquid part ( plasma) And shaped elements. The closer lymphatic vessel to the thoracic duct, the higher the content of formed elements in its lymph. However, even in the central lymph, formed elements make up less than 1% of its volume.

Lymph plasma in concentration and composition of salts it is close to blood plasma, has an alkaline reaction (pH 8.4-9.2), contains less proteins and differs from blood plasma in their composition.

Formed elements of lymph.

The concentration of formed elements varies within the range of 2-20 thousand/μl (2-20´10 9 /l), changing significantly during the day or as a result of various influences.

Cellular composition of lymph: 90% lymphocytes, 5% monocytes, 2% eosinophils, 1% segmented neutrophils and 2% other cells. Red blood cells are normally absent from the lymph, entering it only when the permeability of the blood vessels of the microvasculature increases. Due to the presence of platelets, fibrinogen and other clotting factors, lymph is able to coagulate to form a clot.

1. Almazov V.A. Physiology of leukocytes. – L., Nauka, 1979.

2. Bykov V.L. Cytology and general histology (functional morphology of human cells and tissues). – St. Petersburg: SOTIS, 1998.

3. Vashkinel V.K., Petrov M.N. Ultrastructure and functions of human platelets. – L., Nauka, 1982.

4. Volkova O.V., Eletsky Yu.K. and others. Histology, cytology and embryology: Atlas: Textbook. – M.: Medicine, 1996.

5. Histology (introduction to pathology) / Ed. E.G. Ulumbekova, Yu.A. Chelysheva. – M.: GEOTAR, 1997.

7. Protsenko V.A., Shpak S.I., Dotsenko S.M. Tissue basophils and basophilic granulocytes of blood. – M., Medicine, 1987.

8. Reusch A. Fundamentals of immunology. Per. from English – M., Mir, 1991.

9. Sapin M.R., Etingen L.E. Human immune system. – M., Medicine, 1996.

10. Semchenko V.V., Samusev R.P., Moiseev M.V., Kolosova Z.L. International histological nomenclature. – Omsk: OGMA, 1999.

11. Willoughby M. Pediatric hematology. Per. from English – M., Medicine, 1981.

V. AGE FEATURES OF BLOOD……….………………23 – 24

Features of the leukocyte formula in childhood

Leukocyte formula is an indicator of the condition of peripheral blood, reflecting the percentage of leukocyte cells of different types. Normally, the ratio of cells of the lekopoietic series has characteristic features depending on the age of the child.

The situation with the formula in healthy children

In healthy newborns, a shift in the leukocyte formula is observed with a shift index of 0.2 (the norm in adults is 0.06). At the birth of a child, 60-65% of the leukogram is represented by neutrophils and 30-35% lymphocytes. By the end of the first week of life, the number of these cells is equalized

45% each and the “first crossover” of the leukocyte formula occurs and already by the day physiological lymphocytosis is formed in the newborn’s blood. The content of lymphocytes in the leukocyte formula is 55-60%. In addition, an increase in the number of monocytes up to 10% is typical. The second crossover in the leukocyte formula occurs at 5-6 years of age, after which by the age of 10 years the blood leukogram acquires the features of an adult:

band neutrophils – 1-6%,
segmented neutrophils 47-72%
lymphocytes 19-37%,
monocytes 6-8%,
eosinophils 0.5-5%,
basophils0-1%.

A sharp increase in the number of lymphocytes in the blood in the first week after birth and their predominance in the “white” blood formula until 5-6 years of age is a physiological compensatory mechanism associated with pronounced stimulation child's body antigens and formation immune system child. According to a number of authors, currently there is an earlier crossover in the leukocyte formula, a tendency to eosinophilia, relative neutropenia and an increase in the number of lymphocytes.

Changes in lymphocytes

When assessing the number of lymphocytes in a blood test in children, first of all, the age-related characteristics of the leukocyte formula are taken into account. Thus, in children under the age of 5-6 years, lymphocytosis is considered to be an increase in the relative number of lymphocytes over 60% and their absolute number over 5.5-6.0 x10 9 /l. In children over 6 years of age with lymphocytosis, the leukocyte blood count shows a lymphocyte content of more than 35%, and their absolute number exceeds 4 thousand. in 1 µl.

Functions of lymphocytes

The number of lymphocyte cells in the blood can be influenced by various physiological processes in the body. For example, a tendency to lymphocytosis is observed in children whose diet is dominated by carbohydrate foods, in residents of high mountains, and during menstruation in women. Children with constitutional abnormalities in the form of lymphatic diathesis also have a tendency to increase the content of lymphocytes in the blood.

The main function of lymphocytes is to participate in the formation of the immune response. Therefore, most often in pediatric practice There are secondary lymphocytic blood reactions that accompany:

viral infections (measles, influenza, rubella, adenovirus, acute viral hepatitis);
bacterial infections (tuberculosis, whooping cough, scarlet fever, syphilis)
endocrine diseases (hyperthyroidism, panhypopituitarism, Addison's disease, ovarian hypofunction, thymic hypoplasia);
allergic pathology ( bronchial asthma, serum sickness);
immunocomplex and inflammatory diseases(Crohn's disease, ulcerative colitis, vasculitis);
taking certain medications (analgesics, nicotinamide, haloperidol).

Lymphocytosis during viral infections is recorded, as a rule, in the convalescence stage - the so-called convalescent lymphocytosis.

A disease of viral etiology – infectious lymphocytosis – occurs exclusively among children (adults are extremely rarely affected). The disease has a flu-like benign course and may occur without clinical symptoms. In a blood test against the background of leukocytosis, the leukocyte formula of the blood demonstrates lymphocytosis.

Primary lymphocytosis in childhood is diagnosed with lymphoblastic leukemia.

Lifopenia

Lymphopenia is stated when the relative number of lymphocytes in children in the first days of life decreases - below 30%, in children under 5-6 years - below 50%, in children over 6 years - below 20%. A decrease in the number of lymphocytes occurs as a result of:

failure of the development of lymphoid tissue,
suppression of lymphocytopoiesis,
accelerated destruction of lymphocytes.

Relative lymphopenias are characteristic of infectious and inflammatory diseases accompanied by significant granulocytosis due to increased granulocytopoiesis. Absolute lymphocytopenia (the number of lymphocytes in children over 6 years of age is less than 1.2–1.5 × 109/l) indicates immunodeficiency. Observed in tuberculosis, syphiles. In patients with these infections, in most cases, an increase in lymphocytic agranulocytes is a favorable sign. Lymphopenic reaction accompanies AIDS, sarcoidosis, disseminated lupus erythematosus, lymphogranulomatosis. Drug-induced lymphocytopenia develops against the background of radiation and cytostatic therapy.

Monocyte change

Monocytes are the largest leukocyte cells blood, are representatives of the macrophage system of the body. The main function of monocytes is phagocytic. A leukocyte count of blood with a monocyte count of more than 10% indicates blood monocytosis (their absolute number is more than 0.4 × 109/l). Monocytosis has a diagnostic value:

during the period of convalescence after acute infections;
for granulomatosis (sarcoidosis, tuberculosis, ulcerative colitis, syphilis);
for protozoal, fungal and viral infections;
for collagenosis;
blood diseases (monoblastic leukemia).

It is worth mentioning a fairly common lymphotropic viral disease (caused by the herpes-like Epstein-Bar virus) in children (more often) - infectious mononucleosis. The main symptoms of the disease are fever, inflammatory changes in the pharynx, lymphadenopathy, enlarged spleen and liver, typical changes in blood tests in the form of an increased number of atypical mononuclear cells (over 10%) against the background of moderate leukocytosis and lymphocytosis.

A decrease in the number of monocytes in the blood count below 4% indicates monocytopenia. More often, this condition occurs with vitamin B12 folate deficiency anemia, aplastic anemia, leukemia, and can accompany systemic lupus erythematosus. In severe septic processes, the disappearance of monocytes is an unfavorable sign.

Changes in eosinophils

A leukocyte blood count recording eosinophilia is not uncommon in pediatric practice. Most often caused by allergies in children, which tends to increase nowadays, and helminthic infestations. An increase in the absolute number of eosinophilic granulocytes over 0.4x10 9 /l is considered eosinophilia. Eosinophils are normal in children, as well as in adults, making up 0.5-5% of total number leukocytes. An increase in the percentage from 5% to 15% is called “small” eosinophilia, over 15% is called “large”. In the latter case, the absolute content of eosinophilic cells in the peripheral blood can exceed 1.5? 10 9 /l. Eosinophilia against the background of significant leukocytosis is regarded as a leukemoid reaction of the eosinophilic type.

Eosinophilia can accompany systemic connective tissue diseases and arise as a result drug allergies. In some infectious conditions during the recovery period, the leukocyte blood count may register an increase in the number of eosinophils, the so-called “pink dawn of recovery” (when the smear is stained, eosinophils are pink).

An eosinophilic blood reaction may accompany oncological diseases, more often with the localization of the primary tumor process in the nasopharynx, bronchi, stomach, . May accompany various forms of leukemia, malignant neoplasms lymphoid tissue. A characteristic feature of tumor eosinophilia is the absence of an increase in the concentration of JgE in the blood serum.

Familial benign eosinophilias have been described, occurring asymptomatically and inherited in an autosomal dominant manner.

Change in the number of basophils

Basophilic granulocytes participate in the formation of the immune (usually allergic) and inflammatory response in the human body. With basophilia, the leukocyte blood count shows a content of basophilic cells over 0.5-1%. Basophilia is a rare phenomenon. An increase in basophilic cells to 2-3% more often occurs in chronic myeloid leukemia, lymphogranulomatosis, hemophilia, tuberculosis of the lymph nodes, and allergic reactions.

Conclusion

The tactics of a practicing physician for various cellular blood reactions in children primarily depend on clinical picture diseases. If changes in the blood are a symptom of a disease, then, first of all, it is treated. If, after the patient’s clinical recovery, blood tests still show pathological changes, then additional diagnostic measures for the purpose of diagnosing complications or concomitant diseases. In some cases, it may be necessary to consult a pediatric hematologist or oncologist.

Leukocyte formula in children. Norm, transcript. Cross, what is this?

A general blood test in children, and in particular the leukocyte formula, differs from that in an adult. What are the norms and features of the formula for children? What is cross blood formula?

The leukocyte formula is the percentage of all types of leukocytes (granulocytes: neutrophils, including rod and segmented ones, eosinophils, basophils, agranulocytes: monocytes and lymphocytes). Those. In a stained blood smear, 100 leukocytes in a row within the field of view are counted and the percentage of each type is calculated.

Newborns.

At birth, children have leukocytosis up to (10 to 9 per liter). Of these, neutrophils are predominant (60-70%). In this case, there is a shift of the formula to the left, i.e. the number of rods is increased to 10-15%, sometimes there are single metamyelocytes. Lymphocytes are about 30%. Eat conditional rule: neutrophils + lymphocytes equal about 90%. The remaining types of leukocytes are the same as in adults (basophils 0-1%, eosinophils 0.5-5%, monocytes 3-10%).

First 5 days of life.

On average, on day 5 the first crossover of the formula occurs, i.e. the number of neutrophils and lymphocytes levels out, becoming an average of 45%.

From 10 days to 4-5 years.

Lymphocytes about 60%, neutrophils - 30%

4-5 years.

On average, at 4.5-5 years the second crossover of the formula occurs, i.e. again the number of neutrophils and lymphocytes is equal to 45%.

School age.

By school age, the leukocyte formula in children corresponds to that of adults.

The lymphocyte formula - the ratio of leukocytes (band, segmented, eosinophils, lymphocytes, basophils and monocytes) in a stained blood smear - in children differs from that in adults until about 4-5 years. In newborns, up to a week of age, it is approximately the same as in adults, and then the first cross occurs. The leukocyte formula changes: the ratio of lymphocytes to neutrophils changes from approximately 20%/60% to 60%/20%. At 4-5 years go by reverse cross and does not change.

Cross leukocyte formula

Leukocyte formula crossover, blood formula crossover... This definition can be heard quite often if we're talking about about blood tests in children. What can “cross” the results of the study, how do laboratory technicians determine this, and what does this even mean?

What is the leukocyte formula:

As everyone knows, blood contains three types of blood cells: red (erythrocytes), white (leukocytes) and platelets. When a person gets a blood test, the technician writes the absolute number of each of these groups of cells on the results. For example, on average there are 4-5 × 1012 red blood cells per 1 liter of blood, 3-9 × 109 leukocytes per the same volume.

Among leukocytes there are several forms. More precisely, there are several dozen of them, since each form includes a number of other types of cells of an intermediate degree of maturity. However, there are not many main types of leukocytes. These are neutrophils, lymphocytes, monocytes, eosinophils, basophils.

Neutrophil (purple, right) and

lymphocyte (purple, left) –

main participants of the crossover

Instead of counting the exact number of cells of a given shape, the researchers report their content as a percentage. For example, neutrophils can be 45-70%, lymphocytes - 20-40%, monocytes 6-8%, basophils 0-1%, eosinophils 1-3% of all leukocytes. The total is 100%.

The number of leukocytes and their varieties is the leukocyte formula. In an adult, it is relatively stable and changes only during diseases, when the content of different cells changes. However, in young children, quite large changes occur in it, which are called the crossover of the formula. The crossover is observed normally and is not a sign of pathology.

Segmented neutrophils, lymphocytes: how do they change during crossover?

The crossover of the formula occurs due to the fact that small child formation and maturation of immunity occurs. Different shapes cells are formed in larger or smaller quantities, all this changes over time... This is where the natural changes in blood tests come from.

At approximately 10 years of age, the leukocyte formula stops changing, and all values approach the norms that were described at the beginning of the article.

Biological role of the cross:

For a person who does not plan to connect his life with medicine, it is quite boring to understand which indicator is increased and which is decreased and when. If this is of interest to you, you can study and memorize the contents of the previous section in detail. However, if we are talking about your child's blood tests, and you just want to know if everything is in order, it is better to entrust their interpretation to a knowledgeable specialist who has been dealing with this for a long time. You just need to understand a few simple things.

The main thing that is needed while a child is growing is, if possible, to ensure that he grows up without stress: chronic and acute diseases, sudden climate change, long journeys, etc. In addition, immune support with which childhood will pass without lingering colds and frequent illness.

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24. Age-related features in the number of leukocytes. Double crossover in the ratio of neutrophils and lymphocytes in children.

The number of leukocytes in newborns is increased and equal to *10 9 /l. The number of neutrophils is -60.5%, eosinophils - 2%, basophils -02%, monocytes -1.8%, lymphocytes - 24%. During the first 2 weeks, the number of leukocytes decreases to 9 - 15 * 10 9 / l, by 4 years it decreases to 7-13 * 10 9 / l, and by 14 years it reaches the level characteristic of an adult. The ratio of neutrophils and lymphocytes changes, which causes the occurrence of physiological crossovers.

First cross. In a newborn, the ratio of the content of these cells is the same as in an adult. Subsequently sod. Nf falls, and Lmf increases, so that by 3-4 days their number is equalized. Subsequently, the amount of Nf continues to decrease and by 1-2 years reaches 25%. At the same age, the amount of LMF is 65%.

Second cross. Over the next years, the number of Nf gradually increases, and Lmf decreases, so that in children of 4 years these figures are equalized again and constitute 35% of the total number of leukocytes. The number of Nf continues to increase, and the number of Lmf decreases, and by the age of 14 these indicators correspond to those of an adult (4-9 * 10 9 / l).

25. Genesis, structure, general and special. Properties and functions of neutophils

In the bone marrow, six successive morphological stages of neutrophil maturation can be observed: myeloblast, promyelocyte, myelocyte, metamyelocyte, band and segmented cell:

In addition, there are also earlier, morphologically unidentifiable, committed neutrophil precursors: CFU-GM and CFU-G.

Neutrophil maturation is accompanied by a progressive decrease in nuclear size due to chromatin condensation and loss of nucleoli. As the neutrophil matures, the nucleus becomes jagged and finally acquires its characteristic segmentation. At the same time, changes occur in the neutrophil cytoplasm, where granules containing biological compounds accumulate, which will subsequently play such a role. important role in protecting the body. Primary (azurophilic) granules - inclusions blue approximately 0.3 µm in size, containing elastase and myeloperoxidase. They first appear at the promyelocytic stage; When ripe, their number and intensity of coloring decrease. Secondary (specific) granules, which contain lysozyme and other proteases, appear at the myelocyte stage. The coloring of these secondary granules gives rise to the characteristic neutrophilic appearance of the cytoplasm.

Kinetics of neutrophils. According to their ability to divide, myeloblasts, promyelocytes and myelocytes belong to the mitotic group, i.e. have the ability to divide, the intensity of which decreases from myeloblast to myelocyte. Subsequent stages of neutrophil maturation are not associated with division. In the bone marrow, proliferating cells among neutrophils account for about 1/3, and the same amount accounts for granulocytic mitoses among all proliferating cells in the bone marrow. During the day, up to 4.0 × 10 9 neutrophils per kilogram of body weight are produced.

Structure. Neutrophil cytoplasm. At the metamyelocyte stage and subsequent stages of maturation, the structures that ensure the synthesis of cytoplasmic proteins are reduced, the structure of lysosomes that provide the function of neutrophils is improved, and the ability for amoeboid motility and deformation that ensures the mobility and invasiveness of granulocytes is enhanced.

Neutrophil membrane. CD34+CD33+, as well as receptors for G M - C S F, G - C S F, IL-1, IL-3, IL-6, IL-11, IL-12, are determined on the precursors of the granulocyte lineage. The membrane also contains various molecules that are receptors for chemotactic signals, which include CCF, N-formyl peptide.

Properties and functions. The function of neutrophils is to protect the body from infection. This process includes chemotaxis, phagocytosis and destruction of microorganisms. Chemotaxis involves the ability to detect and target movement towards microorganisms and foci of inflammation. Neutrophils have specific receptors for the C5a component of the complement system (produced in classical or alternative ways complement activation) and proteases released during tissue damage or direct bacterial exposure. In addition, neutrophils have receptors for N-formyl peptides released by bacteria and damaged mitochondria. They also react to such inflammatory products as leukotriene LTB-4 and fibrinopeptides.

Neutrophils recognize foreign organisms using opsonin receptors. Fixation of serum IgG and complement on bacteria makes them recognizable to granulocytes. The neutrophil has receptors for the Fc fragment of the immunoglobulin molecule and the products of the complement cascade. These receptors initiate the processes of capture, absorption and adhesion of foreign objects.

Neutrophils engulf opsonized microorganisms using cytoplasmic vesicles, called phagosomes. These vesicles advance from the folded pseudopodia and fuse with primary and secondary granules through an energy-dependent process during which glycolysis and glycogenolysis occur in phagocytes. During cell degranulation, the contents of the granules are released into the phagosome and degradation enzymes are released: lysozyme, acidic and alkaline phosphatase, elastaseylactoferrin.

Finally, neutrophils destroy bacteria by metabolizing oxygen to produce products that are toxic to the ingested microorganisms. The oxidase complex that generates these products consists of flavin- and heme-containing cytochrome b558-.

These reactions use the reducing agent NADPH and are stimulated by glucose-6-phosphate dehydrogenase and other hexose monophosphate shunt enzymes. As a result, the cell generates superoxide (O2) and hydrogen peroxide (H2O2), which are released into the phagosome to kill bacteria. Lactoferrin is involved in the formation of free hydroxyl radicals■, and myeloperoxidase, using halogens as cofactors, in the production of hypochlorous acid (HOC1) and toxic chloramines.

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Leukocyte formula crossover, blood formula crossover... This definition can be heard quite often when it comes to blood tests in children. What can “cross” the results of the study, how do laboratory technicians determine this, and what does this even mean?

What is the leukocyte formula:

Neutrophil (purple, right) and
lymphocyte (purple, left) -
main participants of the crossover

The number of leukocytes and their varieties is the leukocyte formula. In an adult, it is relatively stable and changes only during diseases, when the content of different cells changes. However, in young children, quite large changes occur in it, which are called the crossover of the formula. The crossover is observed normally and is not a sign of pathology.

Segmented neutrophils, lymphocytes: how do they change during crossover?

The crossover of the formula occurs due to the fact that in a small child the formation and maturation of immunity occurs. Different forms of cells are formed in greater or lesser quantities, all this changes over time... This is where the natural changes in blood tests come from.

Now about why this phenomenon is called crossover. The thing is that with it, the indicators of neutrophils and lymphocytes “cross” each other. First, neutrophils (segmented) are decreased, neutrophils are increased. Then everything changes: segmented neutrophils are increased, lymphocytes are decreased. In more detail, this happens as follows...

A newly born child has “normal” lymphocytes and neutrophils, there is no increase or decrease, and the indicators of these cells resemble those of adults: the first 30-35%, the second 60-65%.

However, by the age of one week, changes occur: the indicators “approach” each other. As a result, it turns out that segmented cells are decreased and lymphocytes are increased relative to the values that the little man had quite recently. Both parameters “occur” at a value of 45% - by the age of 4-7 days in the child’s blood they become equal.

Then each of them continues to change in the same direction, but at a different “speed”. By 10-14 days, a person has rather low segmented neutrophils, while lymphocytes increase and reach a content of 55-60%. In addition, at the same time, the level of monocytes in the blood increases slightly, up to 10%.

The subsequent months and years do not bring such dramatic changes in the composition of the blood as the first days of life. However, gradually segmented neutrophils increase, and lymphocytes decrease again. At 5-6 years old, their number becomes equal again. This is the second and last crossover of the leukocyte formula. Then some more changes occur, and everything turns out in such a way that, as a result, neutrophils are increased, and lymphocytes are decreased relative to that “average” 45%.

At approximately 10 years of age, the leukocyte formula stops changing, and all values approach the norms that were described at the beginning of the article.

Biological role of the cross:

For a person who does not plan to connect his life with medicine, it is quite boring to understand which indicator is increased and which is decreased and when. If this is of interest to you, you can study in detail and remember the contents of the previous section. However, if we are talking about your child's blood tests, and you just want to know if everything is in order, it is better to entrust their interpretation to a knowledgeable specialist who has been dealing with this for a long time. You just need to understand a few simple things.

Crossing the formula is a normal, physiological phenomenon. The immunity of a child who has recently been born experiences a big shake-up, as it immediately begins to be affected by large number irritants. Gradually, all these processes “settle down”, and the immune system comes to a stable state.

The main thing that is needed while the child is growing is, if possible,
ensure that he grows up without stress: chronic and acute diseases, sudden climate change, long journeys, etc. In addition, immune support would be very useful, with which childhood will pass without lingering colds and frequent illness.

Reception Transfer Factor drug, created on the basis of information molecules, can help with this. These molecules teach lymphocytes to work properly, which allows the child’s immune system to mature faster and acquire high resistance to all possible diseases, creating the key to good health for the future.

What is cross blood formula?

Newborns.

At birth, children have leukocytosis up to (10 to 9 per liter). Of these, neutrophils are predominant (60-70%). In this case, there is a shift of the formula to the left, i.e. the number of rods is increased to 10-15%, sometimes there are single metamyelocytes. Lymphocytes are about 30%. There is a conditional rule: neutrophils + lymphocytes are equal to about 90%. The remaining types of leukocytes are the same as in adults (basophils 0-1%, eosinophils 0.5-5%, monocytes 3-10%).

First 5 days of life.

On average, on day 5 the first crossover of the formula occurs, i.e. the number of neutrophils and lymphocytes levels out, becoming an average of 45%.

From 10 days to 4-5 years.

Lymphocytes about 60%, neutrophils - 30%

4-5 years.

On average, at 4.5-5 years the second crossover of the formula occurs, i.e. again the number of neutrophils and lymphocytes is equal to 45%.

School age.

By school age, the leukocyte formula in children corresponds to that of adults.

Leukocyte formula in children

The leukocyte formula in children has significant differences depending on age. The leukocyte formula of a newborn (with the exception of the first days of life, when neutrophilia is noted) is characterized by persistent lymphocytosis, both relative and absolute (Table 2). In a newborn, the percentage of lymphocytes, gradually increasing, reaches 50-60 by the 5th day, and the percentage of neutrophils by the same time gradually decreases to 35-47.

The number of neutrophils and lymphocytes in different periods of childhood (in percentage): a - first crossover; b - second cross.

If we depict changes in the number of neutrophils and lymphocytes in the form of curves (Fig.), then approximately between the 3-5th day there is an intersection of the curves - the so-called first crossover. By the end of the first month of life, the child’s leukocyte formula is established, characteristic of the entire first year of life. The leukocyte formula of infants is somewhat unstable; it is relatively easily disrupted by severe crying and restlessness of the child, sudden changes in diet, cooling and overheating, and especially by various diseases.

Table 2. Leukocyte formula of a newborn (according to A.F. Tour, in%)

By the end of the first month of life, the child has established a leukocyte formula characteristic of the first year of life (Table 3). It is dominated by lymphocytes; There is always a moderate shift of neutrophils to the left, moderate monocytosis and an almost constant presence of plasma cells in the peripheral blood. The percentages between individual forms of white blood cells in infants can vary within very wide limits.

Leukocyte formula of children aged 1 month to 15 years (according to A.F. Tour, in%)

Correct assessment of the leukocyte formula in diseases is of great importance and is possible by taking into account its characteristics, determined by the age of the child.

24. Age-related features in the number of leukocytes. Double crossover in the ratio of neutrophils and lymphocytes in children.

25. Genesis, structure, general and special. Properties and functions of neutophils

In the bone marrow, six successive morphological stages of neutrophil maturation can be observed: myeloblast, promyelocyte, myelocyte, metamyelocyte, band and segmented cell:

In addition, there are also earlier, morphologically unidentifiable, committed neutrophil precursors: CFU-GM and CFU-G.

Neutrophil maturation is accompanied by a progressive decrease in nuclear size due to chromatin condensation and loss of nucleoli. As the neutrophil matures, the nucleus becomes jagged and finally acquires its characteristic segmentation. At the same time, changes occur in the neutrophil cytoplasm, where granules containing biological compounds accumulate, which will subsequently play such an important role in protecting the body. Primary (azurophilic) granules are blue inclusions approximately 0.3 µm in size, containing elastase and myeloperoxidase. They first appear at the promyelocytic stage; When ripe, their number and intensity of coloring decrease. Secondary (specific) granules, which contain lysozyme and other proteases, appear at the myelocyte stage. The coloring of these secondary granules gives rise to the characteristic neutrophilic appearance of the cytoplasm.

Properties and functions. The function of neutrophils is to protect the body from infection. This process includes chemotaxis, phagocytosis and destruction of microorganisms. Chemotaxis involves the ability to detect and target movement towards microorganisms and foci of inflammation. Neutrophils have specific receptors for the C5a component of the complement system (produced in the classical or alternative pathways of complement activation) and proteases released during tissue damage or direct bacterial exposure. In addition, neutrophils have receptors for N-formyl peptides released by bacteria and damaged mitochondria. They also react to such inflammatory products as leukotriene LTB-4 and fibrinopeptides.

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LEUKOCYTE CROSSING

(RULE OF FOUR FOURS)

65% lymphocyte blood profile

4 days 1 year 4 years age

Figure 12. Leukocyte crossover.

In a newborn, the percentage of neutrophils and lymphocytes is the same as in an adult. Subsequently, the content of neutrophils decreases, and the content of lymphocytes increases, so that by 3-4 days their number is equalized (44%). This phenomenon is called first physiological (leukocyte) crossover. Subsequently, the number of neutrophils continues to decrease and by 1-2 years reaches 25%. At the same age, the number of lymphocytes is 65%, that is, at this age a lymphocytic blood profile is observed. Over the following years, the number of neutrophils gradually increases, and the number of lymphocytes decreases, so that in 4-year-old children these indicators are equalized again (44%) - second physiological (leukocyte) crossover. The number of neutrophils continues to increase, and the number of lymphocytes continues to decrease, and by the age of 14 these indicators correspond to those of an adult, that is, a neutrophilic blood profile is observed.

Lymph(from the Greek lympha - pure moisture, spring water) - biological fluid formed from interstitial (tissue) fluid, passing through the system of lymphatic vessels through a chain of lymph nodes (in which it is cleansed and enriched with formed elements) and through the thoracic duct into the blood.

Mechanism of lymph formation associated with the filtration of plasma from the blood capillaries into the interstitial space, resulting in the formation of interstitial (tissue) fluid. In a young man weighing 70 kg, the interstitial space contains about 10.5 liters of fluid. This fluid is partially reabsorbed into the blood and partially enters the lymphatic capillaries, forming lymph. The formation of lymph is facilitated by increased hydrostatic pressure in the interstitial space and differences in oncotic pressure between blood vessels and interstitial fluid (ensuring the daily flow of proteins from the blood into the tissue fluid). These proteins are completely returned to the blood through the lymphatic system.

Lymph volume in the human body is, on average, 1-2 liters.

· peripheral lymph(flowing from tissues);

· intermediate lymph(passed through the lymph nodes);

· central lymph(located in the thoracic duct).

1. Homeostatic – maintaining the constancy of the cell microenvironment by regulating the volume and composition of the interstitial fluid.

2. Metabolic – participation in the regulation of metabolism through the transport of metabolites, proteins, enzymes, water, minerals, molecules of biologically active substances.

3. Trophic – transport of nutrients (mainly lipids) from the digestive tract into the blood.

4. Protective – participation in immune reactions (transport of antigens, antibodies, lymphocytes, macrophages and APCs).

Lymph consists of a liquid part ( plasma) And shaped elements. The closer the lymphatic vessel is to the thoracic duct, the higher the content of formed elements in its lymph. However, even in the central lymph, formed elements make up less than 1% of its volume.