Neutrophils

Neutrophil granulocytes are characterized by the presence in the cytoplasm of granules of two types: azurophilic and specific, the contents of which allow these cells to perform their functions. The azurophilic granules appearing at the stage of myeloblast contain myeloperoxidase, neutral and acid hydrolases, cationic proteins, lysozyme. Specific granules appearing on the myelocyte stage contain lysozyme, lactoferrin, collagenase, aminopeptidase. Approximately 60% of the total number of granulocytes is in the bone marrow, forming a bone marrow reserve, 40% in other tissues, and only less than 1% in the peripheral blood. Normally, segmented neutrophils and a relatively small number of stab neutrophils( 1-5%) are present in the blood. The main function of neutrophils is to protect the body from infections, which is mainly carried out with the help of phagocytosis. The duration of the half-cycle of circulation of neutrophilic granulocytes in the blood is 6.5 h, then they migrate into the tissue. The lifetime of granulocytes in tissues depends on many causes and can range from a few minutes to several days. The reference values ​​of the neutrophil count in the blood are given in Table.[Titz N., 1997].

For leukocytosis( leukopenia), an uncharacteristically proportional increase( decrease) in the number of leukocytes of all species;in most cases, they show an increase( decrease) in the amount of any one type of cells, so the terms "neutrophilia," "neutropenia," "lymphocytosis," "lymphopenia," "eosinophilia," "eosinopenia," etc. are used.

Table Reference values ​​for the absolute and relative content of neutrophils in the blood

Table Reference values ​​for absolute and relative neutrophil count in the blood

Neutrophilia( neutrophilia) - an increase in the neutrophil count above 8x109 / l. Sometimes the leukocyte reaction can be expressed very sharply and is accompanied by the appearance in the blood of young elements of hemopoiesis up to the myeloblasts. In such cases it is customary to speak of a leukemo-id reaction. Leukemoid reactions are changes in the blood of a reactive nature, reminiscent of leukemia by the degree of increase in the content of leukocytes( above 50x109 / l) or by the morphology of cells. High neutrophilic leukocytosis( up to 50x109 / L) with rejuvenation of the leukocyte composition( shift to the left of different degrees up to promyelocytes and myeloblasts) can occur with acute bacterial pneumonia( especially croupous) and other severe infections, acute hemolysis. Leukemoid reactions of neutrophil type( with or without leukocytosis) are possible in malignant tumors( cancer of the kidney parenchyma, milk and prostate gland), especially with multiple metastases to the bone marrow. Differential diagnostics with blood diseases are performed based on the data of a red bone marrow biopsy, studies of alkaline phosphatase in leukocytes( in leukemia reactions it is high, with chronic myeloid leukemia - low), hemogram dynamics.

Neutrophilosis is one of the main objective diagnostic criteria for any suppuration, especially sepsis. It was found that the higher the leukocytosis, the more pronounced the positive reaction of the organism to infection. The number of leukocytes in the peripheral blood, especially with staphylococcal sepsis, can reach 60-70x109 / l. Sometimes the dynamics of the leukocyte reaction has a wavy character. Sepsis, caused by gram-negative flora, usually occurs with less pronounced leukocyte reaction. With gram-negative sepsis, the increase in leukocytes to 18x109 / L significantly worsens the prognosis of the disease. Along with the increase in the number of leukocytes in sepsis, it is possible to reduce them to 3-4x109 / l, which is more often observed with gram-negative sepsis. The most significant suppression of the leukocyte reaction is noted with septic shock( 2x109 / L).For severe forms of Pseudomonas septicemia with the development of septic shock is characterized by the development of severe leukopenia, reaching 1.6 × 109 / l. In patients with renal insufficiency, neutropenia is also often observed right up to agranulocytosis.

Neutropenia - the neutrophil count in the blood is lower than 1,5х109 / l. The main etiological factors causing neutropenia are listed in Table. However, when analyzing the causes of neutropenia, one should also remember about rare diseases accompanied by a decrease in the number of neutrophils in the blood, some of which are presented below.

■ Costmann's neutropenia is an autosomal recessive hereditary disease caused by a defect in the colony-stimulating factor receptor. It is characterized by severe neutropenia( neutrophils or none at all, or their content does not exceed 1-2%) and is accompanied by various infections, first by abscesses on the body - furuncles and carbuncles, then - by repeated pneumonia, lung abscesses. Symptoms of the disease appear on the 1-3 th week after birth, if the children do not die at the age of 1, then the severity of the infectious processes decreases somewhat

, the relative compensation of the disease occurs. The total number of leukocytes in the blood is usually within the norm( due to an increase in the number of monocytes and eosinophils), neutropenia is very deep, the neutrophil count is less than 0.5x109 / l.

■ Benign hereditary neutropenia is a familial disease that is not often clinically manifested. In most patients, the total number of leukocytes is normal, neutropenia is moderate( up to 2030%), other blood counts are normal.

■ Cyclic neutropenia is a disease characterized by a periodic( usually a fairly accurate interval - from 2-3 weeks to 2-3 months, for each individual patient) by the disappearance of neutrophils from the blood. Before the occurrence of an "attack" the patient's blood has a normal composition, and with the disappearance of neutrophils, the content of monocytes and eosinophils increases.

The main causes of neutrophilia and neutropenia are presented in the table.

Table Diseases and conditions accompanied by changes in the number of neutrophils in the blood

Table Diseases and conditions accompanied by changes in the number of neutrophils in the blood

Agranulocytosis is a sharp decrease in the number of granulocytes in the peripheral blood until they disappear completely, leading to a decrease in the body's resistance to infections and the development of bacterial complications. Depending on the mechanism of origin, distinguish between myelotoxic and immune agranulocytosis. Myelotoxic agranulocytosis occurs as a result of the action of cytostatic factors. He is characterized by a combination of leukopenia with thrombocytopenia and often with anemia( that is, pancytopenia).Immune agranulocytosis is mainly of two types: haptenic and autoimmune, and also isoimmune.