Physiological leukocytosis it is determined by the rule of increasing the percentage of neutrophils in relation to the other elements and is found in the following situations:
- For newborns and children
- Postprandial
- Climatic and seasonal variations – heat and intense solar radiation, artificial and ultraviolet light can favor the transient growth of leukocytes
- During pregnancy, during labor, during lactation, during menstruation
- In conditions of intense physical effort, emotions, fear and pain.
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Pathological leukocytosis can be associated with a wide range of pathologies, the most frequently encountered conditions in current medical practice that cause an increase in the number of white cells including:
- Acute bacterial infections – in adults, acute bacterial infections cause neutrophilia. In children, leukocytosis persists even in chronic forms of bacterial infections. Learn more about the difference between viral and bacterial infections
- Metabolic disorders – gout, uremia, metabolic acidosis
- bleeding acute or intravascular hemolysis
- Drug poisoning or heavy metals
- Extensive lesions – burns, destruction or muscle tears (crushing syndrome)
- Pulmonary or heart attack
- Hemato-oncological pathologies – leukemias, polycythemia vera, myeloproliferative diseases
- bleeding in closed cavities – perforated ulcer, ruptured ectopic pregnancy
- Certain non-hematological oncological pathologies especially bronchial carcinoma.
In the presence of specific clinical manifestations of these pathologies, the attending physician may recommend performing a blood count with leukocyte formula in order to confirm the suspected diagnosis.
What are leukocytes?
Leukocytes or white cells represent mobile and circulating cellular elements that have the ability to recognize and destroy pathogens that have entered the body through specific mechanisms.
Leukocytes are nucleated cells of various sizes with or without granules in the cytoplasm that are divided into granulocytes and agranulocytes. Granulocytes in turn are divided into:
- neutrophil
- Eosinophils
- Basophils are also called polymorphonuclear due to the polylobate nucleus (consisting of several lobes).
Non-granulocytes represented by lymphocytes and monocytes as a rule, they contain distinct cytoplasmic granules and have a non-lobulated nucleus, being also called mononuclear leukocytes.
The role of leukocytes in the functioning of the body
Neutrophils, lymphocytes, monocytes, eosinophils and basophils represent cells with individualized functions involved in the body’s immune defense mechanisms by fulfilling the following roles:
- Lymphocytes ensure humoral immunity through the synthesis of IgA, IgG, IgD, IgE and IgM antibodies with the aim of a destroys viral and bacterial pathogens that come into contact with the body.
- For neutrophils they are able to recognize and specifically bind certain bacterial pathogens, for their phagocytic and removal from the body.
- Basophils are involved in allergic reactions, being able to produce histamine and heparin with the initiation of the inflammatory response and the prevention of hypercoagulability of the blood.
- eosinophils they are involved together with basophils in allergic reactions and additionally, present destruction activity of parasitic pathogens and neoplastic cells.
- Monocytes has the ability to phagocytize necrotic residues and microorganisms” „non self” from the circulatory level. Monocytes have an immunostimulating role due to their ability to produce interferon.
Learn more about how the immune system works.
Leukocytosis in chronic conditions
The main chronic diseases that evolve with persistent leukocytosis include:
- Allergies
- Autoimmune diseases
- Vasculitis
- Tumor processes
- Chronic infections
- Asplenia
- Certain genetic syndromes
- Connective tissue diseases.
Leukocytosis in acute conditions
In most situations, leukocytosis is due to a acute inflammatory or infectious pathologies of viral or bacterial causebut the transient increase in leukocytes can also be due to extensive trauma caused by crushing or an acute myocardial infarction.
In the absence of a myeloproliferative disease, transient leukemic reactions with values of neutrophils over 50,000/mmc can occur in the context of a acute bacterial infections, sepsis or graft-versus-host disease.
Flu and viruses respiratory causes leukocytosis in the early stages of development, and in the case of children it usually associates the increase of lymphocytes.
In most situations, however, infections due to influenza viruses A, B and C and common respiratory viruses evolve with leukopenia or a normal leukocyte formula. Leukocytosis that manifests against the background of a flu or respiratory virus signals the emergence of a bacterial superinfection and associates neutrophilia, along with specific clinical manifestations of the patient that support the complicated evolution of the pathology.
Normal leukocyte values
The normal values of leukocytes vary by age group, being included in the following biological reference intervals:
Age
leukocyte x103/ µL
< 1 luna- 1 luna
5-20
2 months-1 year
6-17.5
2-3 years
6-17
4-5 years
5.5-15.5
6-8 years
5-14.5
9-14 years
4.5-13.5
15-17 years
4.5-13
18-74 years
4-10
During pregnancy, a mild leukocytosis can be observed with an increase in the number of neutrophils near birth, the normalization of values occurring 4-5 days after birth. A leukocyte value between 5.8-13.2 x103/ µL is considered to be normal in the last trimester of pregnancy, without signaling the presence of an infection of the maternal body.
Leukocytes in the urine
The presence of leukocytes in the urine is confirmed by the esterase reaction with the help of special strips or by microscopic examination of the urinary sediment. Biochemical tests that use leukocyte esterase can detect both intact and lysed leukocytes, but the results obtained are qualitative (it cannot be used to measure the amount of leukocytes).
Leukocyturia (presence of leukocytes in the urine) is suggestive of inflammatory diseases of the urinary tract which include:
- Bacterial infections with uropathogenic germs (cystitis, urethritis, acute or chronic pyelonephritis)
- Fungal and parasitic infections (schistosomiasis)
- glomerulopathy
- Intoxications and urinary obstructions.
Abacterial leukocyturia refers to situations in which the leukocyte esterase test is positive in the absence of leukocytes in the urine and is more often found in tuberculosis and tumoral diseases of the urinary tract.
Leukocytes and adaptive immunity
Adaptive immunity acts as a secondary line of defense and offers protection in case of re-exposure of the body to a previously encountered pathogen. This type of immunity is slower and responds specifically by generating an immunological memory by activating T helper lymphocytes (TH and CD4) that coordinate a particular immune response to the presented antigen.
CD4 T lymphocytes secrete cytokines and modulate the activity of B and cytotoxic T lymphocytes that ensure humoral and cell-mediated immunity. Later, when the T cell encounters the same bacterial pathogen again, it immediately recognizes it and triggers a prompt immune response to it faster than in the case of the first contact.
The leukocyte values are interpreted by the doctor who recommended the blood count in the clinical context of the patient, being always correlated with the manifestations and personal antecedents of the patient in question. The increase in the number of leukocytes is not specific for a certain pathology and in most cases the attending physician requests other investigations to establish the diagnosis.
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2024-01-31 23:03:19
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