White blood cells or leukocytes are blood cells responsible for defending the body. They have normal values and morphological characteristics that identify them. Therefore, any alteration may indicate the presence of a pathology.
White blood cells or leukocytes are cells involved in defending the body against harmful agents and can have their own disorders. Within the functions of this group of cells is the mediation of inflammatory processes, whose main purpose is the neutralization of any noxa.
There are 5 types of leukocytes in the bloodstream, which are classified according to the presence or absence of granules in their cytoplasm. Those that do have granules are known as granulocytes (neutrophils, eosinophils, and basophils). These names are the result of the color they acquire with the stain. In contrast, leukocytes that do not have visible granules under an optical microscope are monocytes and lymphocytes.
Each type of white blood cell has its own functions, being essential for the immune system. Due to this, the determination of leukocytes in a blood sample is very useful.
Leukocytosis: Elevated White Blood Cell Disorders
Leukocytes have normal values that are within a range. In general terms, these figures fluctuate between 5,000 and 11,000 cells per microliter.
Any deviation in the white blood cell count may indicate the presence of an abnormality. When this value is above the upper limit, it is called leukocytosis.
Since each cell type has specific functions, the total white blood cell count may not provide much information. For this reason, the clinical laboratory also determines the leukocyte formula, in which the percentage represented by each cell line in the sample is reported.
The elevation of the neutrophil value above 7500 cells per milliliter is called neutrophilia. There are circumstances in which these leukocytes appear increased without signifying an underlying alteration; such is the case of the neonatal period and the last trimester of pregnancy.
However, these values are also established and must always be correlated with the clinical status of the patient.
The most frequent causes of neutrophilia are bacterial infections, but these white blood cells can be elevated in inflammatory processes, smoking and physical or emotional stress. Similarly, immature cells may be reported in the differential; especially, the presence of arches or band cells. This particularity is called deviation to the left.
Other less common causes of neutrophilia include the following
- Use of drugs: adrenaline, glucocorticoids, heparin, lithium.
- Metabolic disorders: gout, acidosis, hyperthyroidism.
- Tissue necrosis: myocardial infarction, burns, gangrene.
- Autoimmune diseases.
- Down’s Syndrome.
The symptoms presented by the patient depend on the underlying cause, since there is no direct relationship between neutrophilia and the appearance of specific clinical manifestations.
The presence of an elevated lymphocyte count is called lymphocytosis. The main cause of this alteration of white blood cells is viral infection
However, it is possible to show lymphocytosis in processes of bacterial origin, such as whooping cough, brucellosis and syphilis. Similarly, tuberculosis and toxoplasmosis can lead to an increased lymphocyte count.
However, chronic lymphocytosis should be a cause for specialized study, especially when there is clinical suspicion of a lymphoproliferative process. It is important to look for lymphadenopathy on physical examination. Likewise, the morphological analysis through a peripheral blood smear must be in the hands of an expert hematologist.
An extreme leukocytosis with a white blood cell count above 50,000 cells per milliliter constitutes the leukemoid reaction. This entity can resemble some forms of leukemia.
Therefore, it is important to know its existence and make an opportune differential diagnosis. It is caused by serious bacterial infections and tissue necrosis. The presence of immature cells is usual.
Other disorders with increased white blood cells
There may be a slight increase in leukocytes, due to cells that represent a small percentage of the leukocyte formula. For this reason, they often go unnoticed and are often underestimated. Still, they are of clinical importance, as they may indicate an underlying condition.
When eosinophils are increased, we speak of eosinophilia. Allergic reactions, bronchial asthma and parasitic infections are usually the most frequent causes of this leukogram alteration.
In general, the symptoms will depend on the underlying condition. Therefore, they will regress when treating said condition. However, there are myeloid and lymphoid neoplasms that present with chronic eosinophilia.
A rare abnormality of white blood cells is basophilia. The increase in basophils may be due to hypersensitivity reactions and both infectious and inflammatory processes.
It is important to note that when basophilia is intense, symptoms related to the release of histamine appear, which is the molecule contained in the granules of these cells. Therefore, physical manifestations may include the following:
- Arterial hypotension.
However, the presence of persistent basophilia should lead to suspicion of a lymphoproliferative process and it is important to refer the patient to a specialist so that it can be studied appropriately and early.
Monocytes may also appear increased on the blood count. This increase is often due to chronic inflammatory processes:
- Rheumatoid arthritis.
- Systemic lupus erythematosus.
- Crohn’s disease.
- Ulcerative colitis.
Likewise, monocytosis can evidence an intracellular infection, such as malaria and leishmaniasis. Hematic neoplasms can also present with elevated monocytes.
Leukopenia: disorders with low white blood cells
At the other extreme is a decreased white blood cell count, technically called leukopenia. Predominantly, this low count is secondary to decreased neutrophils, a condition known as neutropenia.
The main risk is the greater vulnerability of the patient to infections. However, leukopenia can also be caused by a decreased value of lymphocytes.
A low neutrophil count is common in some ethnic groups, such as Jews, Yemenis, and Afro-descendants, without representing a disease state. On the other hand, in the pediatric age, neutropenia is usually caused by infectious processes and nutritional alterations, while in adults it is also related to the use of drugs.
Likewise, there are congenital conditions in which the number of neutrophils is low due to specific mutations. Clinical manifestations include recurrent infections that appear at an early age and predominantly affect the mouth and perianal region.
Healing problems and hepatosplenomegaly (enlarged liver and spleen) are another common finding in these patients.
There is a rare condition that appears quickly after taking medication, known as agranulocytosis. Although cases are rare, it is difficult to establish an incidence rate, since it depends largely on individual factors.