Leukocytes, also called white blood cells, are an important factor in the blood and a key part of the body's immune system. That is, they intervene and participate very actively in the defense of the body against infectious agents (antigens) or foreign substances. And they constitute, therefore, approximately 1% of the total volume of blood in the body of a healthy adult person. They complete the immune system of the human body and are present in the blood, lymph nodes, spleen, tonsils, adenoids, and in the lymphatic system.
What are leukocytes
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They are a type of blood cells that are produced by the bone marrow, responsible for the immune system's defenses against external aggressions, such as infectious bacteria or viruses. White blood cells are found throughout the body, including the blood and lymphatic systems.
White blood cells, which are leukocytes, are part of the body's immune system and according to the amount of them in the blood, it can be determined if there is any type of condition in the body, such as infection, allergy, inflammation and even leukemia. For the determination of the number of leukocytes in the blood, a complete blood count or CRS test is performed.
How are leukocytes produced
Leukocytes or white blood cells originate in the bone marrow and develop from so-called stem cells. Once mature, these cells transform into one of the five varieties of white blood cells: Neutrophils, Monocytes, Lymphocytes, Basophils, Eosinophils.
The production of blood cells is often regulated by body structures such as the lymph nodes, spleen, liver, and kidneys. During an infection or injury, it is when more white blood cells are produced in the blood, since their function is to combat any foreign agent that enters the body and alters its functions.
Leukocyte function
White blood cells are cells found in the bloodstream that are essential for health, especially for the immune system. The primary function of these cells is to circulate through the blood to fight infection, thus representing the body's immune defense and can sometimes attack normal body tissues. In addition, they produce antibodies called lymphocytes and participate in the destruction of microorganisms.
Types of leukocytes
There are three types of leukocytes that originate in the bone marrow from a pluripotential stem cell (which in turn generates other types of blood cells such as platelets and red blood cells). These leukocytes are: lymphocytes, granulocytes (neutrophils, eosinophils and basophils) and monocytes.
Among leukocytes we can distinguish:
- The highly mobile, polymorphonuclear granulocytes, which in turn are classified into neutrophils, eosinophils, and basophils.
- Lymphocytes, with a single nucleus and without granulation, mostly small, whose function is to contribute to the immune system, produce antibodies and destroy abnormal cells.
- Monocytes, large in size, very rich in enzymes and a single nucleus, kidney-shaped, with phagocytic mission.
Neutrophils
They are the most common cells in the blood system belonging to granulocytes, which are granules in the cytoplasm (part of the membrane that surrounds the nucleus). They make up almost 70% of the total white cells housed in the blood, they only live for 24 or 48 hours and their function is the immune defense as they are the first cells to go to the infected area in a period of time less than one hour. and this process is called chemotaxis.
These cells can also digest bacteria, but they cannot survive this; that is why the pus is composed of dead neutrophils and the bacteria that caused the infection already digested. The neutrophil count allows to know vital information to provide a diagnosis or control in the face of a disease, medical procedures such as chemotherapy, or in non-pathological situations.
Lymphocytes
These are responsible for defending the body from infections, being able to differentiate between foreign elements in the body and the cells that belong to the individual. These foreign bodies, also called antigens, are identified by lymphocytes; but not by any type of lymphocyte but by a specific one according to the type of antigen, and from there, the cell will generate chemical substances to fight the foreign agent.
The variety of lymphocytes that exist are:
- The B cells that give rise to plasma cells that produce antibodies.
- The T lymphocytes, are considered as mediators of cellular immune response, able to identify the specific antigen.
- Natural cytolytics, which contain granules with enzymes capable of destroying tumor cells or cells infected with some type of virus.
Monocytes
They are those that perform phagocytosis like neutrophils, but their duration is longer than these. In addition, monocytes present antigens to T lymphocytes so that they can identify them again and later be eliminated.
Eosinophils
These cells, which are part of granulocytes, move around and digest particles, specifically parasites. Similarly, they are the inflammatory cells that prevail during an allergy, such as during hives, rhinitis, an asthmatic episode or a parasitic infection; so during any of these conditions, the count of these cells will be high. However, a high number of eosinophils in some cases, can indicate some type of cancer.
Basophils
They are the least present types of leukocytes in the blood and are also granulocytes. Similar to eosinophils, the presence of a certain amount of basophils usually indicates an allergy or a parasitic infection. Its function is to act as immunological modulators in allergic episodes.
Leukocyte measurements
According to the amount or count of total leukocytes in the blood, the health of a patient can be determined. The method used for this is the urine test, which allows to know if there is any type of systematic or kidney disease.
The urine test is the method used to complement a diagnosis since the second century. It is a much less painful test than the blood test, since it consists of taking a sample of this painless liquid. This exam can reveal important clues about systemic and kidney disease.
High leukocytes
The presence of high leukocytes in the blood is called leukocytosis, and is characterized by a result of 11,000 / mm3 in blood tests. Its causes can be: excess stress, recent infections, allergies, rheumatoid arthritis, side effect of some medication, myelofibrosis or leukemia.
The symptoms of having high leukocyte are fever above 38 ° C, difficulty breathing, dizziness, loss of appetite and tingling in the arms and legs.
Low leukocytes
Low leukocytes or leukopenia occur when there are less than 4000 / mm3 in the blood. Some of the causes are: anemia, leukemia, lupus, chemotherapies, use of antibiotics, diuretics and a weak immune system due to suffering from HIV and malnutrition. Similarly, high white blood cells or leukocytes in urine are caused by pregnancy because the bladder can become contaminated.
The symptoms of suffering from low white blood cells are: excessive tiredness, constant fever, headaches, infections and recurrent colds.
Normal values of leukocytes
The index of normal values of leukocytes or white blood cells can vary between 4000 and 10,000 / mm3.
Leukocyte-related diseases
There is a significant number of conditions related to alterations in white blood cells, either due to a deficiency in their count or an excess, or simply due to their mere presence in the urine.
The presence of white blood cells or leukocytes in the urine indicates that there is a urinary infection, which could be caused by trauma, infectious agents, and infectious substances. They also indicate an infection or kidney deficiency, and can occur when urine is retained in the bladder for long periods of time, which can trigger wasting and infection of germs; as in the case of lupus nephritis. On the other hand, infectious conditions produced by bacteria such as Shigella, Clostridium difficile or Salmonella can occur, which will cause the presence of leukocytes in feces.
On the other hand, regarding the alteration in its blood count, leukocyte values can be altered by infectious episodes caused by diseases such as Acquired Immune Deficiency Syndrome (AIDS) or by stress conditions.
White blood cells and their various types can be evaluated in the same way through a laboratory study called hematology. Elevations of white blood cells well above their normal values are hallmarks of the disease known as leukemia. Some virus infections such as dengue can cause a significant decrease in white blood cells with a predominance of lymphocytes.
On the other hand, neutrophilia is a medical condition that is characterized by a high level of neutrophils in the bloodstream. These correspond to the white blood cells responsible for protecting the body from pathogens through an immune response. Its cause is some type of bacterial condition and its most common symptom is high fever, which may indicate a local infection. Rheumatic diseases, as well as neoplasia of the intestinal tract and lung, are the cause of neutrophilia.
