Leukoblasts: what are they and how do they relate to other cells in leukemia?

Let's see what leukoblasts are and how they give rise to health problems through leukemia.

The human immune system is essential to understand our permanence over time, both as individuals and as a species. We have an innate component, which protects us in a general and non-specific way against pathogens, and an acquired component, which is refined the more we are exposed to specific microorganisms.

In the group of innate immunity we find physical barriers (such as skin and mucous membranes), chemical barriers (vaginal or sweat pH, for example), biological barriers (colonies of commensal bacteria that prevent the growth of others) and specific cellular bodies, such as neutrophils, macrophages and Natural Killer cells.

On the other side of the coin (but largely interconnected with the innate variant) we find acquired immunity, clearly represented by B and T lymphocytes. These are essential for specific responses to pathogens, as they can cause apoptosis of transformed infected cells, but also to "remember" a specific germ and respond better to it in successive situations. Do you know what happens when this system fails? Stay with us, because we explain it to you by means of leukoblasts.

What are leukoblasts?

Do not think that this initial question is easy to solve, because it seems that there is a clear disparity in terms of conceptual approach according to the portals consulted. In the first instance, one might think that the term "leukoblast" accepts different meaningsamong which we have found the following:

• An immature leukocyte.
• A cell that generates leukocytes. This definition does not seem entirely adequate, since in professional circles this cell type is known as hemocytoblast.
• An immature hematopoietic cell, which proliferates abnormally during leukemias.

Pulling the thread, one discovers that neither the first nor the second definition is entirely adequate, although the first is quite close. A leukoblast is, unequivocally, an immature cell that occurs during acute myeloid leukemia.. Once we have elucidated what the term itself is, it is of great interest to dive into the pathology that leads to its appearance. Before doing so, let us look at the normal pathway of a white Blood cell.

Differences between mature leukocyte and leukoblast

All white blood cells are produced in the bones. Although externally hard, they have a soft nucleus, which is known as bone marrow. All circulating cells in the blood (including red blood cells) arise from one cell type: the pluripotent hematopoietic stem cellalso known as hemocytoblast. This structure is therefore essential for understanding the human immune system.

Bone marrow tissue occupies approximately 4% of the total mass of a human being. To give you an idea of its frenetic activity and efficiency, about 500 billion red blood cells are produced here every day, no more and no less. Finally, it should be noted that a single hemocyteblast can give rise to a practically unlimited number of leukocytes throughout its cycle..

B lymphocytes form and mature in the bone marrow itself, while immature T cells leave this tissue and travel to the thymus to obtain their functionality, becoming transiently thymocytes. Once mature, they begin to "patrol" the blood, searching for antigens (substances of the pathogen that generate an immune response) with which to react.

In a completely different prism than normal, immature immune cells, known as leukoblasts, rarely proliferate excessively in the bone marrow and peripheral blood. This proliferation displaces normal hematopoietic tissue, resulting in bone marrow failure..

Acute myeloid leukemia (AML)

It is estimated that, during the year 2021, 60,000 cases of leukemia will be diagnosed in the United States alone, in addition to more than 23,000 deaths directly caused by this disease. Among all these types, acute myeloid leukemia will account for about 20,000 cases, or ⅓ of the total. AML will kill 11,000 people.

Despite the catastrophic data, acute myeloid leukemia is considered to be very rare, accounting for only 1 percent of all total cancers. The vast majority of people who present it are adults, since the average age of diagnosis is 68 years (rarely below 45).

In this pathology, as we have said, immature leukoblasts multiply uncontrollably within the bone marrow and their proliferation is such that, over time, they end up replacing healthy blood cells. As a result, the patient is much more likely to suffer from healthy infections, as well as to bleed excessively from small cuts and injuries.

Therefore, this type of neoplasm is considered a cancer of both bones and bones, this type of neoplasm is considered a cancer of both the bones and the blood.. Although in many cases there is no medical consensus on its cause, certain predisposing factors have been detected. Some of them are the following:

• Exposure to certain harmful chemicals and substances. Some types of radiation fall into this category.
• Smoking: Tobacco contains benzene, a chemical that has long been considered carcinogenic.
• Genetic disorders: certain congenital disorders, such as Down syndrome, are correlated in some cases with acute myeloid leukemia.
• Previous cancer treatments: as ironic as it may sound, a person who has gone through cancer may relapse in the form of AML due to radiation and chemotherapy.

Common symptoms of the presence of circulating leukoblasts

Leukoblasts crowd out all other normal functioning leukocytes, including platelets and lymphocytes.including platelets and lymphocytes. We say this because it is extremely common for patients to present with continuous bleeding and repeated infections over time.

Most people suffering from AML report general fatigue, malaise, headache and dizziness, due to the deficit of circulating red blood cells in the blood. In addition, it is striking to know that up to 80% of patients present fever before the time of diagnosis and that 40% show some type of infectious condition. This is due, as you can imagine, to the lack of B lymphocytes, T lymphocytes, neutrophils and more cell types that can fight pathogens.

Prognosis

For people over 20 years of age, the survival rate 5 years after diagnosis is 24%.. For those under 20, the figure is slightly more positive, increasing to 67%. Patients are often subjected to well-known processes to eliminate cancer, such as radiotherapy, chemotherapy or targeted therapy. Unfortunately, this is a truly aggressive type of malignancy, where recovery is rarely an option.

One of the most "hopeful" approaches is stem cell transplantation.. In this medical procedure, the bone marrow that is producing the leukoblasts is destroyed and then replaced with tissue containing healthy pluripotent hematopoietic stem cells, which are responsible for producing the correct leukocytes in the correct proportions. In this way, it is hoped that both in the bone marrow and in the bloodstream, a gradual replacement of the leukoblasts with the relevant cell types will take place.

Unfortunately, this does not always work. One of the clearest risks of transplanting stem cells from a donor is the development of graft-versus-host disease.. In this, the immune cells of the healthy donor may recognize the patient's tissue as a threat, directing attacks toward it. As you can imagine, if severe, this erroneous immune reaction can further aggravate the patient's clinical picture.

Summary

As you may have noticed, the term "leukoblast" stands out for its complexity, as there does not seem to be a clear consensus as to what it means, depending on the media consulted. In any case, we must point out that in most reliable portals it refers to a type of immature cancer cell that divides uncontrollably, so we have adopted this meaning to present you with all the relevant information on acute myeloid leukemia.

Leukoblasts proliferate at such a rate that they cannibalize all other cell bodies, such as red blood cells, platelets and lymphocytes.. As a result, patients bleed easily, bruise all over the body, suffer recurrent infections and have continuous fevers and pain. Of course, this pathology is difficult to approach and, the prognosis, especially reserved in adult patients.

Bibliographic references:

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