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

The human immune system is essential for understanding our permanence over time, both as individuals and as a species. We present an innate component, which protects us in a general and non-specific way against pathogens, and another acquired, which is perfected as we are exposed to specific microorganisms.

In the group of innate immunity, we find physical (such as skin and mucous membranes), chemical (vaginal pH or sweat pH, for example), biological (colonies of commensal bacteria that prevent the growth of others) and biological barriers. specific cell 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 pathogen-specific responses, as they can cause cell apoptosis. Transformed infected cells, but also to “remember” a particular germ and better respond to it in successive situations. Do you know what happens when this system fails? Stay with us, we’ll tell you through leucoblasts.

    What are Leucoblasts

    Do not think that this initial question is easy to solve, because there seems to be a clear disparity in terms of conceptual approach according to the portals consulted. At first, you might think that the term “leucoblast” accepts different meanings, Among which we found the following:

    • An immature leukocyte.
    • A cell that generates leukocytes. This definition does not seem quite appropriate, because in professional circles this type of cell is called a hemocytoblast.
    • An immature hematopoietic cell, which proliferates abnormally during leukemia.

    Pulling on the string, we discover that neither the first nor the second definition is quite adequate, although the first is quite close. A leucoblast is unequivocally an immature cell that presents with acute myeloid leukemia. Once we have elucidated what the term itself is, we see that it is of great interest to delve into the pathology that leads to its appearance. Before that, let’s see what is the normal path of a white blood cell.

    Differences between mature leukocytes and leucoblasts

    All white blood cells are produced in the bones. Although on the outside they are hard, they have a soft core, called the bone marrow. All cells circulating in the blood (including red blood cells) come from one type of cell: the pluripotent hematopoietic stem cell, Also known as hemocytoblast. Therefore, this structure is essential for understanding the human immune system.

    Bone marrow tissue occupies about 4% of a human’s total mass. To give you an idea of ​​its rampant activity and effectiveness, we’ll tell you that around 500 billion red blood cells are produced here every day, no more and no less. Finally, it should be noted that a single hemocytoblast can cause a virtually unlimited number of white blood cells throughout its cycle.

    B cells form and mature in the bone marrow itself, while immature T cells leave this tissue and travel to the scam to gain its functionality, transiently becoming thymocytes. Once mature, they begin to “patrol” the blood, looking for antigens (substances in the pathogen that generate an immune response) with which to react.

    In a completely different prism than normal, immature immune cells, called leucoblasts, proliferate disproportionately in bone marrow and peripheral blood. This proliferation displaces normal hematopoietic tissue, resulting in spinal cord failure..

      Acute myeloid leukemia (AML)

      It is estimated that by 2021, 60,000 cases of leukemia will be diagnosed in the United States alone, in addition to more than 23,000 deaths directly from the disease. Of all these types, acute myeloid leukemia will account for approximately 20,000 cases, or 3/4 of the total. AML will kill 11,000 people.

      Despite the catastrophic data, Acute myeloid leukemia is considered very rare, accounting for only 1% of all cancers. The vast majority of people with it are adults, as the average age of diagnosis is 68 (rarely below 45).

      In this pathology, as we have said, the immature leukoblasts within the bone marrow multiply uncontrollably and their proliferation is such that over time they eventually replace healthy blood cells. As a result, the patient is much more likely to suffer from healthy infections, as well as excessive bleeding due to small cuts and wounds.

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

      • Exposure to certain chemicals and harmful substances. This category includes certain types of radiation.
      • Smoking: Tobacco contains benzene, a chemical that has long been considered a carcinogen.
      • Genetic disorders: Some congenital disorders, such as Down syndrome, are in some cases correlated with acute myeloid leukemia.
      • Previous Cancer Treatments: As ironic as it sounds, a person who has had cancer can relapse as AML as a result of radiation therapy and chemotherapy.

      Common symptoms of the presence of circulating leukoblasts

      Leukoblasts displace other normal functional leukocytes, Including platelets and lymphocytes. We say this because it is extremely common for patients to experience continuous bleeding and repeated infections over time.

      Most people with AML report general fatigue, malaise, headaches, and dizziness, due to a deficiency of circulating red blood cells. In addition, it should be noted that up to 80% of patients have a fever before diagnosis, and 40% have some type of infectious disease. This is due, as you can imagine, to the lack of B lymphocytes, T lymphocytes, neutrophils and other types of cells capable of fighting pathogens.

      Provide

      For people over 20 years of age, the 5-year survival rate after diagnosis is 24%.. For those under 20, the figure is slightly more positive, rising to 67%. Well-known methods of ending cancer, such as radiation therapy, chemotherapy or targeted therapy, are often applied to patients. Unfortunately, we are faced with a truly aggressive type of neoplasm, where healing is rarely an option.

      One of the most promising approaches is stem cell transplantation.. In this medical procedure, the bone marrow that produces leucoblasts is destroyed and then replaced with tissue containing healthy pluripotent hematopoietic stem cells, responsible for producing the correct leukocytes in the right proportions. With this, it is expected that both the bone marrow and the bloodstream, there will be a gradual replacement of leucoblasts with the affected cell types.

      Unfortunately, this does not always work. One of the most obvious risks of a donor stem cell transplant is a graft versus host disease occurs. In it, the immune cells of the healthy donor can recognize the patient’s tissue as a threat, directing attacks on them. As you can imagine, if it presents itself severely, this erroneous immune response can further worsen the patient’s clinical picture.

      summary

      As you may have noticed, the term ‘leucoblast’ stands out for its complexity, as there does not seem to be a clear consensus on what it means, depending on the environment consulted. However, we have to point out that in most reputable portals it refers to an uncontrollably dividing type of immature cancer cell, so we have adopted this meaning to present all the relevant information about Acute Myeloid Leukemia.

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

      Bibliographical references:

      • Trist-Santiago, N., Arteaga-Ortiz, L., Roses-López, A., Aguayo, A., López-Karpovitch, X., and Crespo-Solís, I. (2010). INCMNSZ experience in adult patients with acute myeloid leukemia. 2003-2008 cohort. Rev Invest Clin, 62 (2), 100-8.
      • Lagunas-Rangel, FA (2016). Acute myeloid leukemia. A perspective on the molecular mechanisms of cancer. Mexican Journal of Oncology, 15 (3), 150-157.
      • Acute myeloid leukemia, geth.es. Collected December 27 from https://www.geth.es/pacientes/hemopatias/leucemia-mieloide-aguda
      • Acute myeloid leukemia, mayoclinic.org. Retrieved January 27, from https://www.mayoclinic.org/en-us/diseases-conditions/acute-myelogenous-leukemia/symptoms-causes/syc-20369109
      • Leyto-Creu, F. (2018). Acute myeloid leukemia. Hematol Méx, 19 (1), 24-40.
      • Pi Blanc, D., Macías Abraham, C., Lahera Sánchez, T., Marsán Suárez, V., Sánchez Segura, MDLC, de la Vall Pérez, LO, … and Martínez Machado, M. (2014). Immunophenotypic characterization of patients with acute myeloid leukemia. Cuban Journal of Hematology, Immunology and Hemotherapy, 30 (1), 27-35.

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