Leukemia

Is leukemia hereditary?

No. Leukemia is associated with a lifelong acquired, not inherited, genetic change. Cases of relatives with the disease can be explained by the exposure of family members to a common cause. The risk factors for this type of cancer are:

  • smoking;
  • having Down Syndrome and other hereditary diseases;
  • exposure to radiation, such as from X-Rays and ratiation therapy;
  • chemotherapy (some classes of drugs);
  • having myelodysplastic syndrome and other blood disorders;
  • exposure to benzene, found in cigarette smoke, gasoline and chemical industries.
How is blood produced? What elements make it up?

Blood, in fact, is a mixture of cells that distributes itself in a yellowish, protein-rich fluid called plasma. Its primary function is to bring nutrients and oxygen to all the tissues of the organism and its absence is incompatible with life. Blood is produced inside the bones, in a region called the bone marrow, which, under normal conditions, never stops working. In the first years of life, all bones have the capacity to produce blood elements, but with advancing age, this function is reserved for the long and flat bones, such as the femur, humerus, ribs, sternum and hip. The process of blood production is called hematopoiesis.

In the bone marrow, there are cells that function as matrices. They are stem cell lines, why not say mother cells, from which all the blood components series originate. The main blood components are: plasma and formed elements, represented by red blood cells (or red blood cells), defense cells (or white blood cells) and platelets. Below are details about each of them.

Plasma: Plasma is basically composed of water, but it also contains nutrients, hormones, mineral salts and various proteins, which give it a yellowish color. Its function is to form a fluid medium to transport the formed elements, nutrients, salts, hormones and water to the body’s tissues.

RBCs (red blood cells): these structures, also known as erythrocytes, make up 40 to 50% of blood and give it the red color we see. Its main function is to carry the oxygen absorbed by the lungs to all the cells of the body and, at the same time, remove carbon dioxide, a toxic product of metabolism. Red blood cells only live for 4 months, but healthy bone marrow produces a staggering 4 to 5 billion red blood cells per hour to replace daily losses.

Leukocytes: white blood cells represent the body’s defense structures and are generically called leukocytes. They are of five types, neutrophils, lymphocytes, monocytes, eosinophils and basophils and are involved in the daily fight against bacterial and viral infections and any other situations that attack the body, such as cancer for example.

Platelets: These structures are also known as thrombocytes. In reality, they are not cells themselves, but fragments of the matrix cell in the bone marrow called a megakaryocyte. Its basic function is to stop bleeding when there is damage to the blood vessel wall. Normally, they circulate through the blood in an inactivated form, “monitoring” change points. When vascular injury occurs, endothelial substances activate platelets and plasma clotting factors. Thus, a cascade of processes begins that culminate in multi-platelet adhesion at the site and the formation of a natural healing mesh. The platelet thrombus prevents blood from leaking and also stimulates the repair process of the damaged blood vessel. The body really is an impressive machine.

What are lymphocytes?

Lymphocytes are one of the types of white blood cells (leukocytes) that make up the human body’s immune system. Like the other components, they are produced in the bone marrow and thymus, but are mainly stored in the lymph nodes (ganglia) and spleen, where they finish the ripening phase before entering the systemic circulation.

There are basically two types of lymphocyte cells: B-lymphocytes and T-lymphocytes. The former act remotely, that is, they do not participate in the melee fight against the invader. They are responsible for manufacturing antibodies, which, like personalized bullets, are proteins specifically targeted against certain proteins present in the offending agents. Viruses, bacteria and cancer cells, for example, when recognized as foreign, are potential victims of antibodies, either by direct destruction, by activating destruction enzymes present in the microenvironment, or even by attracting cells that enter the physical collision. Once activated, certain B lymphocytes maintain an immunological memory against the antigen, which speeds up the destructive process on second contact. This explains, for example, how vaccines work.

T cells, in turn, participate in the attack on the enemy, along with Natural killers (NK) lymphocytes, a third type of lymphocyte of the innate immune system, with a marked cytotoxic function. In addition, they produce substances that attract other defense cells to the place of combat. Neutrophils, dendritic cells, macrophages, monocytes, eosinophils, basophils, among others, enter the scene, each with a specific destructive function.

Lymphocytes, in fact, are the brains of the immune response and modulate all its aspects, determining when it starts, its intensity and the moment to stop the attack. When in perfect working order, this machine is able to protect us from the most diverse dangers.

What are the types of acute lymphocytic leukemia? What are the risk factors for acute lymphoblastic leukemia?

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children and accounts for nearly 30% of all childhood malignancies. In adults, however, it loses in frequency to acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL), representing 15% of the cases of these neoplasms. The disease is a product of malignant transformation of lymphocytes. The neoplastic clone derives, in 80% of cases, from a B lymphocytic progenitor, but it can also come from T cell lines, as in the other 20%.

The process begins in the bone marrow, where the population of malignant cells grows exaggeratedly, taking the place of healthy cells. The first serious consequence is the suppression of normal hematopoiesis. This generates the classic symptoms of the disease, characterized by anemia, low platelets and poorly functioning defense cells. It is worth remembering that, despite the excess of leukocytes, they are immature clones and, therefore, unable to perform their functions. Then comes a time when there is no more space in the bone marrow and young forms of lymphocytes, called blasts, begin to gain the bloodstream, being detected at alarming levels. This fact gives the disease its name: leukemia, which, literally, means excess leukocytes in the blood.

Acute lymphoblastic leukemia, despite manifesting in adults, is a disease characteristic of children, with a peak incidence between 2 and 5 years of age. It occurs more often in boys than in girls and is more common among white individuals than black individuals. Each year in the United States of America, about 4,000 new cases are diagnosed. Its survival rates have improved dramatically since the 1980s, and currently, the estimated 5-year survivors exceed 85% of cases.

In addition to what has been mentioned above, there are few risk factors related to the development of B-cell and T-cell acute lymphoid leukemias, and many of them are still not fully understood. The literature makes some considerations about the main ones, namely:

Genetic deficiencies: both Down Syndrome and type 1 neurofibromatosis, Bloom Syndrome, Ataxia/Telangiectasia Syndrome, Klinefelter Syndrome and Fanconi Anemia appear to be related to a significant increase in the risk of developing ALL;
Birth weight: A retrospective study from Sweden showed that the relative risk becomes greater with increasing birth weight. However, in this same series, the risk was even greater for those born weighing less than 1,500 g; – infections: HTLV-1 virus infection is clearly associated with a rare type of T-cell acute lymphocytic leukemia;
Identical twins with leukemia: when compared to the general population, an identical twin of an individual with ALL has an increased risk of developing the neoplasm, whereas non-identical twins do not have this relationship; – Chemicals: Exposure to chemical solvents such as benzene and certain chemotherapeutic agents increases a person’s chances.