What are hematopoietic cells?
The bone marrow is the spongy tissue that is inside the bones and is The blood factory. In the bone marrow there are hematopoietic stem cells, from which the rest of the blood cells are produced, which are:
Red blood cells: which carry oxygen from the lungs to the tissues.
White blood cells: Responsible for defending the body against infections.
Platelets: This prevents and controls bleeding if blood vessels are damaged.
Why is a transplant necessary and what are the types of transplants?
Transplanting allogeneic or another donor
- When the marrow does not work or does not produce some of the blood components.
- When the bone marrow produces blood tumor cells and does not let healthy ones occur.
Transplant autologous, when the donor is the patient
In the treatment of certain solid tumors, it is necessary to use very strong chemotherapy, intensively, which leaves the bone marrow damaged. Therefore, before starting chemotherapy, hematopoietic progenitors are removed from the child, they are properly preserved and reinfused, once the chemotherapy is finished so that the marrow re-fabricates the blood cells mentioned above.
What are the sources of hematopoietic parents?
These cells are found:
- In the bone marrow: they can be extracted by clicking on the hip bone which is rich in bone marrow. It is performed in the operating room and with general anesthesia.
- In the blood, under normal conditions, there are few hematopoietic stem cells. However, there is a medicine that, if we inject it for a few days, gets the cells out of the marrow into the blood. Subsequently, they are extracted using a technique called apheresis, which does not require anesthesia: a machine draws blood through the vein of an arm, processes it to separate the hematopoietic cells and, subsequently, returns the blood to the donor through a vein in the another arm.
- In the umbilical cord blood, there are numerous hematopoietic cells. Its collection does not carry a risk for the newborn or the mother. These cells are frozen and stored in banks for possible later use.
In allogeneic transplants, how is the donor chosen?
The choice will depend on the type of illness, the speed with which the transplant is needed or certain factors in the donor: age, infections, previous pregnancies, etc. which can influence the subsequent result.
In the first place, more compatible siblings are usually preferred, but the highest degree of compatibility with each sibling occurs in 25%, so it is often necessary to look for another donor, who may be another family member or a compatible but not related donor.
What are the phases of the transplant?
Conditioning: specific chemotherapy to empty the recipient’s medulla i.e the patient who will receive the bone marrow transplant and prepare it to accommodate the new cells.
Manipulation: in certain types of transplantation it may be necessary to select or remove some cells to obtain better results.
Infusion: it is done through a catheter or central venous route, similar to a transfusion. Subsequently, hematopoietic cells travel to the bone marrow, where they start the production of blood cells.
Aplasia: Due to conditioning and until the new bone marrow begins to function, the child is in a situation where he is more vulnerable to infections and often needs transfusions. Therefore it remains in isolation. Visits are limited and hygiene measures must be extreme.
Hematological recovery: when the marrow that has been transplanted begins to work and the effective production of blood cells begins, it is already possible to leave the home.
Immune reconstitution: the transplant does not end the discharge. In the first months:
Transplanted blood cells responsible for immunity must learn to tolerate the patient’s cells, with the risk of graft versus host disease; other times they can be lost as in graft failures.
Blood cells must defend the body against possible external aggressions, while there is still a risk of infection.