Bone marrow is the tissue inside the flat bones (sternum, femur, iliac crest…). It contains what we call hematopoietic stem cells, which are the ones that give rise to the three types of mature cells that we see in the peripheral blood: leukocytes or white blood cells, red blood cells or red cells and platelets or thrombocytes.
Leukocytes defend us against infections; if the number is low, we will be infected more frequently. Low red blood cell counts lead to anemia; anemic people are usually more tired and have a poorer tolerance to exertion. Platelets prevent us from bleeding. People with low platelets may bleed more easily, either with small bruises or, eventually, without bruising at all.
Why is it important to donate bone marrow?
Allogeneic transplantation of hematopoietic progenitors (or stem cells) is currently the only curative treatment for many patients with some malignant and benign hematological diseases. For an allogeneic transplant to be performed, there must be a high degree of compatibility between the donor and the patient. Within the family, the relatives most likely to be compatible with the patient are siblings.
However, not all patients have a compatible donor and, with the reduction in the number of children per family, these possibilities decrease. If the patient does not have a compatible sibling, the next step in the vast majority of cases is to look for an unrelated donor. These unrelated donors are registered in the donor banks that exist in different European countries, in the United States, China, Japan…. This is why it is important to donate.
How can stem cells be obtained?
The stem cells needed for a transplant can be collected from different places: firstly, directly from the bone marrow, which is where they are found in the greatest quantities. Bone marrow extraction is performed in an operating room, under local or general anesthesia, and consists of multiple punctures in the anterior and posterior iliac crests. Peripheral blood progenitors can also be collected. The bone marrow must be stimulated to release these progenitors into the blood. Hematology specialists perform this using a medication called granulocyte colony stimulating factor that allows the bone marrow to release the cells into the blood. Occasionally, cells obtained from umbilical cord blood can also be used.
Who can be a bone marrow donor?
Healthy adults can, in principle, be bone marrow donors. Obviously, there are very strict exclusion criteria because it is necessary to ensure that the potential donor is healthy. In Spain, the Josep Carreras Foundation and the REDMO (Spanish Bone Marrow Donor Registry) are in charge of managing the entire donation process.