Definition
People who can benefit from a bone marrow donation are patients with leukemia, also known generally as blood cancer, such as acute myeloid leukemia or acute lymphocytic leukemia. In the course of bone marrow donation, blood stem cells (hematopoietic stem cells) are passed on. Their location is primarily in the bone marrow, where the cells of the blood, such as red blood cells (erythrocytes), are produced through cell division and cell differentiation.
This formation is called hematopoiesis. It is responsible for the continuous supply of blood cells. In the case of bone marrow or stem cell transplants, it is possible that the donor and recipient are one and the same person, i.e. the person concerned receives hematopoietic cells from himself. In this case, one speaks of an autologous transplantation. In an allogeneic transplantation, donor and recipient are two different persons (see: stem cell donation)
Autologous and allogenic transplantation
- In the course of an autologous transplantation, the patient receives his own hematopoietic stem cells. These are isolated from the blood or bone marrow before chemotherapy. If one intends to harvest them from the peripheral blood, the hematopoietic stem cells must be lured from their location, the bone marrow, by the administration of hematopoietic growth factors.
The hematopoietic growth factors are injected under the skin. The sought-after cells can then be separated from the blood using cell separators (leukapheresis). Tumor cells can then be differentiated from hematopoietic stem cells by means of special procedures, so that no tumor cells are introduced into the affected person during subsequent transplantation.
- Allogeneic transplantation requires a willing and tissue-compatible bone marrow donor.
In most cases, this type of transplantation is used if the patient’s hematopoietic stem cells have been completely destroyed by treatment measures. This is done within the framework of a myeloablative therapy, i.e. a therapy that leads to the destruction of the bone marrow and the hematopoietic stem cells enclosed in it. Usually, high-dose chemotherapy or radiation causes such destruction. Recently, however, allogeneic transplantation has also been used in patients whose hematopoietic stem cells have not been destroyed.
