What does the bone marrow do?
Bone marrow is a soft, spongy tissue found inside some bones in the human body, such as the crest of the ilium (or iliac crest), the sternum and skull.
- Microscopic view of the bone marrow of a healthy person
- Microscopic view of the bone marrow of a patient with ALL
The bone marrow can be transplanted because it can be extracted from the bone of a living donor, generally from the hip, by means of syringe aspiration, and if there is a human leukocyte antigen (HLA) system compatibility (compatibility between the donor and the receiver) it can then transferred to the receiver's circulatory system. The transfused stem cells lodge in the bone marrow of the recipient's bones. It is called a bone marrow transplant.
In order to minimise any possible side effects, doctors try to transplant stem cells that are most compatible with those of the patient. Everybody has a different set of proteins, called human leukocyte antigens (HLA) on the surface of the cells. These HLA proteins can be identified by means of special blood tests.
The larger the number of compatible HLA antigens, the greater the possibility that the patient's body will accept the donor's stem cells.
The patient's close relations, those of brothers and sisters particularly, are more likely to be HLA compatible than others who are not family members. However, only one patient in four has a compatible family member. The others must have recourse to a bone marrow donor registry such as REDMO, in Spain, which is administered by the Josep Carreras Foundation.
The bone marrow contains immature cells called hematopoietic stem cells. These are the stem cells that form the blood. They divide to create more cells, thereby producing all the cells in the blood, becoming one of the three kinds of blood cell: white blood cells that defend the body against infection; red blood cells that transport oxygen around the body; and platelets, which help the blood to coagulate.