A bone marrow transplant is a procedure used to treat certain types of cancer and some other diseases. Before the bone marrow transplant takes place, a person's bone marrow cells are destroyed with radiation or chemotherapy.
The cells that normally live in the bone marrow and that are responsible for making blood cells are then replaced. Bone marrow cells are blood cells that are located in the spongy center of bones. These include:
white blood cells that are important in boosting your immune system and fighting infections
red blood cells that carry oxygen throughout the body
platelets that are necessary for blood clotting.
Cells to replace your original cells can be taken from your blood or bone marrow before the procedure starts. Bone marrow cells also can be taken from a different person (a donor) whose cells are a good match for the person receiving the transplant (the recipient). A good match means certain chemical markers on the cells of both donor and recipient are as close as possible and thus minimizes the possibility that the cells will be rejected by your body.