A bone marrow transplant delivers healthy bone marrow stem cells, the cells that produce all of the blood cells of the body, to a person who needs them. Instead of through a surgical procedure, a bone marrow transplant is done via an IV, sending the cells into the bloodstream. The new cells travel through the blood to the bone marrow where they take up residence and begin producing healthy red and white blood cells. The bone marrow stem cells can come from a donor, umbilical cord blood, or from marrow that was previously removed from the patient himself.
Blood Cancers
Some types of blood cancers affect the stem cells inside bone marrow that produce specific types of immune cells. Multiple myeloma is a type of cancer that affects the plasma cells in blood, white blood cells also known as B cells, which normally operate in the immune system to produce antibodies. Leukemia and lymphomas are groups of cancers that can affect many different immune cells, including B cells, T cells and NK cells.Transplanting new bone marrow into a patient with these cancers can cause the individual's bones to produce healthy cells instead of cancerous cells, and effectively cure the cancer.
Blood Disorders
Apart from cancers, other disorders of the blood can arise in the bone marrow stem cells that may be treated using a bone marrow transplant. Sickle cell anemia and thalassemia are two inherited blood diseases that cause malformed red blood cells that cannot survive for long, resulting in severe anemia and other symptoms. Aplastic anemia, an insufficient production of red blood cells, may be another reason for a bone marrow transplant. Immunodeficiency diseases occur when the marrow does not produce the correct type or number of immune cells, or white blood cells. These diseases are rare, but can be fatal to people who have them and do not receive a bone marrow transplant. One example is severe combined immunodeficiency disease, or SCIDS, which is commonly known as the "bubble boy disease" due to the need for patients to live inside a sterile bubble to avoid the risk of contamination with infections that could kill them.
Chemotherapy or Radiation Damage
People who are undergoing chemotherapy or radiation treatment for cancer may end up with damaged or destroyed bone marrow. If this happens, their own marrow becomes unable to produce blood cells, leading to secondary diseases such as anemia or immune deficiencies. These patients often require a bone marrow transplant to correct the problem, often transplanted from their own cells that were saved before cancer treatment began. This is called a rescue bone marrow transplant.
