Stem cells have the ability to divide persistently and develop into any type of cell in the body. A stem cell transplant is a complex procedure in which healthy stem cells are substituted for damaged stem cells.
The four chief sources of stem cells used for transplants are bone marrow, peripheral blood, umbilical cord blood and embryos.
The three types of stem cell transplants are autologous (in which healthy stem cells are recovered from the patient and given back to her), allogeneic (in which stem cells are donated by a non-related individual or immediate family member) and syngeneic (in which stem cells are taken from the individual's identical twin).
There are special proteins on the surface of all body cells called HLA (human leukocyte antigens). The closer these antigens match those of the donor and recipient stem cells, the greater the success rate.
The white blood cell count is typically low after treatment, and there is a higher risk of a patient getting an infection. Antibiotics may be administered for two to three weeks until the white blood cell count returns to normal.
Other side effects include anemia, loss of appetite, thrombocytopenia (bleeding), veno-occlusive disease (VOD), graft failure, interstitial pneumonia syndrome (IPS) and graft-versus host disease (GVHD). Other long term effects can include cataracts, infertility and new cancers.