Diseases Treated By Stem Cell Transplants
Healthy Stem Cells
Stem cell transplants or stem cell therapy is the infusion of healthy cells into the body to replace diseased or dysfunctional cells. There are a few types of stem cell transplants, depending on the source of the stem cells. There are bone marrow transplants, embryonic stem cell transplants, and umbilical cord blood transplants.
The body's bone marrow is where most stem cells are naturally located. In a healthy body, bone marrow stem cells turn into red blood cells, white blood cells or platelets that reduce the risk of anemia, help the blood clot and minimize bleeding, and help fight infections However when the bone marrow is attacked by disease it loses its ability to make these vital blood cells, thereby necessitating a stem cell transplant.
Diseases Treated by Stem Cell Transplants
Cancer: A stem cell transplant is needed when the bone marrow is damaged or destroyed. High doses of chemotherapy and full body radiation used to treat cancer and kill cancer cells simultaneously destroy diseased cells in the body and in the bone marrow. Therefore before chemotherapy and radiation begin, blood is collected and then banked (stored frozen). Once cancer treatments are completed, the stored blood is returned to the body, where it resumes its role making blood cells.
Hodgkin's lymphoma, Non-Hodgkin's lymphoma, Multiple Myeloma, Leukemia, Aplastic Anemia: Stem cell transplants have been successfully used to treat these diseases, which damage or destroy bone marrow. Other diseases being considered for stem cells treatments include diabetes, sickle cell diseases, Parkinson's, and thalassemia. Still in the experimental stage are stem cell transplants to treat solid tumors found in diseases such as breast cancer and testicular cancer.
Stem Cell Transplant Process
In order to treat diseases, stem cell transplants infuse healthy stem cells into the body intravenously. If the stem cells come from a person's own body, the process is called an autologous stem cell transplant. When stem cell transplants use stem cells from another person (donor), the process is called an allogeneic stem cell transplant. In the latter case, the donor's immune system should closely match the recipient's, and therefore a relative (i.e. a sibling) may be the best candidate.
Stem Cell Transplant Considerations
In general, autologous transplants (the use of one's own cells in a stem cell transplant) are less likely to result in complications than allogeneic transplants since the body will not reject its own stem cells. However, if a person's own blood or marrow contains some diseased or cancerous cells (the very cells one is trying to replace in the transplant), then autologous transplants carry a greater risk of relapse. Therefore a person with an aggressive form of cancer that has spread to many areas of the body may need to use stem cells from a donor.
Today studies are underway to determine whether treating one's own bone marrow or blood with certain drugs before they are infused back into the body will solve this problem. This procedure is known as purging, and the jury is still out on whether purging increases the success rate of autologous stem cell transplants.