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Medical researchers are making great strides in treating serious diseases, affording physicians with new techniques, procedures, and technologies. Cord blood transplants are one example which is showing great promise for treating serious and often fatal diseases such as leukemia, sickle cell anemia, lymphoma, immune system disorders, and neuroblastoma. Cord blood, the blood that remains in the umbilical cord after a baby is born, is rich in stem cells, which have proven to be an effective alternative in treating diseases that would otherwise require a bone marrow transplant. There are three types of transplants:
- Autologous transplants: patients receive their own stem cells.
- Syngeneic transplants: patients receive stem cells from their identical twin.
- Allogeneic transplants: patients receive stem cells from their brother, sister, or parent. An unrelated donor also may be used.
Since the first cord blood transplant in 1988, thousands of cord blood stem cell transplants have been successfully performed, but transplants attempted with a patient’s own umbilical cord blood remain extremely rare. Only three documented transplants have used the child’s own cord blood to treat neuroblastoma. Estimated odds of a child needing a cord blood stem cell transplant vary greatly, anywhere from one in 1,000 to one in 200,000.
Most cord blood transplants in the United States are performed on children because the amount of cord blood may not contain enough cells to treat adults, but research is expanding the possibility for adults, too. Current research in the field of transplant and stem cell therapy includes a focus on Parkinson's disease, stroke, diabetes, Lou Gehrig’s disease (ALS), spinal cord injuries, and cardiac repair.
After cancer ridden stem cells are destroyed by high doses of chemotherapy and/or radiation therapy, a cord blood stem cell transplant restores healthy stem cells to take the place of the cancer cells and build up the immune system. Cord blood stem cells, like bone marrow, develop into red blood cells, white blood cells, and platelets. Research also has shown cord blood cells can develop into brain, heart, and liver cells. The cord blood stem cells are able to replace other cells in the body that are abnormal, weakened, or destroyed by disease.
The Transplant Procedure and Post-Transplant Activity
Pre-Transplant Activity. Prior to a cord blood transplant, patients may have surgery to remove tumors and undergo multiple rounds of chemotherapy and/or radiation. Physicians hope the chemotherapy and radiation will rid the patient’s body of disease and allow the healthy, transplanted cord blood cells to take over.
Cord blood is obtained from a cord blood bank. Cord blood is originally collected from the umbilical cord at birth, approximately three to four ounces of blood is drawn from the umbilical cord and placenta, posing no risk to the child or mother. It is then kept frozen in a highly controlled environment at a public or private cord blood bank until needed. Public banks are searchable by physicians to find a match for their patients. Private banks reserve the cord blood only for the child and members of his/her family.
Transplant. The transplant process begins with the patient receiving a high dose of chemotherapy and/or radiation to eradicate any cancer that is left in the patient’s body, and to ablate the patient’s immune system as well. Then, the patient receives the transplanted stem cells intravenously, similar to a blood transfusion. The intravenous part of the transplant takes approximately 15 minutes.
Post-Transplant Activity. Once the stems cells have been transplanted into the patient, they enter the bloodstream traveling to the patient’s bone marrow. Through a process called “engraftment,” the stem cells start to produce new white blood cells, red blood cells, and platelets. The patient is typically kept in isolation for at least two to four weeks while the engraftment process occurs, though it can take months and even years for patients’ bodies to restore full immune function. Through blood tests, doctors are able to evaluate and confirm that the cancer has not returned and new blood cells are forming. All cord blood transplant patients have lowered immune systems after their procedures. Texas Oncology cord blood transplant patients stay in a state-of-the-art 13-bed hospital unit designed to keep infections out. In addition to specialized nursing, the unit has a water purifying system and air system with high-efficiency air filters designed to keep bacteria out and keep clean air in the unit.
Side Effects. Unfortunately, there are many side effects that could occur during the cord blood transplant process. Among them is an increased probability of infection and bleeding from the high dose of chemotherapy and radiation given prior to the transplant. Doctors give antibiotics to prevent or treat this possibility. Patients may also receive transfusions of platelets to prevent bleeding and red blood cells to treat anemia. Other short-term side effects include nausea, vomiting, fatigue, loss of appetite, mouth sores, hair loss, and skin reactions.
Long-term side effects caused by the high doses of chemotherapy and/or radiation therapy given prior to the transplant may include infertility, cataracts, new cancers, and damage to the liver, kidneys, lungs, and/or heart.
Sources: National Cancer Institute, National Cord Blood Program, and Journal of Pediatric Hematology/Oncology
Updated 01/28/2008