Children's experienced transfusion medicine specialists oversee peripheral blood stem cell collection (PBSC) procedures, performed by the Blood Donor Center's technical staff. The Blood Donor Center team is extensively trained in performing many therapeutic apheresis1 procedures on pediatric patients. More than 150 PBSC collections in the last 6 years have been performed by the center. Children's Hematopoietic Stem Cell Laboratory processes peripheral blood stem cells for blood and marrow transplantations.2
Stem cells are the cells within the body that constantly renew themselves and generate other cells of the body. Peripheral blood stem cells3 are the cells that come from a person's bone marrow4. Often these cells become much higher in blood after either chemotherapy5 (as a response to low blood counts) or after using growth factor-stimulating medicines.
Peripheral blood stem cell (PBSC) collection
Peripheral blood stem cell (PBSC) collection is a procedure where volunteer donors (relatives or siblings) or patients donate their stem cells through apheresis for allogeneic and autologous blood and marrow transplantation. At Children’s, most PBSC collections are for autologous transplants. A variety of diseases are treated particularly neuroblastoma and malignant brain tumors.
Stem cell apheresis
Apheresis is the process of extracting blood components from the peripheral blood with the help of a cell separator that divides blood into separate cell elements.
Because few stem cells travel in the bloodstream, it takes several hours (most within one day) to collect a sufficient quantity for transplantation. Children’s uses cutting-edge monitoring equipment in the Hematopoietic Stem Cell Laboratory that allows the stem cell transplant team to know precisely when, in real time during the procedure, the optimum quantity of stem cells have been collected.
Infants and young children may require ongoing sedation during the apheresis procedure, and in these cases only, stem cell collections occur in the pediatric intensive care unit (PICU). Older children undergo apheresis in the Blood and Marrow Transplantation inpatient unit at the hospital.
For those patients who do not have a special pheresis catheter in place, a temporary pheresis catheter is placed by the interventional radiologist or intensive care physicians on the morning of the collection and is removed after apheresis has been successfully completed. Patients are asked to refrain from eating or drinking prior to the placement of the catheter.
A patient is connected via their pheresis catheter to the apheresis machine (also called a cell separator). Blood is then circulated through the machine where stem cells are collected while the rest of the blood is returned to the patient. Because the size of the apheresis machine is relatively large compared to the patient, often blood is used to prime the apheresis machine. This blood may be donated from community donors or from friends, relatives or parents of the patient. The Blood Donor Centers can help arrange for this donation. This must be done at least three days in advance of the procedure.
During the procedure, many children sleep, read, play video games, or watch a movie on a portable DVD player. Parents are welcome to be at the bedside while the procedure is taking place.
Glossary of Terms
1 Apheresis: The process of removing only a selected type of blood cells from a blood donor and simultaneously returning all the others
2 Transplant: A medical treatment to replace a recipient’s diseased organ or tissues with a healthy organ or tissue from a donor
3 Peripheral Blood Stem Cells: Cells with the potential to produce all the components of blood. Peripheral blood stem cells (PBSC) are obtained from “circulating” blood rather than from bone marrow
4 Bone Marrow: The spongy center of bones that is the “factory” for all blood cells in circulation
5 Chemotherapy: Treatment for cancer using chemical substances designed to kill cancer cells. It is used in large doses to help destroy a patient’s diseased marrow in preparation for a marrow transplantView full glossary