Stem Cell Sources Stem Cell Sources Stem cells are immature cells generally found in bone marrow. If the transplant is successful, the donated stem cells will grow in number and restore the recipient's marrow and its blood-forming function. Unless a physician specifies otherwise, all three stem cell sources are considered when a search of the NMDP Registry is initiated. Marrow Marrow is removed from the upper area of the donor's pelvic bone while the donor is under general or regional anesthesia. On average, one liter of marrow is removed.
Stem cells are also present in the blood stream, though in much smaller amounts than in the marrow.
A growth factor such as Filgrastim can be injected into donors to stimulate a sufficient numbers of stem cells for a transplant. These peripheral blood stem cells are then collected through apheresis. The physician seeking a stem cell transplant for a patient makes the decision to request marrow or PBSC from an NMDP donor. Under the protocols the NMDP has submitted to the FDA, if an NMDP volunteer agrees to donate PBSC, he or she will receive Filgrastim injections. The peripheral blood stem cells will then be collected in one or two apheresis sessions.