Lesser HLA matches may be considered based on available options and the patient's condition. With removal of T-Cells from the graft transplants between patients and donor who are mismatched for a single HLA allele can be quite successful with overall outcome differing little from the outcomes of fully matched unrelated transplants. Donor choice is a key factor in the success of the allogeneic transplant. The choice of donor, family member or unrelated, fully HLA matched or partially HLA matched, will include the entire transplant team, together with you and your physician, after weighing all relevant factors. Each source has advantages and disadvantages.
Stem cells are resident in the bone marrow, since that is where new blood cells are normally made.
Most allogeneic transplants have been performed using marrow as the stem cell source, so harvest and processing procedures are well established. The marrow harvest procedure is safe, but does require that the donor undergo general anesthesia, which poses a small risk. Stem cells can be readily mobilized into the circulation by treatment of normal donors with blood cell growth factors. Apheresis allows the selective collection of the stem cell enriched fraction, while returning the red blood cells and plasma to the donor. A higher number of stem cells than that obtained in an average marrow collection is most often collected and no donor anesthesia is required.