Bone marrow harvesting has been the procedure traditionally used to obtain progenitor cells from the bone marrow. These same progenitor cells are present in small quantities in the peripheral blood and can be collected from peripheral blood through a procedure called apheresis. By giving a growth factor, such as Leukine, before apheresis, the number of progenitor cells in peripheral blood can be enhanced and the number the number of progenitor cells in peripheral blood can be enhanced and the number of apheresis procedures can be decreased. After a patient's progenitor cells are collected by apheresis, the cells are stored and later reinjected after high-dose chemotherapy with or without total body irradiation, to help repopulate the bone marrow. Using this procedure, larger numbers of PBPCs are collected which leads to more rapid engraftment.
Apheresis is less invasive than bone marrow harvesting and requires no anesthesia.