Sources of Cells for Hematopoietic Cell Transplantation: Practical Aspects of Hematopoietic Cell Collection

Abstract Hematopoietic cell transplantation is based on the administration of a graft containing hematopoietic progenitor cells with the objective of restoring hematopoiesis after myeloablative chemotherapy and/or radiation, expediting hematologic recovery after intense, but not myeloablative therapy and/or replacing the patient hematopoietic system to provide immune surveillance and prevent recurrence of a hematologic malignancy. Hematopoietic grafts can be obtained from direct bone marrow harvesting, peripheral blood after mobilization of progenitor cells, or from stored cord blood units. In the allogeneic setting, each of these different sources of grafts is used with distinct implications for engraftment kinetics, risk of graft versus host disease, and relapse of the underlying hematologic malignancy. In the autologous setting, mobilized peripheral blood is near-universally used. Mobilization of progenitor cells to peripheral blood can be obtained by administration of higher doses of myeloid growth factors, chemotherapy plus growth factor, or growth factors plus the CXCR4 antagonist plerixafor. While growth factor alone is the simplest and less costly strategy, it is met by high rates of mobilization failure. Chemotherapy mobilization yields collection of more cells, but at higher cost and with increased risk of infection during neutropenia and need for transfusion support. Growth factor plus plerixafor successfully mobilizes adequate number of cells in the vast majority of patients with predictable kinetics, but at high cost. A strategy of adding plerixafor to an ongoing mobilization with growth factor depending on CD34+ enumeration in peripheral blood is feasible and can reduce costs.