Biology of blood progenitor cells used in transplantation

Blood progenitor cells (BPC) are increasingly used in a variety of clinical settings. These include autologous and allogeneic transplantation after myeloablative therapy, and gene therapy. The optimal blood products for each of these applications have not been defined. The use of different cytotoxic drugs and cytokines, alone and in combination, results in the mobilisation of different total numbers and relative proportions of primitive and committed BPC. Some cytotoxics and cytokines not only are poor at mobilising BPC, but also are myelotoxic. Here we review the biology of BPC mobilisation and its implications for their clinical use.