[Cellular therapy for intensification in oncology and hematology: manipulation of peripheral blood stem-cell...

Peripheral blood stem cells transplantation after high dose chemotherapy is increasingly used for the treatment of hematological malignancies and solid tumors. Autologous transplantation are now used as first line therapy. The use of hematopoïetic growth factors allowed to collect peripheral hematopoietic progenitors in quantity large enough for several autologous reinfusions. As for bone marrow, peripheral blood stem cells allow fast and long-term hematopoietic reconstitution. The fast regeneration is strictly correlated to the number of hematopoietic progenitors infused. Some questions are still opened anyway, notably about the tumoral contamination of the graft which has been clearly demonstrated. Even if residual tumor cells are clearly shown to participate to relapse, the interest of ex vivo purging is still matter of debate. Several techniques of positive selection are now available, selecting normal stem cells thanks to the CD34+ antigen. Negative selection is also available either using clinical purging or monoclonals antibodies against tumoral antigens. Endly, ex vivo expansion of hematopoietic stem cells is under investigation using medical progress in the field of growth factors. Therefore, improvement of mobilisation protocols, of technology for positive or negative selection, as well as the strategy for ex vivo expansion will be the tools for the development of the treatment of some hematological malignancies and solid tumors reducing the hematopoietic and extra hematopoietic toxicity.