NEW STRATEGIES IN HEMATOPOIETIC STEM-CELL TRANSPLANTATION - G-CSF-MOBILIZED UNPROCESSED WHOLE-BLOOD

Transplantation of mobilized peripheral blood stem cells (PBSC) for re scue of bone marrow function after high-dose chemo-/radiotherapy is wi dely used in hematologic malignancies and solid tumors. Mobilization o f stem cells to the peripheral blood can be achieved by cytokine treat ment of the patients. The main advantage of autologous PBSC transplant ation over bone marrow transplantation is the faster recovery of neutr ophil and platelet counts. The threshold number of PBSC required for a dequate rescue of bone marrow is thought to be about 2 x 10(6) CD34(+) cells/kg, if the stem cells are collected by leukapheresis and subseq uently cryopreserved. We show that this critical number could be furth er reduced to as few as 0.2 x 10(6) cells/kg. In 30 patients with mult iple myeloma and 25 patients with bad risk lymphoma 1 liter of granulo cyte colony-stimulating factor (G-CSF)-mobilized unprocessed whole blo od (stored at 4 degrees C for 1-3 days) was used for transplantation. Compared to a historical control group, a significant reduction in the duration of neutropenia, thrombocytopenia and the length of hospital stay was documented. Furthermore, the effect of stem cell support was reflected by a lower need for platelet and red cell transfusions and a reduced antibiotic use. Considering the data as a whole, a cost savin g of about 50% was achieved, To date, this easy to perform method of t ransplantation is only feasible following high-dose therapies that are completed within 72 h, since longer storage of unprocessed blood is a ccompanied by a substantial loss of progenitor cell function. Ongoing investigations include attempts to prolong storage times for whole blo od.