Density gradient separation of hematopoietic stem cells in autologous bone marrow transplantation.

Recently, the principles of density gradient cell separation have been transferred to the marrow fractionation, and the Ficoll technique by using a COBE 2991 blood cell processor has been developed and widely employed as well. This method is particularly useful in view of a chemical antineoplastic purging intended for autologous marrow transplantation. Forty marrows, which derived from patients suffering with leukemia and lymphoma, were fractionated with Ficoll on a COBE machine and in vitro purged with Mafosfamide at a dose of 50 micrograms/ml/1 x 10e7 MN cells. The density gradient separation enables to reduce the initial volume to 10%, the contaminating RBC to less than 1%, the total nucleated cells to 25% (greater than 80% of MNC) sparing about 80% of the CFU-GM. After purging, the surviving hemopoietic progenitor cells were 2.5%. The clinical effects of the fractionated purged cells were studied in 11 autotransplanted patients and compared with 14 transplants performed with untreated buffy-coat marrow derived cells. Ficoll cells produced less adverse effects at the time of reinfusion, while, as expected, the time of hematopoietic recovery was delayed in these patients (mafosfamide treated cells). These results confirm the usefulness of the gradient density cell separation to reduce the side effects of the DMSO and to make reliable the Mafosfamide purging manoeuvre, preventing the interference of contaminating RBC aldehyde dehydrogenase.