HEMATOPOIETIC STEM-CELLS - TECHNICAL AND METHODOLOGICAL CONSIDERATIONS

Peripheral blood cells containing large numbers of granulocyte-macrophage colony forming units (CFU-GM) can be collected by leukapheresis. The number of aphereses needed to collect 2-7 x 10(8) mononuclear cells (MNC)/Kg and 2-50 x 10(4) CFU-GM/Kg during rapid hematopoietic recovery following cytotoxic chemotherapy-induced myelosuppression depends on type of disorder, type of chemotherapy, patients' clinical conditions, cell pre-counts, concomitant growth factor administration, optimal timing of leukapheresis, vascular access apheresis machines, and type of technique used. Because of the advent of growth factors, a broader window for collection of progenitors has been provided. This has determined an increasing interest for peripheral blood stem cell (PBSC) autotransplants, along with increasing problems due to the number and types of procedures to be performed and the quality and purity of the products. Presently most of the basic technical problems are solved and an array of third generation cell separators is offered for collection of progenitors. Their common features are safety controls, closed circuits, automation, and mechanical and electrical reliability. Performance and quality of the product may be totally different depending not only on the apparatus, but also on the patients' clinical conditions. These technical aspects will be rapidly discussed having in the due considerations the expected increase in the number of procedures.