Semiautomated processing of bone marrow grafts for transplantation

This report describes experience with a technique for the isolation of mononuclear cells from large quantities of human bone marrow using a blood cell processor. The procedure includes the separation of the bone marrow aspirates by concentrating and collecting interface buffy coat cells. A mononuclear white cell-enriched fraction is then obtained with ficoll-hypaque in the blood cell processor. Finally, the bone marrow white cells are washed to remove the ficoll-hypaque and the contaminating plasma. The entire procedure is carried out in a closed system. The automated method of isolating mononuclear cells proved superior to the manual method in both the recovery of cells and the time needed to process the marrow. Also, the risk of microbial contamination is substantially reduced. When marrow white cells processed by this method and cryopreserved were transfused subsequently into patients who had previously undergone high-dose chemotherapy and radiotherapy, engraftment, as indicated by a rise in the absolute granulocyte count of greater than 1000 per mm3, occurred within 20 days. This semiautomated technique provides a convenient, rapid, and reliable method for processing and preparing large numbers of viable marrow cells.