Collection and cryopreservation of mononuclear blood leukocytes and of CFU-C in man.

For bone marrow reconstitution after hemopoietic failure as a consequence of the action of a variety of etiological factors, hemopoietic stem cells are needed. These have been derived in the past mainly from bone marrow. This report describes studies and their results that indicate that granulocytic progenitor cells, measured in cell culture systems as "colony forming units in culture - CFU-C", can be collected in large quantities from the peripheral blood of human blood donors by continuous flow leukapheresis. They can be stored at ultra-low temperatures. Their recovery rate after thawing and washing is better than 85%. In a canine model, evidence was obtained that the presence of CFU-C in a suspension of mononuclear blood leukocytes is also indicative for the presence of pluripotent hemopoietic stem-cells. Therefore it is suggested that stem cells can also be collected from human blood as an alternative source for bone marrow reconstitution.