PROLONGED CRYOPRESERVATION OF HUMAN BONE MARROW

Abstract

We tested the viability of human bone marrow stored for 40 to 42 months in the vapor phase of liquid nitrogen. A median of 2 X 10(10) nucleated cells obtained from eight patients were concentrated to 1.3 X 10(10) using discontinuous centrifugation. These were stored in polyolefin bags in volumes of 100 to 500 ml using 10% dimethyl sulfoxide (DMSO) as cryoprotectant. Cell number and granulocyte - monocyte colony - forming cell (CFU-c) plating efficiency were determined before freezing and after thawing, after dilution and removal of DMSO, and after 2 to 4 hr of additional incubation. The median difference in cell number and CFU-c plating efficiency after this prolonged storage was -9 and +2%, respectively. Dilution, washing, and a 2-hr incubation were associated with cell losses of 24, 24, and 19% and increases in CFU-c plating efficiency, ranging from 22 to 79%. The number of viable CFU-c was never significantly lower than the number of CFU-c stored or initially thawed. Vapor phase storage appears to be adequate for prolonged human bone marrow cryopreservation using CFU-c viability as a determinant.