Long-term cryopreservation of bone marrow for autologous transplantation.

Little is known about the effect of long-term cryopreservation on the viability of hematopoietic stem cells (HSC) or on the success of autologous bone marrow transplantation. Although progenitor cell assays such as culture of CFU-GM after thawing can be predictive of engraftment, the most rigorous assay for the cryosurvival of HSC is engraftment after reinfusion of stem cells. We retrospectively evaluated the engraftment data for 36 patients with hematologic malignancies or solid tumors treated at the Fred Hutchinson Cancer Research Center between 1981 and 1993 who received bone marrows stored for 2 years or more. The median duration of cryopreservation for this study group was 2.7 years (range 2.0-7.8). Ninety-seven percent of patients in the study group achieved a granulocyte count of > or = 0.5 x 1.0(9)/1 at a median of 19 days (range 10-115) vs 86% of control group (selected by diagnosis and date of storage) at a median of 20 days (P = 0.14). Seventy percent of patients in the study group achieved a platelet count > or = 20 x 10(9)/1 at a median of 27 days (range 9-69) vs 74% of control group at a median of 23 days (P = 0.47). Also, samples of 28 marrows cryopreserved for a median of 4.4 years (range 2.0-7.8) were cultured to determine if a loss of hematopoietic progenitors relative to duration of storage could be detected. The storage length was not predictive for the quantity of colonies formed (P = 0.57 for BFU-E-derived colonies; P = 0.65 for CFU-GM-derived colonies). We found no consistent detrimental effect of long-term cryopreservation on the success rate of autologous bone marrow transplantation. This report confirms previous reports that marrow cells cryopreserved for several years are capable of engrafting. Therefore, bone marrow cells may be stored at an early appropriate time before the side-effects of multiple cycles of chemotherapy and radiotherapy on hematopoietic tissues are incurred.