Transplantation potential of peripheral whole blood primed by VACOP-B chemotherapy plus filgrastim (r-metHuG-CSF) in patients with aggressive non-Hodgkin's lumphoma

Successful liquid storage of peripheral blood stem cells at subzero non-freezing temperature

Although non-frozen storage of peripheral blood stem cells (PBSC) has been extensively studied and utilized clinically, the optimal storage conditions have not been determined. In order to improve the maintenance of clonogenic capacity during storage, we evaluated the feasibility of subzero non-freezing preservation of PBSC and attempted to determine the optimal conditions. Human PBSC were stored in different non-cryopreserved conditions. University of Wisconsin (UW) solution was used as the storage medium for PBSC. The stem cell integrity was optimally maintained when PBSC were preserved in a supercooled state at -2 degrees C in UW solution without any cryoprotectants, and the highest values for nucleated cell survival (91.6%), CFU-GM survival (67.3%) and trypan blue viability (92%) were achieved at 72 h. CFU-GM survival in our storage conditions was significantly better than the survival achieved with hypothermic preservation in autologous serum and ACD-A solution at 4 degrees C (67.3 +/- 9.2% vs 42.9 +/- 15.3%; P < 0.01) or cryopreservation at -80 degrees C (67.3 +/- 9.2% vs 52.7 +/- 10.7%; P < 0.01). Thus, the combination of supercooling and UW solution was the optimal non-freezing method of preserving transplantable PBSC tested here. This method is of clinical utility in peripheral blood stem cell transplantation (PBSCT) for its simplicity and storage efficiency, and has value as a short-term storage method for PBSC to support dose-intensive multicyclic chemotherapy.

A single-step colony-forming unit assay for unseparated mobilized peripheral blood, cord blood, and bone marrow

The colony-forming unit (CFU) assay is exposed to a lot of variation, part of which is introduced by several enrichment strategies that are routinely performed before assessment of clonogenic capacity in mobilized peripheral blood (PB), bone marrow (BM), or cord blood (CB). We investigated the possibility to perform a single-step CFU assay by direct plating of PB, BM, or CB into CFU culture medium to obtain more reproducible results than after a standard Ficoll or lysis procedure. Direct plating implies the presence of red blood cells (RBC), white blood cells (WBC), and plasma in the CFU assay, which could possibly influence the outcome of the assay. Of all components, only the RBC was found to negatively influence CFU-GM growth if a concentration of > 0.02 x 10(9)/ml was present in the CFU culture medium. Subsequently, depending on the RBC concentration PB, BM, and CB samples were prediluted in triplicate or quadruplicate and plated into CFU medium. Lysis and/or Ficoll procedures were also performed in triplicate or quadruplicate on the same samples, and the mean colony number and coefficient of variation (CV) of the three techniques were compared. Significantly smaller CV values were found using the direct plating technique (all assays, mean 7.5%, range 1.6-15.6%) than after Ficoll separation (mean 18.0%, range 2.2-62.5%). Intermediate results were obtained with the lysis method (mean CV 11.6%, range 3.3-29%). In most samples, and especially in those with a very low number of clonogenic cells per milliliter, more colonies were detected with the direct plating method than with either the lysis or Ficoll method. In conclusion, the single-step direct plating method significantly enhances reproducibility of the CFU assay for PB, BM, and CB samples in comparison with standard techniques by circumvention of loss of colony formation and by decreasing variability. Furthermore, the direct plating technique is a timesaving assay.

Storage of unprocessed G-CSF-mobilized whole blood in a modified Leibovitz's L15 medium preserves clonogenic capacity for at least 7 days

Autologous stem cell transplantation using unprocessed, G-CSF-mobilized whole blood (WB) is a simple, cost-reducing procedure and supports high-dose chemotherapy regimens not exceeding 72 h. Thereafter, clonogenic capacity rapidly decreases if routine anticoagulants are used for storage. In order to increase clinical applicability, we investigated the requirements for optimal preservation of unprocessed WB for 7 days. During storage at 22 degrees C in CPDA-1, a decrease in pH was noted, which was at least partially responsible for the low recovery of clonogenic cells. Subsequently, WB cells were stored in various cell culture media (RPMI 1640, alpha-MEM, X-VIVO15, CellGro SCGM and Leibovitz's L15 medium) containing either serum, serum-free substitutes or no additives. Leibovitz's L15 showed significantly better CFU-GM recoveries than the other media. Using a calcium-free modification of L15 medium (added 3:10 to WB), 94 +/- 24% of CD34(+) cells, 41 +/- 14% of BFU-E, 56 +/- 17% CFU-GM and 90 +/- 14% of LTC-IC were preserved during storage for 7 days at 22 degrees C. Storage at 4 degrees C was also feasible, but showed less optimal recoveries of 52 +/- 29% (CD34), 32 +/- 10% (BFU-E), 13 +/- 7% (CFU-GM) and 58 +/- 9% (LTC-IC). The expression of CD38, Thy-1, c-kit, AC133, L-selectin and CXCR4 on CD34-positive cells remained unchanged. In conclusion, a modified Leibovitz's L15 medium better meets the metabolic requirements of a high-density cell culture and allows safe storage of G-CSF mobilized WB for at least 7 days. The results encourage further exploration of WB transplants stored for 7 days for clinical use.