Liquid Storage of Hematopoietic Stem Cells Versus Proliferative Potential Colony-Forming Unit Granulocyte-Monocytes: Validation of Cell Processing

Abstract

BackgroundThe material for transplantation must be of the highest quality. As far as we know, short-term storage is one of the crucial points of stem cell banking. According to the quality assurance system in a stem cell bank, each step of cell processing must be validated. The aim of this study was to assess the influence of short-term storage conditions into a clonogenic assay. MethodsMaterial was collected from mobilized peripheral blood by means of leukapheresis from 15 patients. Samples were stored at 4°C and 20°C; samples were evaluated on the day of leukapheresis and after 24 hours and after 48 hours of storage. The number of colony-forming unit granulocyte-monocyte (CFU-GM) precursors was analyzed with the use of in vitro culture. The material was evaluated before freezing and after thawing. ResultsThe average number of CFU-GM precursors in the material stored at 4°C before freezing on the day of collection was 84/105 nuclear cells (nc) and after 24 hours and 48 hours of storage was, respectively, 62/105 nc (P = .011719) and 36/105 nc (P = .02088). The average of the CFU-GM precursors in material stored at 20°C after 24 hours and 48 hours of storage amounted to 33/105 nc (P = .004439) and 2/105 nc (P = .00346), respectively. ConclusionsIn our study, the number of colonies of CFU-GM after 24 hours and 48 hours of storage, both at 4°C and 20°C, was significantly reduced compared with the number of colonies on the day of collection. Significantly greater numbers of CFU-GM precursors were observed in the material stored before freezing at 4°C in comparison with the material stored at 20°C.