Viability and functional capacity after thawing of hematopoietic progenitor cells cryopreserved at a cord blood stem cell bank in Colombia

ObjectiveTo evaluate the viability and functional capacity of hematopoietic progenitor cells from cord blood samples cryopreserved at the Banco de Células Stem de Colombia.MethodsAfter thawing and centrifugation of 20 samples, viable white blood cells were numbered by the trypan blue method and CD34+CD45+ dim hematopoietic progenitor cells were numbered by flow cytometry. Clonogenic assays also tested the functional capacity of viable CD34+CD45+ dim cells.ResultsThe median rates of viable CD34+CD45+ dim cells were 99.6% before freezing and 73.0% after thawing (P < 0.001). The 20 cultures yielded a median of 12 cells with a lineage of red cells, 17.5 cells with a lineage of white cells, and 10 cells with a mixed lineage.ConclusionAlthough the rate of viable CD34+CD45+ dim cells was decreased by 26.6% after thawing by the method we used, the numbers of CD34+CD45+ dim cells that formed colonies were similar to those obtained by other published methods.