| Abstract: | Density gradient centrifugation has been used in animal systems to purify stem cells and eliminate T lymphocytes prior to allogeneic transplantation. There is substantial disagreement whether the same approach can be used to purify hematopoietic stem cells obtained from human peripheral blood. The purpose of the present study was to resolve that issue by determining the density distribution of 4 classes of human leucocytes: total mononuclear cells, T lymphocytes, CFUc, and BFUe. To ensure a representative sampling, a large number of randomly selected donors were analyzed. The results show that most T lymphocytes band between 1.068 and 1.071 g/ml, with relatively little variation from individual to individual. In contrast, the density distributions of both CFUc and BFUe fluctuated markedly from donor to donor. As a consequence, there was significant variability in the degree of progenitor-T cell separation. The implications of these results for clinical application of the density separation technique are discussed. |
