Abstract
Background
T- and B-cell depletion of apheresis products is an attractive alternative to standard stem cell enrichment in haplo-identical transplantation. Thorough T- and B-cell depletion is necessary for prevention of acute GvHD and T-cell depletion-associated lymphoproliferative disorders. However, the large number of non-T and -B cells in the graft requires special protocols for the determination of extremely low frequencies of residual T cells.
Methods
Apheresis products from healthy donors were T- and B-cell depleted by the CliniMACS™ system using CD3 and CD19 Ab reagents and the LS tubing set. The recovery of cells and degree of depletion were determined. A four-color multigating strategy was used for enumeration of residual T and B cells
Results
One-hundred and three separations were performed, with a mean cell recovery of 38±12%, CD34 recovery of 61±16% and CD56 recovery of 63±33%. T and B cells were depleted by log 4.15±0.46 and log 3.64±0.63, respectively. Four-color multigating flow cytometry allowed the detection of single T cells.
Discussion
Combined T- and B-cell depletion is a feasible method for obtaining stem cell grafts with acceptable stem cell recovery, profound T- and B-cell depletion and a very high amount of NK cells and monocytes. However, analysis of residual T cells is challenging and requires special protocols.