T regulatory cell separation for clinical application

We selected T regulatory cells (Tregs) from standard leukapheresis using double-negative selection (anti-CD8 and anti-CD19) followed by positive selection (anti-CD25) and 72 procedures were performed. A median of 263 × 106 cells (range 143–470 × 106) were recovered with a mean of CD4+/CD25+ cells of 94.5 ± 2.4% (36.5 ± 18.6% CD4+/CD25+hi). FoxP3+ cells were equal to 79.8% ± 22.2. CD127+ cells were 12.5% ± 8.2. The inhibition assay showed an inhibition rate of 67 ± 22. Cells isolated by means of this approach can be used in allogeneic hematopoietic stem cell transplantation to reduce the incidence and severity of GvHD without bystander inhibition of general immunity.