Depletion of T-cell receptor alpha/beta and CD19 positive cells from apheresis products with the CliniMACS device

Background aimsThe CliniMACS device (Miltenyi Biotec, Bergisch Gladbach, Germany) was used for depletion of T-cell receptor alpha/beta positive (TCRαβ+) and CD19 positive (CD19+) cells from apheresis products.MethodsInvestigators performed 102 separations. Apheresis products with a median 5.8 (minimum to maximum, 1.2–10.4) × 1010 mononuclear cells were used with a median 358 (92–1432) × 106 CD34+ cells. There were 24.8% (6.1–45.7%) median TCRαβ+ cells and 4.4% (1.2–11.7%) median B cells in the apheresis product.ResultsAfter depletion, a median 0.00097% (0.00025–0.0048%) of TCRαβ+ cells could be detected, and B cells, as determined as CD20+ cells, were reduced to 0.0072% (0.0008–0.072%). TCRαβ+ cells were depleted by log 4.7 (3.8–5.5), and B cells were depleted by log 4.1 (3.0–4.7). Recovery of mononuclear cells was 55% (33–77%), and recovery of CD34+ cells was 73% (43–98%). Recovery of CD56+/3− natural killer cells was 80% (35–142%), recovery of TCR gamma/delta positive (TCRγδ+) T cells was 83% (39–173%) and recovery of CD14+ cells was 79% (22–141%). Viability of cells was 98% (93–99%) after separation (all values median).ConclusionsProfound depletion of TCRαβ+ T cells can be achieved with the CliniMACS system. Recovery of CD34+ stem cells is in the same range than after CD34+ enrichment and CD3/CD19 depletion. Transplantation with >4 × 106 CD34+ cells/kg can be performed for every patient with 1–5 × 104 TCRαβ+ cells/kg and about 5–10 × 106 TCRγδ+ cells/kg with two rounds of apheresis.