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

Abstract

Background aims: The 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.

Methods: Investigators performed 102 separations. Apheresis products with a median 5.8 (minimum to maximum, 1.2-10.4) × 10(10) mononuclear cells were used with a median 358 (92-1432) × 10(6) 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.

Results: After 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).

Conclusions: Profound 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 × 10(6) CD34(+) cells/kg can be performed for every patient with 1-5 × 10(4) TCRαβ(+) cells/kg and about 5-10 × 10(6) TCRγδ(+) cells/kg with two rounds of apheresis.

Keywords: B cell; CliniMACS; T cell; allogeneic transplantation; depletion; flow cytometry.