Impact of collection programs for the generation of monocyte apheresis products on product quality and composition as starting material for the generation of cellular therapeutics.

BACKGROUNDWith the discontinuation of the last generation of apheresis machines, new options for monocyte apheresis became available. As apheresis products play a crucial role in the generation of new cellular therapeutics (e.g., generation of dendritic cells [DCs] or precursor for T-cell experiments) we sought to compare two different collection programs for potential benefits or disadvantages due to different composition of the cellular products. STUDY DESIGN AND METHODSComposition of discontinuously and continuously collected monocyte products from the same 13 donors was analyzed. For further evaluation as starting material for manufacturing of cellular therapeutics typically used steps such as Ficoll Isopaque, cryoconservation and monocyte isolation, with subsequent generation of mature DCs (mDCs) and assessment of T-cell function, were performed on seven of these apheresis pairs. RESULTSYield of total cells, monocytes, and mDCs was equal with both methods. T-cell composition did not differ significantly in content of CD3+, CD4+, and CD8+cells. Differentiation status and cytokine production of CD8+T cells upon stimulation with cytomegalovirus pp65 antigen was not significantly different. CONCLUSIONBoth methods seem comparably suited for the generation of cellular products. If the intended use is fresh (without cryoconservation), continuously harvested cells show better cell numbers, while discontinuously harvested cells show better recovery after cryoconservation.