Clinical-scale elutriation as a means of enriching antigen-presenting cells and manipulating alloreactivity.

BACKGROUND AIMS: Clinical-scale elutriation using the Elutra(c) has been shown to enrich monocytes reliably for immunotherapy protocols. Until now, a detailed assessment of the four (F1-F4) non-monocyte fractions derived from this process has not been performed. METHODS: Using fluorescence-activated cell sorting (FACS), we performed phenotypic analyses to investigate the possible enrichment of T, B, natural killer (NK) and dendritic cells (DC) or their subsets in one or more Elutra fractions. RESULTS: Blood DC were enriched up to 10-fold in some fractions (F3 and F4) compared with the pre-elutriation apheresis product. This increased the number of DC that could be isolated from a given cell number by immunomagnetic separation. It was also found that CD62L(-) effector memory CD4(+) T cells were enriched in later fractions. In four of five cases tested, cells from F3 demonstrated decreased alloreactive proliferation in a mixed lymphocyte reaction compared with cells from the apheresis product. B cells were enriched in F1 compared with the apheresis product. CONCLUSIONS: In addition to providing enrichment of monocytes for the generation of DC, the Elutra enriches cell subsets that may be incorporated into and enhance existing immunotherapy and stem cell transplantation protocols.