Ex vivo Expansion of Highly Purified NK Cells for Immunotherapy after Haploidentical Stem Cell Transplantation in Children

Abstract

Clinical scale enrichment and activation of allogeneic donor NK cells is feasible. High dose NK cell application may be a new treatment option for pediatric patients with leukemia or solid tumors in case of minimal residual disease or unbalanced chimerism post haplo-SCT as we could show for the first three patients .

Pre-emptive immunotherapy with purified natural killer cells after haploidentical SCT: a prospective phase II study in two centers

“…26,27 Some single-center experiences showed a benefit of IL-2-stimulated NK cells compared with freshly isolated, resting NK cells with regard to the cytotoxicity against leukemic and tumor targets. 18,[28][29][30][31] This was due to a strong upregulation of the activating receptors NKp30, NKp44, NKp46 and NKG2D during IL-2 stimulation. 18 Further investigations might improve on this by activation with additional cytokines like IL-15, IL-18 or IL-21.…”

“…18,[28][29][30][31] This was due to a strong upregulation of the activating receptors NKp30, NKp44, NKp46 and NKG2D during IL-2 stimulation. 18 Further investigations might improve on this by activation with additional cytokines like IL-15, IL-18 or IL-21. 28,[32][33][34] Nevertheless those strategies require close patient monitoring to investigate the influence of the respective cytokine on the cell sub-population in peripheral blood.…”

“…The two-step ex vivo purification procedure (CliniMACS cell selection system) included CD3 depletion followed by a CD56-positive selection. 16,18,19 At each step, cells were analyzed for percentage and viable absolute number of CD56 þ CD3 À , CD3 þ and by flow cytometry in single and dual platform approaches as described previously. 20,21 In case of a contaminating T-cell dose of X1.0 and o2.0 Â 10 5 /kg, the processed NK product was split into two units.…”

Clinical-scale generation of human anti-Aspergillus T cells for adoptive immunotherapy

“…In this respect, our protocol allows the prophylactic preparation of antiAspergillus T cells, as the yield after thawing of cryopreserved T cells was similar to those of other primary human cells, and, more importantly, as cryopreservation did not affect the functional activity of the generated cells. 22 Although we did not assess the capacity to damage hyphae of A. fumigatus, the CD4 þ T cells generated according to GMP conditions produced IFN-g upon restimulation with Aspergillus antigens, and thus most likely enhance the antifungal activity of phagocytes. 10 Our in vitro data also indicate a reduced alloreactivity of the generated antiAspergillus T cells and support the in vivo findings by Perruccio et al 16 who transferred ex vivo cultured and pathogen-specific T cells without triggering GVHD.…”

Haploidentical SCT in children: an update and future perspectives

“…Further efforts are warranted to improve the results in patients with high leukemia burden. Ongoing pilot studies address the use of new drugs such as clofarabine (which can induce remissions in otherwise refractory disease) as part of the conditioning regimen and post-transplant immunotherapies, such as administration of cytokines in vivo and infusion of donor-derived effector cells (alloreactive NK cells 55 or T cells) with antileukemic potential. The role of MSC for treatment of GVHD and facilitation of engraftment is under investigation.…”