Allogeneic HLA-Matched Donor Dendritic Cells Loaded with Patient Leukemic Blasts Preferentially Induce CD4-Positive Leukemia-Reactive Donor Lymphocytes

Abstract

Background: The therapeutic value of donor lymphocyte infusions in patients who relapse with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT) is limited by a low efficacy and the risk of graft-versus-host disease. We aimed at generating leukemia-reactive donor T cells for patients with AML. Methods: Peripheral blood mononuclear cells of the donor were stimulated with mature donor dendritic cells, pulsed with irradiated patient leukemic blasts (LB), or directly with cytokine-treated LB. After 3 weekly stimulations, donor cells were tested for anti-leukemic reactivity in an IFNγ Elispot. Results: In 5 of 6 donors, cells with reactivity against patient LB with low or absent reactivity against non-leukemic cells could be generated. T cell subset analyses in 2 donors indicated that specific anti-leukemic reactivity was mainly mediated by CD4+ T cells, which were also the predominant cell fraction in 4 of 6 donors. One leukemia-reactive donor T cell line was expanded with a recently developed system. One week of expansion resulted in a 10-fold increase in reactivity with sustained specificity of the resulting T cell line. Conclusions: Our results show the feasibility of the in vitro generation of leukemia-reactive donor lymphocytes, rendering this method a promising tool for post-HSCT immunotherapy.

Dendritic Cell Maturation With Poly(I:C)-based Versus PGE2-based Cytokine Combinations Results in Differential Functional Characteristics Relevant to Clinical Application

“…To mimic CD40L-mediated T-cell help in the lymph node, 23 we also stimulated mature DCs with CD40L-transfected K562 cells. 24 We focused on global transcriptional and on molecular and phenotypic features of the resulting DCs to generate portraits of differential DC maturation. Specifically, we sought to test the hypothesis that a poly(I:C)-based cocktail would induce a stronger T helper (T H ) 1 cytokine milieu characterized by high secretion of IL-12p70 without an impairment in phenotypical maturity, lymph node homing capacity, or immunostimulatory properties through expression of IDO and IL-10.…”

A simple two‐step culture system for the large‐scale generation of mature and functional dendritic cells from umbilical cord blood CD34+ cells

“…Neves and workers 33 reported that they are even better than autologous DCs, especially in cases when the autologous DCs are functionally impaired. DCs generated from HLA‐matched or partially mismatched donors have also shown to induce clinical response 34‐36 . In such circumstances UCB CD34+‐derived DCs will be an attractive source for HLA‐matched or partial mismatched allogeneic DCs.…”