Exercise-Mobilized Donor Lymphocyte Infusions (Dli-X) for the Prevention and Treatment of Leukemic Relapse After Allogeneic Hematopoietic Cell Transplantation

Abstract

Donor lymphocyte infusion (DLI) remains a cornerstone immunotherapeutic strategy for preventing and treating leukemic relapse following allogeneic hematopoietic cell transplantation (alloHCT), particularly in patients with high-risk myeloid malignancies such as acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and myelodysplastic syndromes (MDS). Despite its clinical utility, the efficacy of DLI is often limited, and it carries the risk of life-threatening graft-versus-host disease (GvHD), necessitating the urgent development of strategies to enhance graft-versus-leukemia (GvL) effects while mitigating GvHD risks. Our lab and others have demonstrated that a single bout of acute exercise elicits a rapid mobilization of effector lymphocytes triggered by catecholamine release and β2-adrenergic dependent signaling. This mobilization significantly enriches the peripheral blood with GvL favoring subsets, including natural killer (NK) cells, CD8+ T cells, and γδ T cells, while concurrently reducing the frequency of naïve CD4+ T cells implicated in GvHD. Preclinical studies further support that these exercise-mobilized lymphocytes exert enhanced antileukemic effects in xenogeneic mouse models while displaying transcriptomic signatures consistent with enhanced anti-tumor activity and cytokine responsiveness.These data support the idea that exercise-mobilized donor lymphocyte infusions ‘DLI-X’ can be used as a simple and economical strategy to augment GvL effects to prevent and treat leukemic relapse after alloHCT. Notably, we introduce the novel approach of triple cytokine (IL-12, IL-15, IL-18) stimulation in whole PBMCs, which has previously only been used with purified NK and γδ T cells, to enhance the efficacy of DLI further. Given the enrichment of CD8+, γδ T cells, and NK cells in DLI-X, we hypothesize that overnight stimulation with triple cytokines will further enhance the potency of the graft ‘DLI-XS’. Herein, we show that DLI-XS is a superior product in vitro against leukemia cell lines K562, HL-60, and TF1. Meanwhile, DLI-X improves outcomes in vitro against all target cell lines and in vivo against K562. These novel findings present a feasible, scalable, and clinically promising strategy to improve DLI efficacy.