Synergistic immune interactions between T cells and natural killer cells in allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia: current status and future directions

BACKGROUND: Acute myeloid leukaemia (AML) is a highly heterogeneous haematologic malignancy. Current therapeutic strategies include chemotherapy, targeted therapy and haematopoietic cell transplantation (allo-HSCT) and autologous haematopoietic cell transplantation (auto-HSCT). The graft-versus-leukaemia (GVL) effect and graft-versus-host disease (GVHD) in allo-HSCT remain major research foci, with emerging evidence highlighting the synergistic roles of T cells and natural killer (NK) cells in allo-HSCT immunity. This review systematically integrates the cooperative immunological interactions between T cells and NK cells and elucidates their critical significance in post-transplant immunotherapy. METHODS: This review systematically summarizes the cytotoxic mechanisms, immune reconstitution processes and related immunotherapeutic approaches involving T cells and NK cells in AML in the context of allo-HSCT and further elucidates their unique role in post-transplant immune regulation from the perspective of coordinated T-cell and NK-cell interactions. RESULTS: T cells and NK cells exert synergistic effects in post-transplant immune reconstitution, GVL responses, GVHD regulation and subsequent immunotherapeutic interventions. Early NK-cell reconstitution provides a critical window for the restoration of T-cell function, whereas cytokines derived from T cells, such as IL-2 and IL-15, further enhance NK-cell activity. This dynamic immunological interplay not only shapes the balance between GVL and GVHD, but also informs the development of post-transplant immunotherapeutic strategies. CONCLUSION: The dynamic interplay between T cells and NK cells plays a pivotal role in allo-HSCT for AML. This review systematically integrates the cooperative functions of T cells and NK cells within the allo-HSCT immune landscape, offering new perspectives for advancing post-transplant immunotherapy. A deeper understanding of these mechanisms is expected to provide a theoretical foundation for optimizing post-transplant immune interventions in AML patients and for developing more precise therapeutic strategies.