# 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

## TL;DR

This paper reviews how T cells and natural killer cells work together in a type of stem cell transplant for treating acute myeloid leukemia, highlighting their roles in immune responses and future treatment strategies.

## Contribution

The paper systematically integrates the cooperative immunological interactions between T cells and NK cells in allogeneic stem cell transplantation for AML.

## Key findings

- T cells and NK cells synergistically contribute to immune reconstitution and graft-versus-leukaemia responses.
- Early NK-cell recovery supports T-cell function restoration, while T-cell-derived cytokines enhance NK-cell activity.
- Understanding T-NK cell interactions can guide the development of more effective post-transplant immunotherapies.

## Abstract

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.

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.

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.

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.