graftversustumor

Graftversustumor, usually referred to as the graft-versus-tumor (GVT) effect, denotes the anti-tumor immune response that donor immune cells can mount after an allogeneic hematopoietic stem cell transplant. It contributes to the control of residual malignant cells and lowers relapse risk in several hematologic cancers, most notably acute myeloid leukemia, acute lymphoblastic leukemia, and some myelodysplastic syndromes.

Mechanism and scope: The effect arises when donor T lymphocytes recognize leukemia-associated antigens presented by malignant cells or by host antigen-presenting cells. Activated donor immune cells can directly kill tumor cells and recruit other immune mechanisms. Natural killer cells may also participate. GVT is often linked to graft-versus-host disease (GVHD), a related but distinct phenomenon, with stronger donor immune reactivity tending to increase both GVT and GVHD.

Clinical implications: GVT is a desirable component of transplant success, but its magnitude varies by disease, transplant type, and degree of immune mismatch. Clinicians strive to balance maximizing GVT to suppress relapse while minimizing GVHD-related morbidity. In some cases of relapse, interventions aim to boost GVT, whereas in others GVHD risk limits such strategies.

Diagnosis and management: There is no single diagnostic test for GVT. Its impact is inferred from disease control, relapse rates, and immune monitoring. Management strategies include donor lymphocyte infusions to enhance GVT in relapse, along with approaches to control GVHD. Experimental strategies continue to explore targeted ways to augment GVT while limiting toxicity.

Prognosis and research: GVT can meaningfully improve disease control after transplantation, but its usefulness depends on patient- and disease-specific factors. Ongoing research seeks ways to selectively enhance GVT, including immune-based therapies and better patient-tailored regimens.