Influence of time-of-day of graft infusion on allogeneic hematopoietic stem cell transplantation outcomes

SUMMARY

The biological clock plays a central role in hematopoiesis and immune regulation, making circadian rhythms an increasingly important factor in immunotherapies and cellular therapies such as allogeneic hematopoietic stem cell transplantation (allo-HSCT). Previous work by Hou et al suggested that afternoon graft infusions were associated with a higher risk of acute graft-versus-host disease and worse survival, highlighting a potential role for infusion timing in shaping transplant outcomes. To further investigate this, the authors of this article performed a retrospective analysis of 368 patients who underwent allo-HSCT at Geneva University Hospitals between 2015 and 2024. Observing that infusion timing patterns at their center differed from those reported by Hou et al, they applied a data-driven approach using receiver operating characteristic analysis, which identified 11:17 as the optimal cut-off for overall survival. Stratification using this threshold revealed that patients receiving grafts before 11:00 had significantly improved 2-year overall survival and lower non-relapse mortality compared with those infused later in the day, with no differences in relapse or engraftment rates. These findings suggest that infusion timing may be an important, under-recognised factor influencing allo-HSCT outcomes. Prospective clinical trials are needed to confirm these observations and explore their applicability across different clinical contexts.

Full article: https://doi.org/10.1136/jitc-2025-013372

WHY IS THIS IMPORTANT?

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can cure serious blood diseases but still carries a high risk of complications and death. This study shows that when stem cells are infused during the day may influence patient survival. By analysing 368 patients, researchers found that those who received their transplant before 11:00 a.m. had better 2-year survival and fewer deaths unrelated to disease relapse, compared with those treated later. This difference was not explained by relapse or delayed recovery of blood cells. The findings suggest that the body’s biological clock affects how the immune system responds to transplantation. If confirmed, adjusting transplant timing could become a simple, low-cost way to improve outcomes for many patients worldwide.

Funding: This work was supported by grants from the Geneva Cancer League.

Citation: Bernardi C, Pradier A, Masouridi-Levrat S, Morin S, Mamez A, Giannotti F, et al. Influence of time-of-day of graft infusion on allogeneic hematopoietic stem cell transplantation outcomes: a validation cohort study. Journal for ImmunoTherapy of Cancer. 2025;13:e013372. https://doi.org/10.1136/jitc-2025-013372

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