Annals of Medicine, 11 February 2026
A 10-year retrospective study conducted by Chinese scientists has demonstrated that adding umbilical cord blood transfusion to unrelated donor haematopoietic stem cell transplantation (URD-cord-HSCT) optimizes survival rates and thoroughly resolves dangerous complications in patients with aplastic anaemia.
- Clinical Challenges and Dilemmas in Bone Marrow Transplantation
For patients under 40 years old suffering from severe aplastic anaemia (SAA) or transfusion-dependent non-severe aplastic anaemia (TD-NSAA), matched sibling donor haematopoietic stem cell transplantation (MSD-HSCT) remains the gold standard, offering a remarkably high 10-year overall survival rate.
However, the greatest barrier is that fewer than 30% of patients can find a suitable matched sibling donor within their family (particularly in countries with a historical one-child policy, such as China). When forced to switch to alternative donor sources, clinicians face distinct limitations:
- Unrelated Donors (URDs): Often limited by elevated rates of mixed chimerism (MC), susceptibility to graft failure (GF), and severe graft-versus-host disease (GVHD).
- Haploidentical Donors (Haplo): Although readily available within the family, this approach carries a risk of poor graft function post-transplantation.
To find an optimal solution for patients lacking a matched sibling donor, physicians at the First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Integrated Traditional Chinese and Western Medicine) trialled a novel technique: combining unrelated donor transplantation (URD-HSCT) with co-transfusion of umbilical cord blood (UCB).
- Study Design
The study involved a retrospective analysis of patients treated between January 2014 and December 2023. All patients received a standardized fludarabine, cyclophosphamide, and rabbit anti-thymocyte globulin (FCA)-based conditioning regimen prior to transplantation.
A total of 104 patients were enrolled and allocated into three baseline-matched cohorts at a 1:1:2 ratio (matched for age, sex, and disease status):
- URD-cord-HSCT Group (n = 26): Received haematopoietic stem cell transplantation from an unrelated donor combined with umbilical cord blood transfusion (utilizing bone marrow and peripheral blood stem cells, supplemented with cord blood).
- MSD-HSCT Group (n = 26): Received transplantation from a fully HLA-matched sibling donor (utilizing bone marrow and peripheral blood stem cells only).
- Haplo-HSCT Group (n = 52): Received transplantation from a haploidentical donor (utilizing bone marrow and peripheral blood stem cells only).
- Detailed Clinical Outcomes After a 3-Year Follow-up
Following a 3-year follow-up period, this combination strategy yielded highly promising clinical data:
- Absolute Survival Rates: Patients who underwent fully HLA-matched unrelated donor transplantation supplemented with cord blood (MUD-cord-HSCT) achieved a 3-year overall survival (OS) rate of 100% and an event-free survival (EFS) rate of 85.7%. These outcomes significantly outperformed those of the haploidentical transplantation (Haplo-HSCT) group.
- Eradication of Mixed Chimerism (MC): The cumulative incidence of MC in the cord blood-supplemented group dropped to 0%, which was significantly lower than that observed in the matched sibling donor group (24.48%).
- Safety Profile Regarding GVHD: The addition of umbilical cord blood minimized the incidence of severe grade II–IV acute graft-versus-host disease (GVHD) compared to transplant methods using mismatched donors.
- Biological Mechanisms and Practical Significance
Scientists attribute the success of this combination method to the unique biological properties of umbilical cord blood (UCB):
- Enhancing Engraftment: Cells within the cord blood facilitate the homing and proliferation of the unrelated donor’s stem cells within the recipient’s bone marrow microenvironment.
- Immunomodulation: Cord blood is rich in naive T cells, which attenuate hyperactive immune responses. This effectively eradicates mixed chimerism and minimizes life-threatening GVHD complications.
Conclusion: The study confirms that MUD-cord-HSCT serves as a preferable and highly safe alternative strategy for patients with severe aplastic anaemia when lacking a matched sibling donor. It not only delivers an absolute survival rate (100% in this cohort) but also provides an optimal solution to the two greatest hurdles in transplantation medicine: mixed chimerism and graft-versus-host disease.
References
Hu, T., Jia, X., Xin, C., Shen, Y., Liu, Q., Hong, Y., … & Wu, D. (2026). Cord blood transfusion added matched unrelated donor transplantation as a preferable choice for aplastic anaemia: a comparative study from a single centre. Annals of Medicine, 58(1), 2635832.
Source: Annals of Medicine
Link: https://doi.org/10.1080/07853890.2026.2635832
