Impact of Donor Characteristics on the Outcomes Following Haploidentical Haematopoietic Stem Cell Transplantation in Patients Aged 55 Yr and Older.

Haploidentical haematopoietic stem cell transplantation (haplo-HSCT) provides curative potential for older patients with haematological malignancies. Since multiple haploidentical donors may be available for a given patient, identifying factors that influence transplant outcomes, particularly donor-related characteristics, is critical. This study aimed to identify donor factors that are associated with transplant outcomes, particularly focusing on the impact of donor age on overall survival (OS), disease-free survival (DFS), and transplant-related mortality (TRM) in patients aged ≥55 yr undergoing haplo-HSCT. This retrospective study included 460 patients aged ≥55 yr with acute leukaemia or myelodysplastic syndromes who underwent haplo-HSCT. Multivariate analysis was used to assess the association between donor factors and transplant outcomes, with subgroup comparisons for younger (<33 yr) versus older (≥33 yr) donors. Multivariate analysis showed that increasing donor age was significantly associated with inferior OS (HR 1.22, 95% CI: 1.10 to 1.36; P < .001), poorer DFS (HR 1.20, 95% CI: 1.09 to 1.32; P < .001), and higher TRM (HR 1.20, 95% CI: 1.07 to 1.34; P = .001). Compared with donors aged ≥33 yr, younger donors (<33 yr) were associated with better OS (80.8% versus 67.6%, P = .002), improved DFS (73.8% versus 62.6%, P = .002), and lower TRM (16.6% versus 24.2%, P = .03). This study indicated that donor age significantly influences the outcomes of haplo-HSCT in patients ≥55 yr. Younger donors, particularly those aged <33 yr, were associated with better OS and DFS and lower TRM, suggesting that younger donors may be preferred for older patients undergoing haplo-HSCT.