Cord blood transfusion added matched unrelated donor transplantation as a preferable choice for aplastic anaemia: a...

Matched sibling donors (MSDs) were preferred for haematopoietic stem cell transplantation (HSCT) in severe aplastic anaemia (AA) when lacking MSDs, unrelated donors (URDs) and haploidentical (Haplo) donor would be considered, but limited by increased graft-versus-host disease (GVHD) and recommended only in experienced centres. This study aimed to compare the efficacy and safety of umbilical cord blood transfusion added URD-HSCT (URD-cord-HSCT) to MSD-HSCT and Haplo-HSCT in AA patients.

Patients who underwent URD-cord-HSCT (n = 26), MSD-HSCT (n = 26) or Haplo-HSCT (n = 52) were retrospectively enrolled at 1:1:2 ratio between January 2014 and December 2023. Clinical characteristics, treatment responses and survival outcomes were evaluated.

No significant differences in neutrophil and platelet engraftment. The three-year overall survival (OS) rates were 88.0% ± 6.5%, 92.1% ± 5.3% and 74.8% ± 6.0% (p = .10), and the event-free survival (EFS) rates were 77.3% ± 9.4%, 92.1% ± 5.3% and 69.0% ± 6.4% (p = .13) in URD-cord-HSCT, MSD-HSCT and Haplo-HSCT groups, respectively. Fully HLA-matched URD-cord-HSCT (MUD-cord-HSCT) demonstrated superior OS (100%) and EFS (85.7% ± 13.2%) compared to Haplo-HSCT (p = .046, p = .049) and single HLA allele-mismatched URD-cord-HSCT (MMUD-cord-HSCT, p = .04, p = .04). The incidence of mixed chimerism (MC) was significantly lower in the URD-cord-HSCT group compared to the MSD-HSCT group (0% vs. 24.48%, p = .01). MUD-cord-HSCT experiences lower grade II-IV acute GVHD comparing with MMUD-cord-HSCT (p = .02) and Haplo-HSCT (p = .048).

MUD-cord-HSCT provides an optimal solution for MC and GVHD, with outcome comparable or even better than those of MSD-HSCT.KEY MESSAGESThe best choice of alternative donor for aplastic anaemia remains a clinical challenge, unrelated donors (URDs) or haploidentical (Haplo) donor?Umbilical cord blood (UCB) transfusion added matched unrelated donor (MUD) haematopoietic stem cell transplantation (HSCT) exert nearly 0% cumulative incidence of mixed chimerism and grade II-IV acute/chronic GVHD;UCB added MUD-HSCT (MUD-cord-HSCT), which exert 100% three-year overall survival (OS) and 85.7% event free survival (EFS), rather than matched sibling donor (MSD)-HSCT, exert superiority in OS and EFS than mismatched URD (MMUD)-HSCT and haploidentical-HSCT.MUD-cord-HSCT provides an optimal solution for MC and GVHD, with outcome comparable or even better than those of MSD-HSCT.