Umbilical-cord blood (UCB) is increasingly considered as an alternative to peripheral
blood progenitor cells (PBPCs) or bone marrow, especially when an HLA-matched adult
unrelated donor is not available. We aimed to determine the optimal role of UCB grafts
in transplantation for adults with acute leukaemia, and to establish whether current
graft-selection practices are appropriate.
We used Cox regression to retrospectively compare leukaemia-free survival and other
outcomes for UCB, PBPC, and bone marrow transplantation in patients aged 16 years
or over who underwent a transplant for acute leukaemia. Data were available on 1525
patients transplanted between 2002 and 2006. 165 received UCB, 888 received PBPCs,
and 472 received bone marrow. UCB units were matched at HLA-A and HLA-B at antigen
level, and HLA-DRB1 at allele level (n=10), or mismatched at one (n=40) or two (n=115)
antigens. PBPCs and bone-marrow grafts from unrelated adult donors were matched for
allele-level HLA-A, HLA-B, HLA-C, and HLA-DRB1 (n=632 and n=332, respectively), or
mismatched at one locus (n=256 and n=140, respectively).
Leukaemia-free survival in patients after UCB transplantation was comparable with
that after 8/8 and 7/8 allele-matched PBPC or bone-marrow transplantation. However,
transplant-related mortality was higher after UCB transplantation than after 8/8 allele-matched
PBPC recipients (HR 1.62, 95% CI 1.18-2.23; p=0.003) or bone-marrow transplantation
(HR 1.69, 95% CI 1.19-2.39; p=0.003). Grades 2-4 acute and chronic graft-versus-host
disease (GvHD) were lower in UCB recipients compared with allele-matched PBPC (HR
0.57, 95% 0.42-0.77; p=0.002 and HR 0.38, 0.27-0.53; p=0.003, respectively), while
the incidence of chronic, but not acute GvHD, was lower after UCB than after 8/8 allele-matched
bone-marrow transplantation (HR 0.63, 0.44-0.90; p=0.01).
These data support the use of UCB for adults with acute leukaemia when there is no
HLA-matched unrelated adult donor available, and when a transplant is needed urgently.
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