autologous blood and marrow transplantation - Blog Science ...

Autologous vs. Unrelated Allogeneic
Bone Marrow Transplantation (AlloBMT)
for Acute Lymphoblastic Leukemia (ALL)
Michael W. Boyer, Andrew M. Yeager
Emory University School of Medicine, Atlanta, GA
ABSTRACT
The treatment of choice in patients with high-risk acute lymphoblastic leukemia
(ALL) is allogeneic bone marrow transplantation (alloBMT) from an HLAmatched
sibling donor (MSD). The event-free survival after MSD BMT for ALL
ranges from 30 to 65% and depends on the disease status of the patient. Relapse
remains the major cause of failure of MSD BMT for ALL. The presence of acute
graft-vs.-host disease (GVHD) greatly influences post-BMT relapse; in MSD BMT
for first-remission ALL, the risk of relapse is decreased by a factor of 2.77 in
patients with acute GVHD compared with those without GVHD. However, the
graft-vs.-leukemia (GVL) benefit of acute GVHD does not always translate into
improved event-free survival after MSD BMT because of GVHD-related mortality.
Since most patients with high-risk ALL lack MSDs, alternative hematopoietic cell
transplants have been explored. Autologous BMT (autoBMT) with marrow
harvested in remission and usually treated ex vivo (e.g., with monoclonal
antibodies) is generally well tolerated but is associated with high relapse rates in
most series. A comparison of autoBMT and allogeneic MSD BMT for high risk
ALL showed no statistically significant difference in event-free survival but
substantial differences in relapse rates: 79% in autoBMT, 75% in MSD BMT with
no GVHD, and only 37% in MSD BMT with GVHD. Quantitative analysis of
clonogenic ALL cell content in the harvested marrow of autoBMT recipients
suggests that, as with alloBMT for ALL, the failure to eradicate residual leukemia
in vivo is the biggest obstacle to improving event-free survival after autoBMT for
ALL. BMT from volunteer unrelated donors (UDs) is another alternative in highrisk
ALL. Event-free survival after UD BMT for ALL ranges from 12 to 43%;
these results are comparable to autoBMT in patients with first-remission ALL and
superior to autoBMT in patients beyond first remission. In UD BMT, the major
cause of failure is a high rate (50 to 70%) of transplant-related mortality. In
contrast, the relapse rate after UD BMT for ALL is relatively low; after oneantigen-mismatched
UD BMT, the relapse rate is 38% of that observed after MSD
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