Comparison of in vitro growth characteristics of blast cell progenitors
(CFU-L) in patients with myelodysplastic syndromes and acute myeloid
leukemia
C Aul, N Gattermann and W Schneider
Department of Internal Medicine, Heinrich Heine University, Dusseldorf,
Germany.
Current knowledge is inadequate to explain the different patterns of blast
cell accumulation in myelodysplastic syndromes (MDS) and acute myeloid
leukemia (AML). We compared the growth patterns of blast cell progenitors
(CFU-L) in 23 patients with advanced MDS and 32 patients with de novo AML.
Circulating blast progenitors were identified in 74% of MDS and 81% of AML
samples. Primary plating efficiencies (PE1) were similar in both disorders,
despite marked differences in peripheral blast cell concentrations. By
cytological and cytochemical examination, colonies from MDS patients were
indistinguishable from those obtained in AML. Cell cycle status was
assessed by loss of colony formation following short-term exposure to
cytosine arabinoside. CFU-L suicide rates (median, range) were 40% (12% to
77%) in MDS and 60.5% (27% to 98%) in AML. Actively proliferating blast
cell progenitors are thus not confined to AML, but are also present in the
majority of MDS patients. An important difference between MDS and AML was
found when self-renewal capacity of CFU-L was examined by means of
secondary plating efficiencies (PE2). Colonies could be successfully
replated in 74% of AML cases. PE2 showed marked heterogeneity (2 to 730
colonies/10(5) mononuclear cells), with some values indicating excessive
self-renewal capacity of CFU-L. In contrast, 62% of the MDS specimens
failed to produce any secondary colony growth, and PE2 in the remaining
cases was low (5 to 99/10(5) MNC). We conclude that a different balance
between self-renewal and determination could be responsible for a slower
pace of clonal expansion in MDS, even if the proliferative activity of
clonogenic cells is similar to that in AML.
Volume 80,
Issue 3,
pp. 625-633,
08/01/1992
Copyright © 1992 by The American Society of Hematology