Acidic isoferritins (leukemia-associated inhibitory activity) fail to
inhibit blast proliferation in acute myelogenous leukemia
R Taetle
Cell-free extracts of bone marrow and blood cells from patients with
leukemia contain an inhibitor of normal granulocyte/macrophage progenitor
(CFU-GM) proliferation (leukemia-associated inhibitory activity, LIA)
identified as acidic isoferritins. A comparison was made of the action of
crude LIA prepared from frozen-thawed leukemic blood cells and purified
spleen ferritin from a patient with chronic myelogenous leukemia, on the
proliferation of blast progenitors from patients with acute myelogenous
leukemia (AML), and on the promyelocytic leukemia cell line, HL-60. Crude
LIA showed no inhibition of blast progenitor or HL-60 proliferation at low
concentrations, but inhibited the proliferation of CFU-GM. At higher
concentrations, crude LIA inhibited both blast cells and CFU-GM. Purified
spleen ferritin failed to inhibit blast progenitors or HL-60 cells at any
concentration tested, but inhibited both 70-day and 14-day CFU-GM. Using
the thymidine "suicide" technique, the action of LIA was confirmed as being
on CFU-GM in S-phase, but it failed to affect the proliferation of blast
cell in S-phase. It is concluded that acidic isoferritins inhibit normal
CFU-GM but not blast cells from patients with AML. Acidic isoferritins
could confer a proliferative advantage of the leukemic clone over its
normal counterparts.
Volume 58,
Issue 3,
pp. 653-657,
09/01/1981
Copyright © 1981 by The American Society of Hematology
