In vitro differentiation of leukemic cells to eosinophils in the presence
of interleukin-5 in two cases of acute myeloid leukemia with the
translocation (8;21)(q22;q22)
H Ema, K Kitano, T Suda, Y Sato, K Muroi, M Ohta, M Yoshida, S Sakamoto, M Eguchi and Y Miura
Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
We demonstrated the significant eosinophilic growth of leukemic cells in
the presence of interleukin-5 (IL-5) in 2 of 15 cases of acute myeloid
leukemia. These two cases were M2 (FAB classification) with the
translocation (8;21)(q22; q22). Bone marrow examination revealed the rather
high percentages (6% and 9%) of atypical eosinophils in the total nucleated
bone marrow cells in these two cases. In the remaining 13 cases,
eosinophils were less than 2% in the nucleated bone marrow cells. In the
methylcellulose culture system, 142 +/- 18 or 54 +/- 2 colonies were formed
by 5 x 10(4) mononuclear cells in the presence of IL-5 in these two cases.
These colonies mainly comprised mature eosinophils. Eosinophils were
confirmed by Biebrich scarlet staining and electron microscopic examination
using a specific lectin binding assay. The eosinophilic differentiation and
proliferation of leukemic cells were also observed in the liquid culture
system. It was shown that eosinophils observed in both systems were derived
from leukemic cells using the chromosomal marker of leukemic cells,
t(8;21). Leukemic cells also differentiated to neutrophils or both
neutrophils and eosinophils in response to granulocyte colony-stimulating
factor or interleukin-3, respectively, but did not respond noticeably to
granulocyte-macrophage colony-stimulating factor. Although IL-5 acts on
normal eosinophil committed precursors as a lineage-specific growth factor,
at least some leukemic cells reacted to IL-5 and could proliferate and
differentiate along eosinophilic pathway. Our findings suggest that
atypical eosinophils observed in the bone marrow were derived from the
leukemic clone in two cases of AML.
Volume 75,
Issue 2,
pp. 350-356,
01/15/1990
Copyright © 1990 by The American Society of Hematology
