Assessment of the normal or leukemic nature of CD34+ cells in acute myeloid leukemia with low percentages of CD34 cells.
OBJECTIVE
The percentages of CD34+ cells in the bone marrow of patients with acute myeloid leukemia (AML) vary widely. Especially in the low range (<5% CD34+ cells), the nature (normal or malignant) of the CD34+ cells is uncertain. Since only in a minority of cases are molecular techniques applicable, in this study we explored a multiparameter approach using phenotypic and functional characteristics to discriminate normal CD34+ cells from malignant ones.


METHODS
CD34+ cells from 24 AML patients with <5% CD34+ cells and from 3 patients with >50% CD34+ cells were studied immunophenotypically for aberrant phenotypes, CD133 and CD90 expression and for P-glycoprotein activity.


RESULTS
In the low (0.02-0.7%) CD34+ range, our approach offered strong evidence for a normal origin of the CD34+ cells in 18/19 cases, which was confirmed by interphase fluorescent in situ hybridization on sorted CD34+ cells in 3 cases, which had concomitant presence of cytogenetic abnormalities in the CD34- blasts. In contrast, in the intermediate (1.6-3.5%) CD34+ range, the CD34+ cells appeared as normal in only 1/5 cases. In the high (51-67%) CD34+ range, as expected the majority of CD34+ cells were malignant, although in 2/3 cases a small subpopulation (i.e. 0.15% and 0.20%) of CD34+ cells were of normal origin.


CONCLUSIONS
Our multiparameter approach enabled us to define the nature of CD34+ cells in AML. This has implications for studies dealing with the characterization of primitive malignant cells. Moreover, it enabled identification of truly CD34 negative AML, which would be eligible for CD34-based immunological purging of autologous stem cell transplants.
van der Pol
Marjolein A
MA
Department of Hematology, VU University Medical Center, Amsterdam, The Netherlands.
Feller
Nicole
N
Roseboom
Marjet
M
Moshaver
Bijan
B
Westra
Guus
G
Broxterman
Henk J
HJ
Ossenkoppele
Gert J
GJ
Schuurhuis
Gerrit J
GJ
D000208:Acute Disease; D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000096:biosynthesis*; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000473:pathology*; D006801:Humans; D007951:Leukemia, Myeloid / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged
D018952:Antigens, CD34