Clinical value of the quantitative expression of the three epitopes of CD34 in 300 cases of acute myeloid leukemia.
OBJECTIVE
The various epitopes of the CD34 molecule have been classified according to their different sensitivities to enzymatic cleavage by neuraminidase, chymopapain and a glycoprotease from Pasteurella haemolytica. Although monoclonal antibodies have been developed that specifically identify these epitopes, few studies have evaluated the distribution and quantitative expression of such epitopes on leukemic blasts.


METHODS
We report here a prospective multicenter study in which we examined and quantified the expression of the 3 classes of CD34 on fresh leukemic blast cells from 300 cases of acute myeloid leukemia (AML). The binding of monoclonal antibodies was studied by flow cytometry, allowing evaluation of blast cell positivity as well as their mean fluorescence intensity. These quantitative data were made comparable between centers by means of a calibration curve established with the same reagents in all laboratories.


RESULTS
Quantitative expression of class I epitope was significantly higher than that of class II and class III epitopes (p<0.0001). The three classes were more frequently expressed in M0 and M1 and less in M3 and M5. The highest levels of CD34 expression were observed in M2, M0 and M1 and the lowest in M3, M5 and BAL for class II and III. CD34 expression was lower for all classes in cases with a normal karyotype, compared to in cases with structural or numerical abnormalities.


CONCLUSIONS
In cases with a t(9;22) the expression of class I was significantly higher than that of class II and III and the opposite was observed in AML with t(15;17). Moreover, as a whole, a high intensity of class III CD34 appeared to be a marker of good prognosis.
Maynadié
Marc
M
Service d'Hématologie biologique, CHU de Dijon, 2 Boulevard Maréchal de Lattre de Tassigny, 21034 Dijon Cedex, France. mmaynadie@chu-dijon.fr
Gerland
Luc
L
Aho
Serge
S
Girodon
François
F
Bernier
Michel
M
Brunet
Corinne
C
Campos
Lydia
L
Daliphard
Sylvie
S
Deneys
Véronique
V
Falkenrodt
Annie
A
Jacob
Marie-Christine
MC
Kühlein
Emilienne
E
LeCalvez
Geneviève
G
Moskovtchenko
Philippe
P
Philip
Patrick
P
Carli
Paule-Marie
PM
Faure
Gilbert C
GC
Béné
Marie-Christine
MC
D000208:Acute Disease; D018952:Antigens, CD34 / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D002138:Calibration; D018572:Disease-Free Survival; D000939:Epitopes / Q000145:classification / Q000276:immunology*; D005434:Flow Cytometry; D005470:Fluorometry; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006801:Humans; D016130:Immunophenotyping / Q000295:instrumentation / Q000379:methods; D007951:Leukemia, Myeloid / Q000145:classification / Q000276:immunology* / Q000401:mortality / Q000473:pathology; D015993:Life Tables; D014411:Neoplastic Stem Cells / Q000276:immunology*; D010677:Philadelphia Chromosome; D011379:Prognosis; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results
D018952:Antigens, CD34; D000951:Antigens, Neoplasm; D000939:Epitopes