The phenotype of L-CFU and its correlation with the immunological characteristics of the blast cell population in AML.
The membrane phenotype of AML clonogenic cells (L-CFU) was analyzed in 19 AML patients using an in vitro culture technique after a complement-mediated lysis assay employing a panel of six monoclonal antibodies (McAb) -HLA-DR, FMC56 (CD9), FMC27 (CD9), CD14, CD15, CD41a-. Our results show that L-CFU has a heterogeneous but immature phenotype lacking on the expression of differentiation antigens (CD14, CD15, CD41a). In addition, we observed that the L-CFU phenotype is different from that of the whole blast cell population. Interestingly, L-CFU showed a higher expression of HLA-DR antigens with respect to their progeny. Upon analyzing whether the L-CFU phenotype was related to both the morphological and immunological features of AML blast cells, it was observed that, while there is no correlation with the FAB classification, there was a partial relationship between the immunological phenotype of AML blast cells and that of L-CFU. Accordingly, the more immature AML cases showed a more differentiated L-CFU phenotype (HLA-DR+, CD9+, FMC27+) when compared with cases with a more mature blast cell phenotype. These results suggest that those AML cases with a relatively immature myeloblastic phenotype may arise from a progenitor cell that has undergone partial differentiation and that is unable to acquire myeloid differentiation antigens, while those AML cases with mature blast cells might emerge from a very early L-CFU that has the capacity to undergo a greater degree of differentiation.
Servicio de Hematologia, Hospital Clinico Universitario, Universidad de Salamanca, Spain.
M C
MC
del Cañizo
J
J
Almeida
J F
JF
San Miguel
A
A
Orfao
M
M
Gonzalez
A
A
Lopez Borrasca
D015703:Antigens, CD / Q000032:analysis; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000276:immunology*; D008562:Membrane Glycoproteins; D014411:Neoplastic Stem Cells / Q000276:immunology*; D060245:Tetraspanin 29; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; C554869:CD9 protein, human; D006684:HLA-DR Antigens; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29