title: Phenotypic heterogeneity of erythroblasts in erythroblastic leukemia revealed by monoclonal antibodies.
abstract: Eight cases each of erythroleukemia (AML-M6) and erythroblastic crisis of chronic granulocytic leukemia (CGLBC-E) were immunophenotyped with the help of a panel of lineage-associated monoclonal antibodies (McAbs). The latter included those reactive with erythroid progenitor (BFU-E and CFU-E) and erythroid precursors at different stages of maturation. In six of eight cases of AML-M6, erythroblasts revealed an immature phenotype, as evident from reactivity of the blast cells with McAbs directed against the earlier stages of erythroid maturation. One case had the phenotype of CFU-E, and in the remaining case of AML-M6 the erythroblasts showed a "mature" surface antigenic profile. This immunophenotypic spectrum was unrelated to the morphologic maturity of the erythroblasts. In two cases of CGLBC-E, an early erythroblastic phenotype was observed, while in as many cases a "mature" phenotype was present. Four of eight cases, however, revealed a mixed, erythroid plus myeloid phenotype. In one of the four cases, two separate blast populations, which represented erythroblasts and myeloblasts, could be identified. In the remaining three cases the blasts were morphologically homogeneous and undifferentiated. High incidence of HLA-DR positivity in the latter three cases suggests the primitive nature of blasts cells and their closeness to the putative "bipotent" myeloid stem cell. Our study has shown phenotypic heterogeneity of blast cells in AML-M6 and CGLBC-E.
mesh_terms: D000911:Antibodies, Monoclonal; D001752:Blast Crisis; D004900:Erythroblasts / Q000502:physiology*; D006801:Humans; D007158:Immunologic Techniques; D004915:Leukemia, Erythroblastic, Acute / Q000473:pathology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000473:pathology*; D010641:Phenotype
chemical_list: D000911:Antibodies, Monoclonal