[Diagnosis of stem cell leukemias in view of phenotypic and genotypic analysis]

To identify the biological characteristics of so called stem cell leukemia (SCL), of which leukemic blast cells should be derived from pluripotent stem cells, immunophenotypical and genotypical analysis and response to several hematopoietic cytokines were studied in 272 cases with acute de novo leukemia. In 132 cases with acute myelogenous leukemia (AML), some cases of CD19+ and/or CD7+ AML were considered as SCL. In cases with myeloperoxidase negative acute lymphoblastic leukemia (ALL), cases of CD7 + CD1 - CD3 - CD4 - CD8 - My-Ag (myeloid antigens) +ALL, considered as those of T-precursor ALLs, and cases of HLA-DR + CD19 + CD20 - My-Ag + ALL, considered as those of B-precursor ALLs, were though to be SCL. We did not think the cases of ALL with dual genotype to be SCL, since dual genotype could not be considered as sings of ability to differentiate to multilineage but as products of the process of active V-DJ rearrangements of Ig heavy chain gene.