[Flow cytometric detection of minimal residual disease in pre-cursor-B-acute lymphoblastic leukemia on the basis of phenotypic aberrancies on minor leukemic cell populations].

To test the European BIOMED-1 Concerted Action proposed technique to detect minimal residual disease (MRD) in the chinese patients with precursor-B-acute lymphoblastic leukemia (precursor-B-ALL) by triple-staining flow cytometry and to define both normal and aberrant phenotypic profiles of precursor B cells, a series of bone marrow samples, 35 from precursor-B-ALL (13 in newly diagnosed cases, 15 at the end of remission induction therapy and 7 at end of the consolidations), and 19 from normal controls, were immunophenotyped with the five triple-staining antibodies (TdT/CD10/CD19, CD10/CD20/CD19, CD34/CD38/CD19, CD34/CD22/CD19 and CD19/CD34/CD45) recom-mended by the BIOMED-1 using common flow cytometric protocols. Further, with different ratios of the leukemic cells with CD34/CD38/CD19 phenotype and normal mononuclear cells, a serial dilution test was analyzed. The results showed that three major CD19(+) cell subpopulations were identified in the normal controls, representing three consecutive maturation stages.