CD34(-CELLS ARE CD38(-), BUT CD61(+) AND GLYCOPHORIN A(+) - IMPROVED CRITERIA FOR DIAGNOSIS OF AML-M7() MEGAKARYOBLASTIC LEUKEMIC)

The aim of this flow cytometry study ire acute megakaryoblastic leukae mia (AML-M7) was to describe the membrane phenotype of CD34(+) progeni tor subsets and compare these with the phenotypes expressed by other A ML FAB types. Following conventional histopathological diagnosis monon uclear cells from hone marrow and blood were examined in seven patient s with AML-M7 and compared with results from 26 sequential patients wi th AML-M0 to AML-M6. The CD34(+) subsets in AML-M7 patients differed f rom that of patients with AML-M0 to AML-M6 as the CD34(+) CD61(+) and the CD34(+) Glycophorin A(+) subsets were median 31% and 20%, respecti vely, compared to 4% and 2% in the AML-M0 to AML-M6 (P=0.0005). Only 1 % of the CD34(+) progenitors were CD34(+) CD38(+) in AML-M7 compared t o 72% in other AML subtypes (P<0.000). These findings suggest that the CD34(+) cell compartment in AML-M7 consists of early lineage-specific progenitors. In conclusion, flow cytometry analysis of CD34(+) subset s may improve the diagnostic safety in AML-M7 and consequently the pro gnostic significance of immunophenotyping in acute leukaemia.