DIAGNOSIS OF ACUTE MYELOID-LEUKEMIA AND SYSTEM COULTER VCS

Background. The aim of this study was to evaluate the possible contrib ution VCS could make in a hematological laboratory for the diagnosis o f acute myeloid leukemia (AML). Materials and Methods. Peripheral bloo d samples from 42 AML patients and 58 normal donors were analyzed by f low cytometry with the VCS. Normal and leukemic peripheral blood sampl es were tested to establish a correlation between VCS data and the ref erence manual method. We evaluated the sensitivity threshold of the VC S for blast cell detection in progressively diluted samples. We looked at a correlation between different scatterplots and flags and the FAB classification of acute myeloid leukemia in order to identify a chara cteristic VCS image for each subtype. Thirty-four bone marrow samples (18 normal donors and 16 leukemic patients) were analyzed by the VCS s ystem to demonstrate a characteristic scattergram distribution. Furthe r, we tried to compare scatterplots to the flags of leukemic bone marr ow samples and, finally, we compared VCS scatterplots with aberrant an tigen expression in AML cases. Results and Conclusions. Overall VCS sp ecificity was 93.1% (54/58) in peripheral blood samples; sensitivity w as 100% (42/42) and VCS efficiency was 96%. In AML the characteristic X6 flag was observed in 95.23% of the cases (40/42). In peripheral sam ples discrimination was made between AML M1 with agranular blasts >50% of the non erythroid cells (NEC), M4, M5 on the one hand, and AML M1 with granular blasts >50% of NEC, M2, M3 on the other: the X5 flag was often present in the second group because of the different localizati on of the cells (p = 0.001). In all normal bone marrow samples we obse rved granuloblasts in different maturation stages in the neutrophil re gion of the DF1 VCS scatterplot corresponding to the X5X6 flags or, ra rely, to the X5X6X1, because of the presence of immature erythroid cel ls. This association X5X6 was never observed alone in patients affecte d by AML. In our study, it was difficult to identify peculiar scatterp lots and alarms for each FAB class of AML. Nevertheless, we observed t hat in all M4 and M5 FAB cases the blastic cells both in the periphera l blood and in the bone marrow samples were located in the monocyte re gion, with the frequent presence of the X3 flag often associated with the X6 flag. Eight out of the 16 AML bone marrow samples (1 FAB M0, 1 M2, 1 M3, 2 M4, 3 M5) showed the X2 flag and partial localization of b lasts in the lymphoid region. In all these cases the presence of some small blastic cells with agranular cytoplasm was confirmed by morpholo gical observation and cytochemical stainings.