Page 195 - Haematologica March 2020

may help to identify novel treatment options and patient subgroups with sensitivity to a specific targeted therapy.
AML is diagnosed when the bone marrow (BM) con- tains at least 20% of myeloid lineage blast cells, and hematological relapse is defined when the BM exceeds 5% of blasts. The non-blast cells of the AML BM are com-
prised of other cell types, mainly lymphocytes and more mature leukemic cells (monocytes, granulocytes) or healthy cells. The BM content and the maturity level of leukemic cells is reflected in the French-American-British (FAB) subtypes.8 In FAB M0/1 subtypes, the differentiation blockade occurs at the early myeloid progenitor stage,
Venetoclax response and maturation stage in AML
A
B
C
Figure 1. Study outline and gating strategy. (A) Schematic outline of the experimental setup. (B) Gating strategy of cell populations. Dead and apoptotic cells were stained with 7-AAD and Annexin V, respectively, and cells negative to these markers were gated as live cells. CD45dim/SSClow and CD34+ population was used as the standard gate for acute myeloid leukemia (AML) blast cells. For samples with blast cells negative for CD34, CD45dim/SSClow and CD33 positivity was used to identify blasts. Lymphocytes were gated based on CD45bright/SSClow and were confirmed to be CD33 negative. Immature granulocytes (present after Ficoll gradient centrifu- gation) were gated based on CD45dim/SSChigh, CD33+ and CD34–. Monocytes were identified based on CD14 positivity. Clinical immunophenotype data were obtained for all samples to validate the gated cell populations. The illustration shows patient sample 6323 at day 0. (C) Illustration of the immunophenotypic profiles of AML samples with different French-American-British (FAB) subtypes and healthy bone marrow (BM) samples represented by CD45 versus SSC plots at day 0.
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