Flow cytometric quantification and immunophenotyping of leukemic stem cells in acute myeloid leukemia.

Leukemic stem cells (LSCs) are root of clonal growth in acute myeloid leukemia (AML) and responsible for the propagation of leukemic blasts (LBs). LSCs are considered as CD34 + CD38- population among LBs and often express as CD123, CD44, or CD184, which are rarely expressed on normal hematopoietic stem cells and could be the potential therapeutic targets. Using multi-color flow cytometry, we analyzed the proportions of CD34 + CD38- LSCs and expression of CD123, CD44, and CD184 on LSCs in 63 patients with AML. The median proportion of LSCs was 1.3 % (0.0-33.1 %) at the time of diagnosis. Of all patients, 74.6 % of them had CD123-positive LSCs, all patients had CD44-positive LSCs, and 85.7 % had CD184-positive LSCs, respectively. The proportions of LSCs were significantly lower in the complete remission (CR) group compared with non-CR group (P = 0.006). The lower proportions of LSCs in CR group indicated that measurement of the proportion of LSCs might be helpful to predict the prognosis of AML.