Increased CD34+CD38 -CD123 + cells in myelodysplastic syndrome displaying malignant features similar to those in AML

Leukocyte interleukin-3 receptor α (CD123) is regarded as a marker of leukemia stem cells. We previously found that CD123 was also highly expressed on CD34(+)CD38(-) cells in myelodysplastic syndrome (MDS) patients, but it is unclear whether the level and the characteristics of CD34(+)CD38(-)CD123(+) cells in MDS are similar to those in acute myeloid leukemia (AML). Based on previous research by our team, we further enlarged the specimens and found that the mean proportion and the mean MFI of CD34(+)CD38(-)CD123(+) cells in low-grade MDS were lower than that in AML, and those in high-grade MDS were similar to those in AML. CD34(+)CD38(-)CD123(+) cells expressed lower granulocyte stimulating factor receptor, CD11b, and apoptosis molecule (Annexin V), meanwhile, these cells showed upregulation of transcription factors (GATA-1, GATA-2) and transferrin receptor (CD71) in MDS and AML. Furthermore, an increase in CD34(+)CD38(-)CD123(+) cells was closely related to the number of cytopenias involving hematopoietic lineages, anemia, blast count in bone marrow smear, fluorescence in situ hybridization analysis and WHO prognostic scoring system score. Thus, increases in CD34(+)CD38(-)CD123(+) cells may reflect malignant clonal cells with aberrant differentiation, overproliferation, and decreased apoptosis in MDS, which were similar to AML. CD123 may thus be a promising indicator for identifying malignant clonal cells in MDS and a candidate for targeted therapy.