Monocytic Myeloid-Derived Suppressor Cells But Not Monocytes Predict Poor Prognosis of Acute Myeloid Leukemia

OBJECTIVE: Some reports suggest that high absolute monocyte count (AMC) at diagnosis is an independent predictor of poor prognosis in acute myeloid leukemia (AML), but others disagree. Monocytic myeloid-derived suppressor cells (Mo-MDSCs) are immature monocytes. This study aimed to compare the value of monocytes and Mo-MDSCs in predicting the prognosis of AML. MATERIALS AND METHODS: Peripheral blood samples from 107 newly diagnosed patients with AML and 47 healthy controls (HCs) were collected. We validated the clinical significance of AMC, monocyte count (CD14(+)CD45(++)), and Mo-MDSC count (CD14(+)HLA-DRlow/-CD45(++)) for initial induction therapy response, maintenance of treatment effects, and long-term survival. RESULTS: Compared with HCs, the levels of AMC, monocyte count, and Mo-MDSC count were all significantly higher among patients with AML. However, only elevated Mo-MDSC count was significantly associated with lower complete remission rate, higher relapse/refractory rate, and poorer long-term survival. CONCLUSION: Mo-MDSCs but not monocytes predict the poor prognosis of AML.