Clinical significance of Treg cell frequency in acute myeloid leukemia

This study was designed to investigate the clinical significance of peripheral blood CD4⁺ CD25⁺ CD127 low-regulatory T (T_reg) cells in acute myeloid leukemia (AML) patients. T_reg cells in the peripheral blood of 80 AML patients and 35 age-matched healthy controls were counted by flow cytometry. Correlations between the frequency of circulating T_reg cells and disease status, treatment outcome, or prognosis were evaluated. The percentages of T_reg cells in patients at diagnosis and during refractory/relapse were significantly higher than that in healthy controls. There was no significant difference in the percentages of T_reg cells between patients in remission and healthy controls. After six cycles of chemotherapy, the percentage of T_reg cells in patients who achieved complete remission was significantly lower than that in patients at diagnosis, but there was no difference in T_reg frequency between refractory/relapse patients and patients at diagnosis. T_reg cells in the peripheral blood of AML patients may play a suppressive role in host antitumor immune response. The frequency of T_reg cells in peripheral blood may thus be used as a biomarker for predicting sensitivity to chemotherapy and prognosis of AML patients. Additionally, T_reg number in peripheral blood could be used to monitor disease status and evaluate disease progression.