Aberrant expression of T cell activation markers and upregulation of Tregs in bone marrow and peripheral blood in acute myeloid leukemia patients

T cells' function and activation and the immunosuppressive effect of regulatory T cells (Tregs) play a pivotal role in the occurrence and progression of acute myeloid leukemia (AML). In this study, we investigate the expression of T cell activation markers and quantity of Tregs in bone marrow (BM) and peripheral blood (PB) from AML patients and further characterized their correlation with BM leukemic blasts. Expression of CD25, CD38, CD69, and HLA-DR on the surfaces of CD4 + and CD8 + T cells and the quantity of Tregs in BM and PB from new diagnosed (ND), relapsed-refractory (RR), complete remission (CR) AML patients were measured via flow cytometry. Compared to normal controls (NC), we found higher proportion of CD4 + CD69 + T cells, CD8 + CD69 + T cells and Tregs in PB. CD8 + CD38 + T cells and CD8 + HLA-DR + T cells in RR were significantly higher than ND, CR and NC). Tregs were normalized when AML patients achieved CR. Moreover, there was a minor positive correlation between AML blasts and CD8 + CD25 + T cells or Tregs, while AML blasts had a minor negative correlation with CD4 + CD69 + T cells. Abnormal activation markers of T cells and Tregs may be involved in the pathological mechanism of ND and RR AML. Our results indicated that CD8 + CD38 + T cells and CD8 + HLA-DR + T cells might be RR markers of AML patients. Furthermore, Tregs could be used as clinical indicators to evaluate prognosis for AML patients.