[Expression and Function of MAIT Cells in Patients with Newly Diagnosed Acute Myeloid Leukemia]

To explore the changes in number and immune function of mucosal-associated invariant T (MAIT) cells in peripheral blood of patients with newly diagnosed acute myeloid leukemia (AML), and its correlation with the occurrence and development of AML.

Seventy-five clinical samples of patients with newly diagnosed AML and 48 healthy control samples in our hospital from January 2022 to February 2023 were included. Multiparametric flow cytometry was used to detect the number of MAIT cells, membrane surface markers, effector phenotypes and functional indicators in the samples.

Compared with healthy controls, the percentage of MAIT cells in CD3⁺ T cells in peripheral blood of newly diagnosed AML patients was significantly reduced ( P < 0.001). The percentage of MAIT cells in all CD3⁺ T cells in bone marrow of AML patients was similar to that in peripheral blood (P >0.05). Most of MAIT cells in peripheral blood of AML patients were effector memory T cells. Compared with healthy controls, the proportion of effector memory MAIT cells decreased ( P < 0.05), while the proportion of terminally differentiated effector memory MAIT cells and PD-1⁺MAIT cells increased significantly (both P < 0.05). AML patients' peripheral blood MAIT cells expressed significantly higher levels of granzyme B and perforin than healthy controls (both P < 0.05), and secreted significantly lower levels of cytokines such as gamma interferon and tumor necrosis factor α than healthy controls (both P < 0.001).

Compared with healthy controls, the proportion of MAIT cells in AML patients is reduced and the expression of functional markers is abnormal, suggesting that their function is impaired and may be involved in the occurrence and development of AML.