[Expression of Costimulatory Molecule Tim3 on NK Cells and Its Subsets in Patients with Acute Myeloid Leukemia]

To investigate the expression of costimulatory molecule Tim3 and its subsets on NK cells in patients with acute myeloid leukemia.

30 patients with acute myeloid leukemia treated in our hospital from August 2016 to August 2018 were randomly selected as the AML group, and 30 healthy persons in our hospital during the same period were randomly selected as the control group. The expression levels of CD56^dim NK cells/CD3^-CD56⁺NK cells and Tim3 on CD56^dimNK cells in peripheral blood, CD56^bright NK cells/CD3^-CD56⁺NK cells and Tim3 on CD56^brightNK cells in peripheral blood of the two groups were estimated. The expression of CD3^-CD56⁺NK cells/lymphocytes and their Tim3, CD56^dimNK cells/CD3^-CD56⁺NK cells and their Tim3 expression, Tim3⁺NK, Tim3^-NK IFN-gamma secretion levels before and after chemotherapy in the AML group were analyzed.

The expression levels of CD56^dim NK cells/CD3^-CD56⁺NK cells and their Tim3 in peripheral blood of the AML group were significantly lower than those of the control group (P<0.05). The expression levels of CD56^bright NK cells/CD3^-CD56⁺NK cells and their Tim3 in peripheral blood of the AML group were significantly higher than those of the control group (P<0.05). CD3^-CD56⁺NK cells/lymphocytes and Tim3⁺/CD3^-CD56⁺NK cells in complete remission patients were significantly higher than at initial diagnosis (P<0.05). CD3^-CD56⁺NK cells/lymphocytes and Tim3⁺/CD3^-CD56⁺NK cells in patients with course of treatment ≥2 times and remission patients time more than 3 months were significantly higher than those in patients with chemotherapy course 1 time and remission time≤3 months (P<0.05). The expression levels of CD56^dim NK cells/CD3^-CD56⁺NK cells and their Tim3 in peripheral blood of patients at complete remission were significantly higher than at initial diagnosis (P<0.05). The expression levels of CD56^bright NK cells/CD3^-CD56⁺NK cells and Tim3 in peripheral blood of patients at complete remission were significantly lower than of the patients at initial diagnosis (P<0.05), and the IFN-gamma secretion level of Tim3⁺ NK cells was significantly lower than that of Tim3^-NK cells in these patients (P<0.05).

The expression of costimulatory molecule Tim3 in NK cells and its subsets of patients with acute myeloid leukemia is down-regulated.