TIM-3 Is Highly Expressed On Blast Cells In Patients With Acute Myeloid Leukemia

T cell immunoglobulin-3(TIM-3) is known as a negative regulator in anti-tumor immunity through its reaction with TIM-3 ligand, galectin-9. It has been confirmed that TIM-3 is expressed on Th1 cells, dendritic cells, monocytes, macrophages, malignant stem cells and so on. But the expression of TIM-3 and its clinical implications in patients with acute myeloid leukemia(AML) remains unknown. In this study, we sought to determine the expression and clinical implications of TIM-3 in AML. From August 2012 to June 2013, in total of 32 AML patients with sixteen male and sixteen female were enrolled in this study. We collected their peripheral blood before they received any treatment and then obtained their peripheral blood mononuclear cells(PBMC). Monoclonal antibody was added into PBMC and cell population was analyzed by flow cytometry. Blast cells were identified with SSC CD45^±and mature lymphocytes with SSC CD45⁺. The average expression of TIM-3 on blast cells was 43.46%, while on mature lymphocytes was 13.78% (P<0.001). In univariate analysis, the level of expression was not correlated to the percentage of blast cells and there was no difference between each type of AML. Complete remission was similar between different levels of TIM-3 expression(P>0.05). These results demonstrated that TIM-3 was highly expressed on blast cells than on mature cells in AML, which indicated that TIM-3 could be associated with the differentiation of blast cells and a potential marker to detect the tendency of relapse. TIM-3-targeted antitumor therapy presents a perspective possibility.