Decreased Tim-3 Expression Level of Peripheral Blood Natural Killer Cells in Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life threatening disease characterized by severe pancytopenia and bone marrow failure. T-cell immunoglobulin- and mucin domain-containing (Tim)-3 has been initially used to identify dysfunctional T cells, but recent studies have demonstrated that Tim-3 is widely detected on nature killer cells (NK cell) and may serves as a marker for activation and maturation of NK cells. In our study, Tim-3, expressed on peripheral blood of NK cells in SAA patients, was quantitatively analyzed by Flow cytometry before and after immunosuppressive therapy (IST). Results showed that the expression of Tim-3 in patients before IST [(61.11±15.46)%] was significantly lower than that in patients after IST[(74.30±12.63)%, P<0.05] and normal controls[(70.39±12.73)%, p<0.05]. However, no difference was observed between patients before and after IST. Therefore, we concluded that low expression of Tim-3 in NK cells may play a crucial role in early stage of SAA.