Research paperDecreased TIM-3 expression of peripheral blood natural killer cells in patients with severe aplastic anemia

- TIM-3 expression on NK cells was decreased in SAA, and recovered to normal after IST.
- TIM-3 level on NK cells was correlated with the severity of pancytopenia of SAA.
- The dysfunction of NK cells might play an important role in pathogenesis of SAA.
- IST could improve the differentiation and function of NK cells in SAA patients.

Severe aplastic anemia (SAA) is an autoimmune disease characterized by severe pancytopenia and bone marrow failure. In our previous studies, we found natural killer (NK) cells were aberrant in SAA patients. T cell immunoglobulin mucin-3 (TIM-3), an important regulator of immunity, is widely detected on NK cells and may contribute as a marker of activation and maturation of NK cells. In this study, we found that SAA untreated patients had lower TIM-3 expression on NK cells and CD56dim NK subsets compared with normal controls, and were correlated with the severity of pancytopenia of SAA. After immunosuppressive therapy (IST), TIM-3 expression recovered to normal level. Moreover, the TIM-3 mRNA levels in NK cells significantly increased in SAA remission patients after IST. We inferred that low expression of TIM-3 on NK cells might lead to NK cells dysfunction and involve in the progress of bone marrow failure in SAA.