The effectiveness of a novel treatment of TIM‐3(−) NK cells infusion in murine models of immune‐mediated bone marrow failure

Abstract Background T‐cell immunoglobulin and mucin‐containing domain (TIM)‐3 exerts its inhibitory effect on NK cells and participates in the immune pathogenesis of SAA. In this study, we aimed to explore a novel treatment method of TIM‐3(+) NK or TIM‐3(−) NK cell infusion in combination with immunosuppressive therapy for bone marrow failure (BMF)/aplastic anemia (AA) mice. Methods BMF/AA mouse model was constructed. The TIM‐3 expression and functional molecules on TIM‐3(+) and TIM‐3(−) NK cells of the BMF group, total body irradiation (TBI) group, and normal control (NC) group mice were detected by flow cytometry. After treatment, the general condition, whole blood cell and bone marrow cell (BMC) count, and immune condition of mice from each group were compared. Results TIM‐3 expression in the peripheral blood NK cells of BMF mice was significantly lower than that of the TBI and NC group mice. TIM‐3(−) NK cells expressed more NKG2D receptors than TIM‐3(+) NK cells. The levels of P‐Akt and PI3K in TIM‐3(−) NK cells were higher than those in TIM‐3(+) NK cells. On the 17th day after BMF induction, the weight, peripheral whole blood cell count, and BMC count of BMF mice decreased significantly compared with that of the NC group mice. The therapeutic effect in the TIM‐3(−) NK cell treatment group was better than that in the TIM‐3(+) NK cell treatment and CsA treatment groups. Concurrently, the ratio of CD4 + T and CD8 + T cells of BMF mice was significantly lower than that of the NC group mice. The therapeutic effect in CsA + TIM‐3(−) NK group was more significant than that of the CsA treatment and the CsA + TIM‐3(+) NK groups. Conclusions In this study, we found that the general condition, peripheral whole blood cell and BMC count, and immune status of BMF mice improved significantly after CsA + TIM‐3(−) NK cell treatment. These results may provide further insights into the immune pathogenesis of SAA and novel therapeutic ideas for improving SAA treatment.