[Experimental study of donor natural killer cells reducing graft-versus-host disease and enhancing engraftment]

The purpose of this study was to investigate whether pretransplant infusion of reactive natural killer cells (NK cells) from donor or recipient can reduce graft-versus-host disease (GVHD) and enhance engraftment in bone marrow transplantation (BMT). Recipient BALB/c mice were divided into 4 groups after received 6.5 Gy total-body irradiation (TBI): control group 1 was treated with nothing, control group 2 received BMT alone, experiment group 1 received BMT and autoreactive NK cells, experiment group 2 received BMT and alloreactive NK cells. Life span, clinical and pathologic changes of GVHD and chimerism rate of each group were evaluated. The results showed that all mice were survival in control group 1. The life span was shorter in experiment group 1 than that in control group 2 (P < 0.05) and longer in experiment group 2 than that in control group 2 (P < 0.01). GVHD was higher in score of experiment group 1 than in control group 2 (P < 0.05) but lower in experiment group 2 than that in control group 2 (P < 0.01). The donor chimerism rate in both two experiment groups were higher than that in control group 2 (P < 0.05), however, the donor chimerism rate was higher in experiment group 2 than that in experiment group 1 (P < 0.01). It is concluded that pretransplant infusion of alloreactive donor NK cells can prolong life span, reduce the degree of GVHD and enhance engraftment. But autoreactive recipient NK cells can shorten life span, aggravate the degree of GVHD and also enhance engraftment, which is weaker than that using alloreactive donor NK cells.