Abstract:

BACKGROUND: The connection between Natural killer (NK)-cells and allogeneic bone marrow transplantation (allo-BMT) has aroused increasing attention.
OBJECTIVE: To explore the effect of NK cells on graft rejection, hematopoietic and immune reconstitution in mouse undergoing allo-BMT.
METHODS: Lethally and nonlethally irradiated BALB/c (H-2d) mice were transplanted with C57BL/6(H-2b) bone marrow plus donor peripheral T cells and/or NK cells.
RESULTS AND CONCLUSION: Compared with lethally irradiated and allo-BMT group without infusion of NK cells, the survival rate in lethally irradiated and allo-BMT group with infusion of NK cells significantly enhanced; leukocytes count, expression level of CD19+ and CD34+ cell count recovered rapidly; expression level of H-2b+ cell obviously increased. Expression level of CD34+ cell in the group with infusion of NK cells was obviously lower than that of the group without infusion of NK cells at 28 days after transplantation, but there was no significant difference between the 2 groups at 60 days (P > 0.05). In nonlethally irradiated and allo-BMT group without NK cell infusion, expression level of H-2b+ cell significantly decreased at 30 days after transplantation, and reduced to before transplantation level at 60 days; while expression of H-2b+ cell yet could be detected with more than 80% at 60 days after transplantation in group infused with high and low concentration of NK cells. In allo-BMT mice, alloreactive NK cell inhibits graft rejection, enhances engraftment, promotes the reconstitution of hematopoiesis and immunity, and increases survival rates.