Effect of NK cell on GVHD and hematopoietic reconstitution after Hª²2 haploidentical bone marrow transplantation in mice

    ZHANG Mei, WU Di, XU Hui, HE Pengª²Cheng, LI Jing, XI Jieª²Ying, CAI Ruiª²Bo, LIU Yaª²Lin

    Department of Hematology, First Affiliated Hospital, Medical College, Xi¬ðan Jiaotong University, Xi¬ðan 710061, China

    ¡¾Abstract¡¿ AIM: To explore the effect of natural killer (NK) cell on graftª²versusª²host disease (GVHD) and hematopoietic reconstitution after Hª²2 haploidentical bone marrow transplantation in mice. METHODS: Murine model of Hª²2 haplotype mismatched bone marrow transplantation was established by using Balb/c (Hª²2d) mouse as recipient, and Balb/c (Hª²2d)¡ÁC57BL/6(Hª²2b)(Hª²2d/b) mouse as donor. Lethally irradiated Balb/c (Hª²2d) mice were transplanted with Balb/c (Hª²2d)¡ÁC57BL/6(Hª²2b)(Hª²2d/b) bone marrow plus with donor periª²pheral T cells and/or NK cells. GVHD and hematopoietic reconstitution were observed and evaluated by clinical manifestations, pathological changes and WBC counting. RESULTS: In the bone marrow plus with T cells group, GVHD was induced in 90% mice and the recovery of the WBC needed 4 weeks averagely; but in the group plus with low concentration of NK cells, GVHD was induced in 20% mice and the recovery of the WBC was 3 weeks averagely; and in the group transplanted with high concentration of NK cells, GVHD was induced only in 10% mice and the recovery of the WBC was 3 weeks averagely. Compared with the group transplanted only with T cells, the incidences of GVHD in the later two groups decreased obviously (P<0.01), and the recovery of the WBC was in a shorter time (P<0.01). CONCLUSION: In mouse Hª²2 haploidentical bone marrow transplantation, alloreactive NK cells can reduce the incidence of GVHD and promote hematopoietic reconstitution. ......