OBJECTIVETo explore the role of paternal veto cells in preventing graft-versus-host disease (GVHD) after related HLA- haploidentical stem cell transplantation in mice.

METHODSMHC-haploidentical recipient B6CF1(H-2 b/d) mice pretreated with total body irradiation at 9.0 Gy for 4 h before transplantation. The recipient mice were divided into 4 groups, and in the irradiation group, only injection of 0.3 ml D-Hank's liquid was given through the tail vein; in the control group, the mice received injection through the tail vein of 4.5x10(6) bone marrow cells mixed with 3.0x10(7) spleen cells from C57BL/6 mice without the preventive measures of GVHD; the mice in the two experiment groups received cell transplantation in the same manner, and on day 4 after transplantation, 5.0x10(6) and 1.0x10(7)spleen cells from BALB/c mice were injected through tail vein, respectively. The hematopoietic recovery, engraftment and GVHD of the recipient mice were observed.

RESULTSWithout any treatment, all mice in the control group developed GVHD and died after transplantation. In the 10 mice with injection of 5.0x10(6) spleen cells, GVHD occurred in 5 mice with a 30-day survival rate of 50%; the median survival time of the mice with GVHD was 20 days, significantly longer than that of the control mice (14 days, P<0.05). In the 10 mice injected with 1.0x10(7) spleen cells, 2 developed GVHD and the 30-day survival rate was 80% (8/10) with a median survival time of 30 days, significantly longer than that of mice with injection of 5.0x10(6) spleen cells and the control mice (P<0.05).

CONCLUSIONPaternal veto cell transplantation can decrease the occurrence of GVHD after related HLA haploidentical stem cell transplantation in mice.