Abstract： Objective To investigate the relationship between the soluble LAIR-1(sLAIR-1)in the serum from recipients after transplant and graft rejection.Methods Serum sLAIR-1 level was determined by double mAb sandwich enzyme linked immunosorbent assay on 23 cases of liver transplantation and 139 cases of kidney transplantation.Results In healthy volunteers and 98 recipients with normal graft function,sLAIR-1 was detected at low level [(4.3±2.3)μg/L and(6.3±3.7)μg/L],with the difference being not significant.In 6 cases of liver acute rejection,20 cases of kidney acute rejection and 5 cases of graft loss,serum sLAIR-1 levels were increased remarkably at high 1evels [(47.2±25.9)μg/L,(36.3±14.7)μg/L,and(28.8±9.4)μg/L respectively]as compared with the two groups of healthy volunteers and the recipients with normal graft function,even peaked at 117.3 μg/L in one case of severe liver rejection.Meanwhile,in 5 cases of liver chronic rejection,27 cases of kidney chronic rejection and 6 cases under dialysis treatment.the levels of sLAIR-1 were(16.1±6.4)μg/L,(13.1±5.5)μg/L and(11.2±4.6)μg/L respectively,significantly higher than those of the healthy volunteers and the recipients with normal graft function.Conclusion sLAIR_1 was detected at high level in the recipients suffered graft acute or chronic rejection and might be a promising monitor of rejection after transplantation.