Pre-Infusion of Allogeneic Lymphocytes Treated with 5-FU Induced Positive Expression of Fas-L in Rat Liver Graft

Objective To evaluate the effect of pre-infusion of allogeneic lymphoyctes treated with 5-FU on the rat liver graft.Methods Rat liver transplant models from Wistar to SD were established.Four groups were designed as following: control group: only liver transplantation without any other intervention;lymphocytes group: 1 ml of untreated lymphocytes(5×106/ml) from Wistar rats were pre-infused into SD rats on day 7 and 4 separately before transplantation;lymphocytes with low concentration of 5-FU group: low concentration 5-FU(7.5 μg) treated lymphocytes were pre-infused as above;lymphocytes with high concentration of 5-FU group: high concentration 5-FU(15 μg) treated lymphocytes were pre-infused as above.Fas-L and CD8 expression were detected by immunohistochemistry method on day 7 after transplantation.Results The integral opticaldensity(IOD) of Fas-L positive lymphocytes in the lobules of liver and portal areas were higher in lymphocytes with low concentration of 5-FU group than in the other groups(P0.05).There was no difference between lymphocyte group and lymphocytes with high concentration of 5-FU group(P0.05).The IOD of CD8+ expression in lobules of liver was not different among all the three lymphocytes treated groups(P0.05).But in portal areas,CD8+ expression was lower in the lymphocytes with low concentration of 5-FU group than in the other groups(P0.05).Conclusion Pre-infusion of lymphocytes treated with low concentration 5-FU can induce graft immune tolerance,the probable mecanism of which is the increasing Fas-L expression in graft.