Preliminary Study On Expression Of The Human Leukocyte Antigen-G After Organ Transplantation

Human leukocyte antigen (HLA)-G is a human nonclassical MHC class I molecule characterized by a reduced polymorphism of 15 alleles and only seven proteins (G1-G7). HLA-G1-G4 are membrane-bound molecules, while HLA-G5-G7 are the soluble. HLA-G displays immunotolergentic properties towards the main effector cells involved in graft rejection through inhibition of NK- and CTL-mediated cytolysis and CD4+ T cell alloproliferation. NK cells and alloreactive CD4+ and CD8+ T cells play a crucial role in the rejection of allografts. In light of these, HLA-G is a tolerance molecule, which would be taken into account for the monitoring of transplantation.Because the structure and functions of HLA-G5 was confirmed. Soluble HLA-G5 was the topic in our research, the recent investigations was used to focus exclusively in vitro, but there was differenc in the microenvironment of in vitro and in vivo. the results would provide direct evidence for the clinical or the further rsearch.HLA-G5 in the transplant recipient was detected by ELISA , Western blot and FCM. 30 cases of healthy volunteers, 50 cases liver or renal transplantrecipients with stable graft function at 3 months after operation were selected to detect the expression of HLA-G5 in Peripheral serum. HLA-G5 expression of Peripheral serum was compared in 50 cases of liver transplantation and 60 cases of kidney transplantation recipients including rejection and non-rejection. Relationship of the expression of HLA-G5 and transplantation time was observed in 33 cases of liver and kidney transplantation recipients. At the same time, the relationship of different immune suppression and the expression of HLA-G5 were studied in 4 groups' base on different immunosuppressive therapy. The expression of HLA-G5 in 1 case of heart transplantation was observed on dynamic stateDuring 32 weeks. The dependability of the expression of HLA-G5 and Fasl was detected in 6 cases of liver transplantation and 7 cases of kidney transplantation recipients on 8 weeks post transplantation. Dissolubility HLA-G was detected by ELISA and Western blot. All data were statistical analyzed with SPSS 11.0; T test was applied in the comparison of each group.Except for 2 cases of the volunteers with 8ng/ml, 9ng/ml HLA-G5 in peripheral blood, the others (93.3%) were negative. Compared to the liver or renal transplant recipients with stable graft function at 3 months after the operation, the differences is significant (t=2.6834, P<0.01 and t=2.6904, P<0.01). There is significant differences between liver and renal recipients (t=2.4772, P<0.05) also. One of the 16 liver recipients, in which HLA-G was positive, got acute rejection(AR); But for the 34 cases HLA-G negative ones, 10cases got AR(P<0.05). In liver recipients, one got chronic rejection(CR) among the HLA-G positive ones, 13 in HLA-G negative ones (P<0.05) . In renal recipients, 12 cases were HLA-G positive, 48 cases were negative. One of the positive ones got AR, 19 cases for the negative ones (P<0.05). There wasn't CR in HLA-G positive ones but 16 case in negative ones. The difference was significant(P<0.05 ) . There is significant difference between pre- and post-operation on HLA-G expression for liver, renal and heart graft recipients, the expression of HLA-G began to increase at 4 weeks after the operation. The immunosuppressant had no effects on HLA-G expression. The expression of Fasl in HLA-G positive ones was 4.56%, 0.84% in HLA-G negative ones (P<0.01) .The results show that The HLA-G5 assay in healthy volunteers indicated that the expression of HLA-G5 in peripheral blood is low or not under circumstance, HLA-G5 is correlated closely with transplantation. First, in the presence of stable allograft ,the expression of HLA-G5 in liver transplant recipients is higher than in renal graft recipients, the expressed rates of rejection in liver or renal graft recipients is higher than the recipients with stable graft . as a result, the expression of HLA-G5 is positively related to the stable function of liver or renal grafts, the kinetic monitoring of HLA-G5 in cardiac graft recipients indicates that the consistent expression of HLA-G5 probably does good to the survival of cardiac graft. HLA-G is positively related to Fas ligand, it inhibit the Fas-ligand via binding the surface of T cells, Fasl induce the apoptosis of T...