Changes in T lymphocytic subpopulations and expression of co-stimulatory molecules after combined liver and kidney transplantation

Abstract

Objective To investigate the protection of the kidney from rejection by the liver in combined liver and kidney transplantation (CLKT).Methods Three groups were set up in this study:CLKT group,kidney transplantation (OKT) group and control group.Wistar and male SD rats were used as donors and SD rats as recipients in all groups.The graft specimens were harvested at 5th day postoperatively.They were examined histologically after sectioning and staining.Acute rejection was diagnosed according to the Banff 97 classification,and scored according to the method stated by Watanabe.The semiquantitative scores were compared between CLKT and OKT groups.Fluorescein-labeled monoclonal antibodies and flow cytometry were employed to determine the T-cell subsets and the expression of CD28 and CD152 in venous blood T cells among CLKT,OKT and control groups.Results The semiquantitative scores in CLKT group and OKT group were (1.43 ± 0.53) and (4.14 ± 0.69),respectively (P ＜ 0.01).The total number of CD3+ T lymphocytes in CLKT group,OKT group and contr group was (71.31 ±14.21)％,(72.63 ± 14.96)％ and (68.30 ± 12.40)％ respectively (P ＞0.05),but there were significant difference in the total number of CD4 + CD3 + T lymphocytes among the three groups:that in OKT group was the greatest,followed by CLKT group,and lowest in control group (P ＜ 0.05).There was no significance difference in CD8 + CD3 + T lymphocytes between CLKT group and control group (P ＞ 0.05),but the number of CD8 + CD3 + T lymphocytes was significantly reduced in CLKT group as compared with OKT group (P ＜ 0.05).The CD4 +/CD8 + ratio was highest in OKT group,followed by CLKT group,and lowest in control group (P ＜ 0.05).The CD28％ was highest in OKT group,followed by CLKT group,and lowest in control group (P ＜ 0.05).The CD152％ was highest in CLKT group,followed by OKT group,and lowest in control group (P ＜ 0.05).Conclusion Liver graft had protective effects on kidney graft in CLKT,and decreased its rejection intensity.The maturity and activation of T lymphocytes were inhibited in CLKT,and CLKT could also inhibit the expression of positive co-stimulatory molecule CD28,and promote the expression of negative co-stimulatory molecule CD152,which contributed to the protective effects of the liver graft on the kidney graft. Key words: Combined liver and kidney transplantation; Acute rejective reaction; T lymphocyte; Co-stimulatory molecules