Objective To explore the inhibition of different immunosuppressive drugs or immunosuppressive combination regiments on the development of de novo donor specific antibodies (dnDSA).Methods We used BABL/c mice and C57BL/6 mice alloimmunized using donor splenocytes for establishing model of producing dnDSA.After that,mice were divided into 10 groups,and were administrated with mycophenolate mofetil (MMF,300 mg· kg-1 · d-1);sirolimus (0.3 mg·kg-1 ·d-1);tacrolimus(0.9 mg· kg-1 · d-1);cyclosporine A (45 mg· kg-1 · d-1);MMF (150 mg· kg-1· d-1) + tacrolimus(0.45 mg · kg-1 · d-1);MMF (150 mg · kg-1 · d-1) + cyclosporine A (22.5 mg·kg-1 ·d-1);MMF (150 mg·kg-1 ·d-1) + sirolimus (0.15 mg·kg-1 ·d-1);sirolimus (0.15 mg· kg-1 · d-1) + tacrolimus (0.45 mg· kg-1 · d-1);sirolimus (0.15 mg· kg-1 · d-1) + cyclosporine A (22.5 mg· kg-1 · d-1);and placebo;respectively.Anti-serum was harvested and tested using flow cytometry.Results (1) Four weeks after sensitization,the dnDSA level in BALB/c and C57BL/6 group was 88.86％ and 25.58％.Comparing with control group(25.33％),there was a significant increase in BALB/c group(89.23％ versus 25.33％;P＜0.001),whereas no change was found in C57BL/6 group (25.58％ versus 25.33％;P =0.259),that we chose BABL/c mice as the model for sensitization.(2)After 4 weeks of sensitization and immunosupression,dnDSA level was 29.31％,46.33％,57.10％ and 66.35％ in MMF,sirolimus,cyclosporine A and tacrolimus monotherapy group respectively.In comparison to sensitization group,dnDSA level in all monotherapy arm reduced significantly.Intra-group analysis found MMF monotherapy had the most effective inhibition of dnDSA production,sirolimus came the second,and tacrolimus and cyelosporine A had equivalent effectiveness.dnDSA level was 31.00％,33.12％,45.18％,44.62％ and 61.60％ in MMF+ sirolimus,MMF+ tacrolimus,MMF+ cyclosporine A,sirolimus + cyclosporine A and sirolimus + tacrolimus combination treatment arm,respectively,which was much lower than that of sensitization group (P＜0.001,P＜0.001,P＜0.001,P＜0.001,P =0.015).MMF + tacrolimus and MMF+ sirolimus combination treatment had comparable effectiveness in dnDSA inhibition,which is greater than that of the rest of three combination.Conclusion Our data show that the effects of single immunosuppressive drugs on the level of dnDSA is MMF＞sirolimus＞cyclosporine A =tacrolimus,and that in combination regimens is MMF + tacrolimus =MMF + sirolimus＞MMF + cyclosporine A =sirolimus + cyclosporine A =sirolimus + tacrolimus.In conclusion,this study demonstrates that MMF+ tacrolimus combination treatment arm can minimize the development of dnDSA.But,this conclusion remains to be confirmed by future clinical studies.

Objective To investigate the effect of birth order on outcomes of renal transplantation from siblings.Method We conducted a retrospective study to examine the immune effect exerted by birth order in kidney transplantation between siblings.227 kidney transplants were included and we stratified the cohort by birth order,old to young parings (group A,104 pairs) and young to old pairings (group B,123 pairs),using old to young parings as reference group.Result During the follow-up period,4 recipients suffered graft failure and 2 died.The survival rate of recipients and grafts was 98％ and 95％,respectively.After adjusting the effect of confounding factors in demography,young to old pairings were found at a higher risk of developing death uncensored graft failure (Hazards ratio,HR =2.77,95％ CI..0.23,33.00),which was not significantly different from group A (P =0.42).And group B had a higher risk of developing death censored graft failure (HR =10.79,95％ CI:0.30-389.43),with no statistically significant difference (P＞0.05).Most rejections occurred in two months after transplantation,and the rejection-free rate in 3 years post-transplantation was 86％.Similarly,no significant difference was detected between the two groups in terms of death censored graft failure,and no benefit of birth order was found in rejection protection (HR =1.266,95％ CI:0.391,4.103,P =0.694).Conclusion Birth order may not be taken into consideration in kidney transplantation between siblings.