Objective To discuss the procedure and the clinical effects of a vena cava drainage bypass through the donor's iliac artery during a simultaneous pancreas-kidney（SPK）transplantation. Methods In Organ Transplantation Center of Tianjin First Center Hospital，between January 2009 and December 2011，we performed a SPK transplantation with a vena cava drainage bypass through the donor's iliac artery for 35 patients with diabetes mellitus that was complicated with end-stage renal disease. The pancreatic allograft artery and renal allograft artery were anastomosed with the donor's external iliac artery and internal iliac artery，respectively. Then， the donors'common iliac artery was sewn to the recipient's external iliac artery. The donor's pancreatic vein wasanastomosed with the recipient's inferior vena cava for drainage. The donor's duodenum was side-to-side anastomosed to the recipients' ileum. The patients' general results，surgical complications，and long-term complications was observed，and follow-up period was 35-58 months. Results All of the renal and pancreatic allografts wererestored to their normal functions within 1 week after operation. The length of hospitalization ranged from 10 to 33 days（average 22 days）. The length of intensive care unit stay ranged from 1 to 4 days（average 2.4 days）. 33 patients were administered with combined immunosuppression therapy with tacrolimus（FK506） + mycophenolatemofetil（MMF）+ prednisone（Pred）. 2 patients wereprescribed combined immunosuppression therapy with cyclosporin A + MMF + Pred. In all patients，there were three cases of DGF，and none of rejection. At the time of discharge，the patients' average serum creatinine level was 78 μmol/L，with average fasting glucose level of 4.4 mmol/L，and their average glycated hemoglobin percentage of 4.3%. The following post-operative complications were observed ：two cases of anastomotic bleeding between the donor duodenum and the recipient ileum，four cases of poor wound healing，four cases of post-operative abdominal infections，five cases of pulmonary infections，onecase of urinary tract infection，two cases of cytomegalovirus infections，and one case of FK506 related demyelinatingdisease. Three cases underwent re-operations. One case underwent adhesion lysis for adhesive intestinal obstruction.One case underwent pancreatectomy for diffuse pancreatic thrombosis and suffered post-operative abdominal infectionand wound dehiscence which were healed with debridement suture operation. One case underwent nephrectomy for renal graft rupture and received second kidney transplantation 5 months later. The re-operation rate was 8.6%. Allpatients were followed up for 32-58 months. Six months after the surgery，the patients' average serum creatinine levelwas 82 μmol/L，with average fasting glucose level of 4.8 mmol/L，and mean glycated hemoglobin percentage of 4.5%. All of the patients survived except one case died of pulmonary infection 4 months after operation. One year survival rates of recipients，pancreatic allograft，renal allograft were 97.1%，94.2%，94.2%，respectively. Conclusion SPK transplantation with a vena cava drainage bypass through the donor's iliac artery is a simple procedure that leads to less severe trauma than traditional methods and is also appropriate for a wider range of recipients. Moreover，one side of the iliac artery is unaffected，which is useful for the second kidney transplantation in a recipient，if this procedure is later needed. The number of post-operative complications that needed surgical interventions were also significantly

reduced compared to those associated with traditional methods.

Objective To assess the impacts of sirolimus（SRL）and tacrolimus（TAC）on immune conditionin renal transplant recipients，in order to find the optimal immunosuppressive regimens. Methods According to the different immunosuppressive regimens，18 living donor renal transplant recipients with stable renal functionwere divided into two groups ：SRL group（n ＝ 8）on SRL + mycophenolate mofetil（MMF）+ prednisone（Pred）and TAC group（n ＝ 10）on TAC + MMF + Pred. All the patients received the immunosuppressive regimens for atleast one year. The living donors were chosen as the blank control. All the subjects of the 3 groups were examined for the proportion of Regulatory T（Treg）cells（CD4+CD25+Foxp3+）and Regulatory B（Breg）cells（CD19+CD5+CD1d+） in their peripheral blood mononuclear cells（PBMCs）by flow cytometry. After stimulation by the corresponding donor's PBMCs，the recipient's PBMCs were measured through the production of interferon-γ（IFN-γ）and interleukin-10（IL-10）of the recipient's PBMCs of SRL group and TAC group were measured by enzyme-linkedimmunospot assay（ELISPOT）. Results The proportion of CD4+ CD25+ Foxp3+ Treg in the SRL group，TACgroup and blank control group were（6.68±0.42）％，（3.59±0.47）％ and（6.59±0.36）％，respectively. The ratio of the SRL group and blank control group were significantly higher than that of the TAC group（both P ＜ 0.05），and there was no statistically significant difference between the SRL group and blank control group（P ＞ 0.05）. Theproportion of CD19+CD5+CD1d+ B cells in the SRL group，TAC group and blank control group were（16.43±3.56）%，（13.09±1.64）％ and（16.58±1.31）％，respectively. There were no statistically significant differences among thethree groups（all P ＞ 0.05）. The frequency of the cellsproducing IFN-γ in the SRL group and TAC group detectedby ELISPOT were（117.00±21.54）/ 500 000 and（126.00±24.08）/ 500 000，without significant difference （P ＞ 0.05）. The frequency of the cellsproducing IL-10 in the SRL group and TAC group were（347.00±55.29）/ 500 000 and（249.00±58.97）/ 500 000，without significant difference（P ＞ 0.05）. Conclusion The regimenbased on SRL shows no effect on the percentage of Treg of PBMC in long-term renal transplant recipients，however， the regimen based on TAC reduces the percentages. Meanwhile，both the regimens have no impact on the proportionof Breg in the peripheral CD19+ B cells and on the donor-specific immune reaction.