Experience with alternate-day thymoglobulin induction in pancreas transplantation with portal-enteric drainage

The survival advantage of pancreas after kidney transplant

Patient survival after pancreas after kidney transplant (PAK) has been reported to be inferior to patient survival after simultaneous pancreas-kidney transplant (SPK). The authors examine national data to further explore allograft (kidney and pancreas) and patient survival after PAK. Kaplan-Meier and Cox proportional hazard models were used to analyze Organ Procurement and Transplantation Network data from 1995 to 2010. The analysis compared PAK and SPK candidates and recipients. Kaplan-Meier analysis results showed that PAK after either a living or a deceased donor kidney transplant is associated with increased kidney graft survival compared with recipients with type 1 diabetes who received only a kidney. The best kidney allograft survival was for patients who received a living donor kidney followed by PAK. Receiving a living donor kidney was associated with increased pancreas allograft survival compared with receiving a deceased donor kidney. PAK transplant recipients who receive both organs have a survival advantage compared with uremic candidates who receive neither (SPK waitlist). Compared with uremic diabetic waitlist patients, SPK and PAK recipients showed similar overall patient survival. Successful PAK offers a survival advantage compared with receiving neither a kidney nor a pancreas transplant. These data also suggest that receiving a pancreas (after kidney) transplant may have a protective effect on the kidney allograft.

Immunosuppressants in Organ Transplantation

The goal of immunosuppressive therapy post-transplantation in pediatric renal transplant recipients is to prevent acute and chronic rejection while minimizing drug side effects. Most therapies alter immune response mechanisms but are not immunologically specific, and a careful balance is required to find the dose that prevents rejection of the graft while minimizing the risks of overimmunosuppression leading to infection and cancer. While this chapter because of space constraints focuses on immunosuppressive therapy in pediatric renal transplant recipients, many aspects can be applied on pediatric recipients of other solid organ transplants such as the liver and heart. The major maintenance immunosuppressive agents currently used in various combination regimens are tacrolimus, cyclosporine, mycophenolate mofetil, azathioprine, everolimus, sirolimus, and glucocorticoids (steroids). Although data from adult renal transplantation trials are used to help guide management decisions in pediatric patients, immunosuppressive therapy in pediatric renal transplant recipients often must be modified because of the unique dosage requirements and clinical effects of these agents in children, including their impact on growth and development. The optimal immunosuppressive therapy post-transplant is not established. The goal remains to find the best combination of immunosuppressive agents that optimizes allograft survival by preventing acute rejection while limiting drug toxicities.

Pancreas transplantation: The Wake Forest experience in the new millennium

AIM: To investigate the Wake Forest experience with pancreas transplantation in the new millennium with attention to surgical techniques and immunosuppression.

METHODS: A monocentric, retrospective review of outcomes in simultaneous kidney-pancreas transplant (SKPT) and solitary pancreas transplant (SPT) recipients was performed. All patients underwent pancreas transplantation as intent-to-treat with portal venous and enteric exocrine drainage and received depleting antibody induction; maintenance therapy included tapered steroids or early steroid elimination with mycophenolate and tacrolimus. Recipient selection was based on clinical judgment whether or not the patient exhibited measureable levels of C-peptide.

RESULTS: Over an 11.25 year period, 202 pancreas transplants were performed in 192 patients including 162 SKPTs and 40 SPTs. A total of 186 (92%) were primary and 16 (8%) pancreas retransplants; portal-enteric drainage was performed in 179 cases. A total of 39 pancreas transplants were performed in African American (AA) patients; of the 162 SKPTs, 30 were performed in patients with pretransplant C-peptide levels > 2.0 ng/mL. In addition, from 2005-2008, 46 SKPT patients were enrolled in a prospective study of single dose alemtuzumab vs 3-5 doses of rabbit anti-thymocyte globulin induction therapy. With a mean follow-up of 5.7 in SKPT vs 7.7 years in SPT recipients, overall patient (86% SKPT vs 87% SPT) and kidney (74% SKPT vs 80% SPT) graft survival rates as well as insulin-free rates (both 65%) were similar (P = NS). Although mortality rates were nearly identical in SKPT compared to SPT recipients, patterns and timing of death were different as no early mortality occurred in SPT recipients whereas the rates of mortality following SKPT were 4%, 9% and 12%, at 1-, 3- and 5-years follow-up, respectively (P < 0.05). The primary cause of graft loss in SKPT recipients was death with a functioning graft whereas the major cause of graft loss following SPT was acute and chronic rejection. The overall incidence of acute rejection was 29% in SKPT and 27.5% in SPT recipients (P = NS). Lower rates of acute rejection and major infection were evidenced in SKPT patients receiving alemtuzumab induction therapy. Comparable kidney and pancreas graft survival rates were observed in AA and non-AA recipients despite a higher prevalence of a “type 2 diabetes” phenotype in AA. Results comparable to those achieved in insulinopenic diabetics were found in the transplantation of type 2 diabetics with detectable C-peptide levels.

CONCLUSION: In the new millennium, acceptable medium-term outcomes can be achieved in SKPT and SPTs as nearly 2/3rds of patients are insulin independent following pancreas transplantation.

Current state of renal transplant immunosuppression: Present and future

For kidney transplant recipients, immunosuppression commonly consists of combination treatment with a calcineurin inhibitor, an antiproliferative agent and a corticosteroid. Many medical centers use a sequential immunosuppression regimen where an induction agent, either an anti-thymocyte globulin or interleukin-2 receptor antibody, is given at the time of transplantation to prevent early acute rejection which is then followed by a triple immunosuppressive maintenance regimen. Very low rejection rates have been achieved at many transplant centers using combinations of these agents in a variety of protocols. Yet, a large number of recipients suffer chronic allograft injury and adverse events associated with drug therapy. Regimens designed to limit or eliminate calcineurin inhibitors and/or corticosteroid use are actively being pursued. An ideal immunosuppressive regimen limits toxicity and prolongs the functional life of the graft. This article contains a critical analysis of clinical data on currently available immunosuppressive strategies and an overview of therapeutic moieties in development.

Intraoperative imaging of pancreas transplant allografts using indocyanine green with laser fluorescence

Vascular thrombosis is a cause of allograft loss after pancreas transplantation. We present the use of intraoperative fluorescence imaging with the SPY imaging device (Novadaq Technologies Inc, Toronto, Canada) in two pancreas transplants as a means to assess potency of the vascular anastomoses. Intravenous indocyanine green 2.5 mg/mL was fluoresced with the device to create the intraoperative video sequences, which were recorded. After 60-day follow-up, real-time SPY imaging on these two pancreas transplants did not demonstrate adverse effects on patients or the transplanted allografts. This method of vascular imaging could prove useful in improving short-term graft survival and possibly lowering the thrombosis rates seen with pancreas transplantation. Long-term correlation studies between intraoperative findings and graft survival must be performed to confirm the utility of this imaging method.

Pancreas transplantation: lessons learned from a decade of experience at Wake Forest Baptist Medical Center

This article reviews the outcome of pancreas transplantations in diabetic recipients according to risk factors, surgical techniques, and immunosuppression management that evolved over the course of a decade at Wake Forest Baptist Medical Center. A randomized trial of alemtuzumab versus rabbit anti-thymocyte globulin (rATG) induction in simultaneous kidney-pancreas transplantation (SKPT) at our institution demonstrated lower rates of acute rejection and infection in the alemtuzumab group. Consequently, alemtuzumab induction has been used exclusively in all pancreas transplantations since February 2009. Early steroid elimination has been feasible in the majority of patients. Extensive experience with surveillance pancreas biopsies in solitary pancreas transplantation (SPT) is described. Surveillance pancreas biopsy-directed immunosuppression has contributed to equivalent long-term pancreas graft survival rates in SKPT and SPT recipients at our center, in contrast to recent registry reports of persistently higher rates of immunologic pancreas graft loss in SPT. Furthermore, the impact of donor and recipient selection on outcomes is explored. Excellent results have been achieved with older (extended) donors and recipients, in recipients of organs from donation after cardiac death donors managed with extracorporeal support, and in African-American patients. Type 2 diabetics with detectable C-peptide levels have been transplanted successfully with outcomes comparable to those of insulinopenic diabetics. Our experiences are discussed in the light of findings reported in the literature.

Thymoglobulin induction dosing strategies in a low-risk kidney transplant population: three or four days?

The optimal dose and duration of rabbit antithymocyte globulin (rATG) induction has not been defined. Methods. We compared the safety and efficacy of 2 dosing strategies, rATG 1.5 mg/kg for 4 days (n = 59) versus 2 mg/kg for 3 days (n = 59), in a retrospective, cohort study. Results. Two-year rejection-free survival was 95% in each group (P = .983). Renal function and infection rates were similar. The incidence of leucopenia was similar, although the 2 mg/kg group was more likely to be thrombocytopenic on day 2 (4% versus 28%, P = .04). Length of stay tended to be longer for the 1.5 mg/kg group (6.0 ± 3.7 versus 5.1 ± 1.9 days P = .104). A cost savings of $920 per patient for rATG were seen in the 2 mg/kg group (P = .122). Conclusions. Shorter, more intense dosing of rATG is safe and effective. The 3-day dose strategy resulted in a clinically shorter length of stay and may result in cost savings.

Rabbit antithymocyte globulin induction therapy in adult renal transplantation

Rabbit antithymocyte globulin (rATG) and horse antithymocyte globulin (horse ATG) are the polyclonal antithymocyte agents available for use in solid organ transplantation in the United States. Horse ATG is indicated for induction immunosuppression and for treatment of acute rejection episodes after kidney transplantation; rATG is indicated for treatment of acute rejection only. However, rATG is commonly used in clinical practice as an induction immunosuppressive agent, instigating many questions regarding appropriate dosing, tolerability, safety, and efficacy. Available evidence supports the use of rATG as an induction agent in adult renal transplant recipients. The use of this product for induction therapy has been studied in conjunction with a full-dose, triple-therapy maintenance regimen (sequential quadruple immunosuppression) consisting of a calcineurin inhibitor, an antimetabolite, and corticosteroids. Rabbit ATG has a proven safety and efficacy profile both as treatment of acute rejection and as induction therapy in patients undergoing kidney transplantation. The most common adverse events associated with rATG are cytokine release syndrome, thrombocytopenia, and lymphopenia. Results of early studies showed an increased rate of cytomegalovirus disease associated with rATG treatment, but recent studies indicate that routine administration of modern antiviral prophylaxis can reduce this risk. Current practice with rATG is evolving to minimize lifelong exposure to calcineurin inhibitors and corticosteroids.