Banff 2022 pancreas transplantation multidisciplinary report: Refinement of guidelines for T cell-mediated rejection, antibody-mediated rejection and islet pathology. Assessment of duodenal cuff biopsies and noninvasive diagnostic methods

Over 1000 Pancreas Transplants in a Latin American Program

BACKGROUND

Pancreas transplantation (PT) is an effective treatment for patients with type 1 diabetes and end-stage renal disease, or brittle diabetes. However, the total number of PT and high-volume programs has declined worldwide during the past decade. This study aimed to analyze the experience of >1000 PTs in a high-volume Brazilian program.

METHODS

We analyzed 1073 PTs performed from 1996 to 2021, with 593 simultaneous pancreas-kidney (SPK) transplants and 480 solitary PTs, of which 331 were pancreas after kidney (PAK) transplants and 149 PT alone (PTA). Among the 480 solitary PTs, there were 379 primary PAK/PTA and 101 solitary pancreas retransplants (PRTs). Transplants were divided into 3 eras, according to the predominant surgical technique used during each period. The immunosuppression protocol was based on thymoglobulin, tacrolimus, mycophenolate mofetil/sodium, and steroids. Surgical techniques have progressed from systemic-bladder to portal-enteric, portal-duodenal, and presently, systemic-enteric, either to the native duodenum or via duodenojejunostomy.

RESULTS

The overall 1-y patient survival was >90% for primary PTA/PAK and 85% for SPK or PRT. One-year death-censored graft survival was superior for SPK-kidney and SPK-pancreas (97% and 90%, respectively) and 75% for all subgroups of solitary PTs (PAK, PTA, and PRT). There was a significant reduction in cold ischemia time and a decreased rate of pancreatic thrombosis over time, as low as 2%, in SPK recipients.

CONCLUSIONS

During the course of 25 y, our PT program has consistently maintained a high-volume activity and has recently emerged as one of the world's most active programs, conducting >60 PT procedures annually.

Banff 2022 pancreas pathology update: how to make the right diagnosis and decrease inconclusive pathology results

PURPOSE OF REVIEW

The Banff 2022 pancreas transplant pathology update is the most comprehensive to date. It has improved the criteria for T-cell and antibody mediated rejection, recognized other clinicopathological differential diagnoses, and addressed the critically important islet failures. Nevertheless, multidisciplinary discussions during and after the meeting showed a need to enhance the real and perceived value of pancreas transplant biopsies. In particular, the occurrence of clinicopathological discrepancies and/or inconclusive biopsy findings, result in considerable uncertainty in clinical and pathology decision making.

RECENT FINDINGS

The current review expands on the 2022 report by presenting the most common situations leading to an inconclusive diagnosis (Banff "indeterminate" category), a major issue of discussion. The entities discussed herein are: nonspecific infiltrates versus active rejection; residual inflammation after treatment of active rejection; ischemic pancreatitis and peripancreatic reactions in the early posttransplant period; biopsy findings associated with exocrine drainage impairment, and other unusual or nonspecific findings. An algorithm for the evaluation of pancreas allograft biopsies is also presented, that should facilitate the interpretation of morphological findings.

SUMMARY

Systematic integration of essential clinical information with the pathology findings can improve the diagnostic yield of pancreas allograft biopsies and reduce the cases with and "indeterminate" diagnoses.

Rethinking the Diagnosis and Management of Antibody-Mediated Rejection in Multidisciplinary Transplant Meetings: A Global Survey and Banff Working Group Recommendations

INTRODUCTION

The diagnosis of antibody-mediated rejection (AMR) requires input from several transplant professionals. Bringing clinical and laboratory experts together may help standardize care. Yet, little is known about current global practices of multidisciplinary meetings for AMR management.

METHODS

The Banff Antibody-Mediated Injury Working Group approached professional societies worldwide to distribute a survey on the availability, content, participants, perceived value, and barriers to the implementation of multidisciplinary meetings.

RESULTS

Four hundred two transplant professionals from six continents caring for kidney (90.55%), liver (21.14%), pancreas (20.65%), heart (15.17%), and lung (14.18%) transplant recipients participated in the survey, and 302 (75.12%) reported attending multidisciplinary meetings. Multidisciplinary meetings were more prevalent in academic centers, in high- versus low-to-middle-income regions (81.03% and 65.99%, respectively; p < 0.001), and in mid-to-large size transplant programs compared to smaller programs. Perceived value included continued professional development (97.68%) and trainee education (95.70%). AMR was reported to be discussed at these meetings by 217 respondents with case presentations reviewing patient characteristics, histology, and HLA antibody data. A third of the respondents reviewed non-HLA/pathogenic autoantibodies and/or molecular diagnostics, with the latter being more frequently applied in high- versus low-to-middle-income regions (46.71% and 12.31%, respectively; p < 0.001). AMR case presentations allowed diagnosis revision, actionable management plans and were perceived as improving care. The primary barrier to the implementation of multidisciplinary meetings (63.27%) was the unavailability of transplant professionals (e.g., transplant immunologists).

CONCLUSION

Facilitating multidisciplinary meetings through the remote participation of pertinent experts and incentivizing participation through remuneration, protected time, or continued medical education may help standardize AMR diagnosis and harmonize its management.

Pancreas rejection: quieting the storm to preserve graft function

PURPOSE OF REVIEW

Allograft rejection remains enigmatic and elusive following pancreas transplantation. In the absence of early technical pancreas graft failure, pancreas allograft rejection is the major cause of death-censored pancreas graft loss both short- and long-term. Despite this circumstance, there are variations in the diagnosis and treatment of pancreas rejection. In this article, we summarize recent literature, review common practices, and discuss various management algorithms.

RECENT FINDINGS

Although pancreas allograft biopsy is the gold standard for the diagnosis of rejection, not all transplant centers have the capability to perform pancreas allograft biopsy. Some centers depend on clinical or laboratory parameters exclusively or rely on dysfunction or biopsy of a simultaneous kidney allograft as a marker for pancreas allograft rejection. New biomarkers are evolving to assess the risk for rejection and may help to diagnose early rejection. In the future, the use of machine learning algorithms and artificial intelligence may play a role identifying patients at risk and detecting pancreas rejection without performing a pancreas allograft biopsy.

SUMMARY

Despite decades of experience in pancreas transplantation, the diagnosis and management of pancreas rejection remains challenging. Emerging biomarkers and machine learning algorithms are needed to mitigate immunological complications and guide immunosuppression in these patients.

Anti-TNFα as an Adjunctive Therapy in Pancreas and Kidney Transplantation

The rate of early pancreas allograft failure remains high due to thrombosis but also to severity of rejection episodes. We investigated if adjunct anti-TNFα therapy was safe and could improve outcomes after pancreas transplantation. We investigated all pancreas transplants performed in our institution between 2010 and 2022. Etanercept, an anti TNFα therapy, was added to our standard immunosuppressive regimen since 2017 after approval from our institutional human ethics committee. Pancreas survival, rejection episodes, as well as infectious complications were analyzed. A total of 236 pancreas transplants were included, among whom 87 received Etanercept for induction. In multivariable analysis, after adjustment on confounding variables, pancreas survival did not differ between groups (HR = 0.92, CI 95% = 0.48; 1.73, p = 0.79). However, patients receiving Etanercept presented a significantly lower occurrence of pancreas rejection in multivariate analysis (HR = 0.36, CI 95% = 0.14; 0.95, p = 0.04). Patients receiving Etanercept did not experienced a higher risk of bacterial, fungal, CMV nor BK virus infections compared to the non-treated group. The use of anti-TNFα after pancreas transplantation was safe and did not increase infectious complications. Despite a similar rate of thrombosis, anti-TNFα significantly reduced pancreatic rejection, thus supporting its use among pancreas transplant recipients.

Gene expression-based molecular scoring of pancreas transplant rejection for a quantitative assessment of rejection severity and resistance to treatment

Pancreas transplantation improves glycemic control and mortality in patients with diabetes but requires aggressive immunosuppression to control the alloimmune and autoimmune response. Recent developments in "omics" methods have provided gene transcript-based biomarkers for organ transplant rejection. The tissue Common Response Module (tCRM) score is developed to identify the severity of rejection in kidney, heart, liver, and lung transplants. Still, it has not yet been validated in pancreas transplants (PT). We evaluated the tCRM score's relevance in PT and additional markers of acute cellular rejection (ACR) for PT. An analysis of 51 pancreas biopsies with ACR identified 37 genes and 56 genes significantly upregulated in the case of grade 3 and grade 2 ACR, respectively (P < .05). Significant differences were seen with higher grades of rejection among several transcripts. Of the 22 genes differentially expressed in grade 3 ACR, 18 were also differentially expressed in grade 2 ACR. The rejection signal was attributable to activated leukocytes' infiltration. Significantly higher tCRM scores were found in grade 3 ACR (P = .007) and grade 2 ACR (P = .004), compared to normal samples. The tCRM score was able to distinguish treatment-resistant cases from those successfully treated for rejection.

Management of Failing Kidney and Pancreas Transplantations

Survival rates for allografts have improved over the last 2 decades, yet failing allografts remains a challenge in the field of transplant. The risks of mortality and morbidity associated with failed allografts are compounded by infectious complications and metabolic abnormalities, emphasizing the need for a standardized approach to management. Management of failing allografts lacks consensus, highlighting the need for unified protocols to guide treatment protocols and minimize risks with postdialysis initiation. The decision to wean off immunosuppression depends on various factors, including living donor availability and infectious risks, necessitating improved coordination of care and a standard guideline. Treatment of failed pancreas focuses on glycemic control, with insulin as the mainstay, while considering surgical interventions such as graft pancreatectomy in advanced symptomatic cases. Navigating the complexities of failed allograft management demands a multidisciplinary approach and standardized stepwise protocol. Addressing the gaps in management plans for failing allografts and employing a systematic approach to transplant decisions will enhance patient outcomes and facilitate informed decision-making.

Transplant nephropathology: Wherefrom, wherein, and whereto

Renal pathology is a relatively recent entry in nephrology. While diseases of the kidney are old, their study began in the 19th century with the report of Richard Bright of the lesions of end-stage kidney disease. Its easy diagnosis from albuminuria soon elevated Bright's nephritis into a leading cause of death. The transformative events in the care of these cases were renal replacement therapy that converted a fatal into a chronic disease, and kidney biopsy that allowed study of the course and pathogenesis of kidney disease. Apart from its fundamental contributions to clinical nephrology, biopsy of renal allografts became an integral component of the evaluation and care of kidney transplant recipients. The Banff transplant pathology conferences launched in 1991 led to developing the classification of allograft pathology into an essential element in the evaluation, treatment, and care of allograft recipients with spirit of discovery. That success came at the cost of increasing complexity leading to the recent realization that it may need the refinement of its consensus-based system into a more evidence-based system with graded statements that are easily accessible to the other disciplines involved in the care of transplanted patients. Collaboration with other medical disciplines, allowing public comment on meeting reports, and incorporation of generative artificial intelligence (AI) are important elements of a successful future. The increased pace of innovation brought about by AI will likely allow us to solve the organ shortage soon and require new classifications for xenotransplantation pathology, tissue engineering pathology, and bioartificial organ pathology.

Transplantation: platform to study recurrence of disease

Beyond the direct benefit that a transplanted organ provides to an individual recipient, the study of the transplant process has the potential to create a better understanding of the pathogenesis, etiology, progression and possible therapy for recurrence of disease after transplantation while at the same time providing insight into the original disease. Specific examples of this include: 1) recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation, 2) recurrent autoimmunity after pancreas transplantation, and 3) recurrence of disease after orthotopic liver transplantation (OLT) for cirrhosis related to progressive steatosis secondary to jejuno-ileal bypass (JIB) surgery. Our team has been studying these phenomena and their immunologic underpinnings, and we suggest that expanding the concept to other pathologic processes and/or transplanted organs that harbor the risk for recurrent disease may provide novel insight into the pathogenesis of a host of other disease processes that lead to organ failure.