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.

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

The Banff pancreas working schema for diagnosis and grading of rejection is widely used for treatment guidance and risk stratification in centers that perform pancreas allograft biopsies. Since the last update, various studies have provided additional insight regarding the application of the schema and enhanced our understanding of additional clinicopathologic entities. This update aims to clarify terminology and lesion description for T cell-mediated and antibody-mediated allograft rejections, in both active and chronic forms. In addition, morphologic and immunohistochemical tools are described to help distinguish rejection from nonrejection pathologies. For the first time, a clinicopathologic approach to islet pathology in the early and late posttransplant periods is discussed. This update also includes a discussion and recommendations on the utilization of endoscopic duodenal donor cuff biopsies as surrogates for pancreas biopsies in various clinical settings. Finally, an analysis and recommendations on the use of donor-derived cell-free DNA for monitoring pancreas graft recipients are provided. This multidisciplinary effort assesses the current role of pancreas allograft biopsies and offers practical guidelines that can be helpful to pancreas transplant practitioners as well as experienced pathologists and pathologists in training.

Incidental appendicectomy in pancreas transplantation: A single-center study

BACKGROUND

Appendicitis in pancreatic transplant recipients can be challenging to diagnose and manage. Incidental appendicectomy (IA) during pancreas transplantation obviates the risk of appendicitis but potentially at the cost of increased operating time or early post-operative complications. This study reviewed the value of IA at a single center.

METHODS

This was a retrospective study of patients who underwent a pancreas transplant in our unit from January 1st, 2012 to December 31st, 2020, with end of follow-up on May 21st, 2023; recipients were grouped by whether or not an IA was performed during pancreas transplantation. Donor, recipient, operative, and graft outcomes were compared between the two groups. Post-transplant complications related to appendiceal pathology (or IA) were recorded and classified.

RESULTS

Two hundred forty-three patients underwent a pancreas transplant; 227 (93%) patients had an appendix in situ at transplantation, and of these 53 (23%) underwent an IA and 174 (77%) did not. There were no statistically significant differences in operative time (p = .06) or hospital stay (p = .50) between the two groups. In the IA cohort, there were no Clavien-Dindo Grade III-V complications relating to the appendicectomy. In those that did not undergo an IA, two patients (1%) subsequently required appendicectomy due to appendicitis. Comparison of pancreatic graft survival showed no statistically significant difference between the groups (p = .44).

CONCLUSIONS

This study suggests that IA is effective at reducing risks of post-transplant appendiceal complications without significantly prolonging inpatient stay or impairing graft survival. These data support the consideration of undertaking an IA for all patients undergoing a pancreas transplant.

First World Consensus Conference on pancreas transplantation: Part II - recommendations

The First World Consensus Conference on Pancreas Transplantation provided 49 jury deliberations regarding the impact of pancreas transplantation on the treatment of diabetic patients, and 110 experts' recommendations for the practice of pancreas transplantation. The main message from this consensus conference is that both simultaneous pancreas-kidney transplantation (SPK) and pancreas transplantation alone can improve long-term patient survival, and all types of pancreas transplantation dramatically improve the quality of life of recipients. Pancreas transplantation may also improve the course of chronic complications of diabetes, depending on their severity. Therefore, the advantages of pancreas transplantation appear to clearly surpass potential disadvantages. Pancreas after kidney transplantation increases the risk of mortality only in the early period after transplantation, but is associated with improved life expectancy thereafter. Additionally, preemptive SPK, when compared to SPK performed in patients undergoing dialysis, appears to be associated with improved outcomes. Time on dialysis has negative prognostic implications in SPK recipients. Increased long-term survival, improvement in the course of diabetic complications, and amelioration of quality of life justify preferential allocation of kidney grafts to SPK recipients. Audience discussions and live voting are available online at the following URL address: http://mediaeventi.unipi.it/category/1st-world-consensus-conference-of-pancreas-transplantation/246.