Pancreas transplantation in crossmatch-positive recipients

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.

Guidelines for the diagnosis of antibody-mediated rejection in pancreas allografts-updated Banff grading schema

The first Banff proposal for the diagnosis of pancreas rejection (Am J Transplant 2008; 8: 237) dealt primarily with the diagnosis of acute T-cell-mediated rejection (ACMR), while only tentatively addressing issues pertaining to antibody-mediated rejection (AMR). This document presents comprehensive guidelines for the diagnosis of AMR, first proposed at the 10th Banff Conference on Allograft Pathology and refined by a broad-based multidisciplinary panel. Pancreatic AMR is best identified by a combination of serological and immunohistopathological findings consisting of (i) identification of circulating donor-specific antibodies, and histopathological data including (ii) morphological evidence of microvascular tissue injury and (iii) C4d staining in interacinar capillaries. Acute AMR is diagnosed conclusively if these three elements are present, whereas a diagnosis of suspicious for AMR is rendered if only two elements are identified. The identification of only one diagnostic element is not sufficient for the diagnosis of AMR but should prompt heightened clinical vigilance. AMR and ACMR may coexist, and should be recognized and graded independently. This proposal is based on our current knowledge of the pathogenesis of pancreas rejection and currently available tools for diagnosis. A systematized clinicopathological approach to AMR is essential for the development and assessment of much needed therapeutic interventions.

Current status of pancreas transplantation

Pancreas transplantation has emerged as the treatment of choice for patients with end-stage diabetes mellitus. Over the last four decades, many improvements have been made in the surgical techniques and immunosuppressive regimens, which contributed to increased number of indications and improved allograft survival. Pancreas transplantation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure with a relatively higher complication rate, and lifelong immunosuppression. Therefore, efforts to develop more minimally invasive techniques for endocrine replacement therapy such as islet transplantation have been in progress. This article summarizes the current understanding of pancreas transplantation-associated indications, donor selection, surgical techniques, immunosuppression, and rejection.

Pancreas transplantation

Since the introduction of pancreas transplantation more than 40 years ago, efforts to develop more minimally invasive techniques for endocrine replacement therapy have been in progress, yet this surgical procedure still remains the treatment of choice for diabetic patients with end-stage renal failure. Many improvements have been made in the surgical techniques and immunosuppressive regimens, both of which have contributed to an increasing number of indications for pancreas transplantation. This operation can be justified on the basis that patients replace daily injections of insulin with an improved quality of life but at the expense of a major surgical procedure and lifelong immunosuppression. The various indications, categories, and outcomes of patients having a pancreas transplant are discussed, particularly with reference to the effect on long-term diabetic complications.

Preformed cytotoxic antibodies in potential allograft recipients: recent data

Presensitization to donor human leukocyte antigen (HLA) remains a major barrier to cell and organ transplantation, thereby contributing to patient mortality. The risks associated with transplantation in the presence of preformed antidonor HLA antibodies range from hyperacute rejection and increased frequency and severity of rejection to no appreciable effect on transplant outcome. Recent evidence has emphasized the importance of immunologic history, anti-HLA antibody class and titer, and differential organ susceptibility to antibody-mediated damage to explain differences in risk for antibody-mediated rejection. Furthermore, in studies of endothelial cells, ligation of class I molecules by subsaturating concentrations of antibodies stimulated expression of cell survival proteins, raising the possibility that, under certain conditions, antibodies promote graft accommodation providing a mechanism for the endothelium to resist immune and inflammatory damage. The discovery of capillary-bound C4d as a robust diagnostic marker for antibody-mediated rejection, coupled with the development of solid-phase assays for the identification of HLA-specific antibodies, has enhanced our ability to detect antibody-mediated rejection and interpret cross-match results. With new diagnostic tools and immunosuppression regimens such as plasmapheresis and intravenous immunoglobulin therapy targeting the humoral immune response, it is time for a concerted effort to reassess the role of alloantibodies in acute and chronic rejection.