Meeting Report of the XIV International Small Bowel Transplant Symposium: Summary of Presentations, Workshops, and Debates From a Comprehensive Meeting on Intestinal Failure, Rehabilitation, and Transplantation, Buenos Aires, Argentina, June 10-13, 2015

Immune cell profiling in intestinal transplantation

Since the first published case study of human intestinal transplantation in 1967, there have been significant studies of intestinal transplant immunology in both animal models and humans. An improved understanding of the profiles of different immune cell subsets is critical for understanding their contributions to graft outcomes. While different studies have focused on the contribution of one or a few subsets to intestinal transplant, no study has integrated these data for a comprehensive overview of immune dynamics after intestinal transplant. Here, we provide a systematic review of the literature on different immune subsets and discuss their roles in intestinal transplant outcomes on multiple levels, focusing on chimerism and graft immune reconstitution, clonal alloreactivity, and cell phenotype. In Sections 1, 2 and 3, we lay out a shared framework for understanding intestinal transplant, focusing on the mechanisms of rejection or tolerance in the context of mucosal immunology and illustrate the unique role of the bidirectional graft-versus-host (GvH) and host-versus-graft (HvG) alloresponse. In Sections 4, 5 and 6, we further expand upon these concepts as we discuss the contribution of different cell subsets to intestinal transplant. An improved understanding of intestinal transplantation immunology will bring us closer to maximizing the potential of this important treatment.

First Registry of Adult Patients with Chronic Intestinal Failure due to Short Bowel Syndrome in Argentina, the RESTORE Project

BACKGROUND

Short-bowel syndrome (SBS) is considered a low prevalence disease. In Argentina, no registries are available on chronic intestinal failure (CIF) and SBS. This project was designed as the first national registry to report adult patients with this disease.

METHODS

A prospective multicenter observational registry was created including adult patients with CIF/SBS from 8/12 approved centers. Demographics, clinical characteristics, nutritional assessment, home-parenteral-nutrition (HPN) management plus complications, surgeries performed, medical treatment, overall survival, and freedom from HPN survival were analyzed.

RESULTS

Of the 61 enrolled patients, 56 with available follow up data were analyzed. At enrollment, the mean intestinal length was 59.5±47.3cms; the anatomy was: type 1 (n=41), type 2 (n=10), and type 3 (n=5). At the end of the interim analysis, anatomy changed to type 1 in 31, type 2 in 17, and type 3 in 8 patients. The overall mean time on HPN before enrollment was 33.5±56.2 months. Autologous gastrointestinal-reconstruction surgery was performed before enrollment on 21 patients, and afterward on 11. Nine patients (16.1%) were weaned-off HPN with standard medical-nutritional treatment; 12 patients received enterohormones, and 2 of them suspended HPN; 1 was considered a transplant candidate. In 23.7±14.5 months, 11 out of 56 patients discontinued HPN; Kaplan-Meier freedom from HPN survival was 28.9%. The number of cases collected represented 19.6 new adult CIF/SBS patients/year.

CONCLUSIONS

The RESTORE project allowed us to know the incidence, the current medical and surgical management of this pathology, as well as its outcome and complications related with the therapeutic approach currently available.

CLINICAL RELEVANCY STATEMENT

RESTORE is the first ongoing prospective, observational, epidemiological, multicenter registry of adult patients with chronic intestinal failure (CIF) due to short bowel syndrome (SBS) in Argentina. The interim analysis enabled an estimate of the incidence of adult CIF/SBS of 19.6 new adult CIF/SBS patients/year in our country and would serve for a better understanding of the current care provided, the manner to continue improving that condition, the current treatment outcomes, and a more accurate definition of the national needs. This article is protected by copyright. All rights reserved.

Chronic Rejection After Intestinal Transplant: Where Are We in Order to Avert It?

Chronic rejection affects the long-term survival of all solid organ transplants and, among intestinal allografts, occurs in up to 10% of the recipients. The insidious clinical evolution of the chronic allograft enteropathy, the absence of noninvasive biomarkers, and the late endoscopic findings delay its diagnosis. No pharmacological approach has been proven effective, and allograft removal nowadays still represents the only available therapy. The inclusion of the liver in the visceral allograft appears to be the only intervention affecting the development of chronic rejection, as revealed by large-center studies and registry reports. A significant body of evidence emerged from the experimental setting and provided essential knowledge on the complex mechanisms behind the development of chronic allograft enteropathy. More recently, donor-specific antibodies have been suggested as an early, key element in the natural history of chronic allograft enteropathy and several novel approaches, tackling the antibody-mediated graft injury, have gained acceptance in clinical settings and are believed to impact on chronic rejection. The inclusion of a liver allograft is advocated when re-transplanting a sensitized recipient, due to its protective effect against humoral immunity. Multicenter trials are required to understand and tackle chronic rejection, and find the therapeutic answer to this clinical dilemma.