Heart transplantation across preformed donor-specific antibody barriers using a perioperative desensitization protocol

Summary of a Consensus Conference on the Management of Highly Sensitized Multiorgan Transplant Candidates

The number of highly sensitized patients in need of a multiorgan transplant is increasing. Criteria informing their transplant candidacy, approaches to management on the waitlist, and protocols related to alloantibody monitoring vary widely. We convened a consensus conference to discuss these different practices in the United States and the United Kingdom and to review the contemporary outcomes of these challenging cases. A detailed analysis of the data regarding the liver allografts' immunoprotective effect on simultaneously transplanted other organs was also completed, and the prospect of the use of liver allografts primarily to facilitate transplantation of highly sensitized patients in need of other organs was discussed. The ethical and allocation-related issues about such prospect were debated with a goal to standardize the approach and provide an evidence-based pathway for pre-, peri-, and post-transplantation management for the highly sensitized multiorgan transplantation candidate.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2022 Part II: Cardiac Transplantation

These highlights focus on research published in the year 2022 and is divided into preoperative, intraoperative, and postoperative sections. The preoperative section includes research on the assessment and optimization of candidates for heart transplantation; donor optimization and the use of extended donors; organ protection systems; donation after circulatory death allografts; recipient factors including cannabis use, sex, race, and comorbidities such as obesity, diabetes mellitus, and peripartum cardiomyopathy; the effects of the 2018 heart allocation policy change on waitlist and postoperative mortality; updates on heart transplantation in patients with coronavirus disease 2019; in pediatric patients; and those who require a bridge to transplant. The intraoperative section includes the use of a multidisciplinary team, a proposed transfusion algorithm, bench surgery on the allograft, and size matching. The postoperative section focuses on the research on the development and management of tricuspid regurgitation, echocardiography, arrhythmia management, and, finally, xenotransplantation.

Targeting inerleukin-6 for renoprotection

Sterile inflammation has been increasingly recognized as a hallmark of non-infectious kidney diseases. Induction of pro-inflammatory cytokines in injured kidney tissue promotes infiltration of immune cells serving to clear cell debris and facilitate tissue repair. However, excessive or prolonged inflammatory response has been associated with immune-mediated tissue damage, nephron loss, and development of renal fibrosis. Interleukin 6 (IL-6) is a cytokine with pleiotropic effects including a major role in inflammation. IL-6 signals either via membrane-bound (classic signaling) or soluble receptor forms (trans-signaling) thus affecting distinct cell types and eliciting various metabolic, cytoprotective, or pro-inflammatory reactions. Antibodies neutralizing IL-6 or its receptor have been developed for therapy of autoimmune and chronic non-renal inflammatory diseases. Small molecule inhibitors of Janus kinases acting downstream of the IL-6 receptor, as well as recombinant soluble glycoprotein 130 variants suppressing the IL-6 trans-signaling add to the available therapeutic options. Animal data and accumulating clinical experience strongly suggest that suppression of IL-6 signaling pathways bears therapeutic potential in acute and chronic kidney diseases. The present work analyses the renoprotective potential of clinically relevant IL-6 signaling inhibitors in acute kidney injury, chronic kidney disease, and kidney transplantation with focus on current achievements and future prospects.

Single center experience with ABO-incompatible and ABO-compatible pediatric heart transplantation

Introduction

The aim of this study was to analyze the results after pediatric heart transplantation (pHTx) at our single center differentiating between ABO-incompatible (ABOi) and -compatible (ABOc) procedures.

Methods and patients

We retrospectively analyzed outcomes of ABO-incompatible HTx procedures performed at our center and compared the data to ABO-compatible HTx of the same era. Eighteen children (<17 months) underwent pediatric HTx and seven of them underwent ABO-incompatible HTx between 2003 and 2015.

Results

Mechanical circulatory support as bridge to transplant was necessary in 3/7 patients before ABO-incompatible HTx and in 3/11 patients before ABO-compatible HTx. Mean waiting time on the list was 36 ± 30 days for ABO-incompatible HTx and 86 ± 65 days for ABO-compatible HTx. The 5-years re-transplant free survival was 86% following ABO-incompatible and 91% after ABO-compatible. In the cohort undergoing ABO-incompatible HTx, 2 patients showed an acute cellular rejection, while early graft failure was not observed. In the cohort undergoing ABOcompatible HTx, acute cellular rejection was observed in 9/11 patients, with early graft failure occurring in nine and CVP in two. A total of ten children were listed for ABO-incompatible HTx after 2015; however, all ten underwent an ABO-compatible transplantation.

Discussion

This study adds much needed information to the literature on ABOi-HTx by showing with a retrospective single center analysis that it is safe and leads to shorter waiting times. We conclude that strategies for ABOi-HTx should be elaborated further, potentially allowing more timely transplantation and thereby preventing waiting list complications such as the need for mechanical circulatory support and even death.

Modern advances in heart transplantation

Heart transplantation (HTx) is the only definitive therapy for patients with end stage heart disease. With the increasing global prevalence of heart failure, the demand for HTx has continued to grow and outpace supply. In this paper, we will review advances in the field of HTx along the clinical journey of a HTx recipient. Starting with the sensitized patient, we discuss current methods to define sensitization, and assays to help identify clinically relevant anti-HLA antibodies. Desensitization strategies targeting all levels of the adaptive immune system are discussed with emphasis on novel techniques such as anti-CD 38 blockade and use of the Immunoglobulin G-Degrading Enzyme of Streptococcus Pyogenes. We next discuss donor procurement and the resurgence of donation after circulatory death as a viable strategy to significantly and safely increase the donor pool. Post-transplant, we evaluate non-invasive surveillance techniques including gene expression profiling and donor-derived cell-free DNA. Last, we discuss the ground-breaking developments in the field of xenotransplantation.

Impact of donor-specific anti-HLA antibody on cardiac hemodynamics and graft function 3 years after pediatric heart transplantation: First results from the CTOTC-09 multi-institutional study

The aim of this study (CTOTC-09) was to assess the impact of "preformed" (at transplant) donor-specific anti-HLA antibody (DSA) and first year newly detected DSA (ndDSA) on allograft function at 3 years after pediatric heart transplantation (PHTx). We enrolled children listed at 9 North American centers. The primary end point was pulmonary capillary wedge pressure (PCWP) at 3 years posttransplant. Of 407 enrolled subjects, 370 achieved PHTx (mean age, 7.7 years; 57% male). Pre-PHTx sensitization status was nonsensitized (n = 163, 44%), sensitized/no DSA (n = 115, 31%), sensitized/DSA (n = 87, 24%), and insufficient DSA data (n = 5, 1%); 131 (35%) subjects developed ndDSA. Subjects with any DSA had comparable PCWP at 3 years to those with no DSA. There were also no significant differences overall between the 2 groups for other invasive hemodynamic measurements, systolic graft function by echocardiography, and serum brain natriuretic peptide concentration. However, in the multivariable analysis, persistent first-year DSA was a risk factor for 3-year abnormal graft function. Graft and patient survival did not differ between groups. In summary, overall, DSA status was not associated with worse allograft function or inferior patient and graft survival at 3 years, but persistent first-year DSA was a risk factor for late graft dysfunction.

Lung transplantation despite preformed donor-specific antihuman leukocyte antigen antibodies: a 9-year single-center experience

Pretransplant allosensitization to human leukocyte antigens (HLA) increases the recipient's waiting list time and mortality in lung transplantation. Rather than waiting for crossmatch-negative donors, since 2013, recipients with preformed donor-specific antiHLA antibodies (pfDSA) have been managed with repeated IgA- and IgM-enriched intravenous immunoglobulin (IgGAM) infusions, usually in combination with plasmapheresis before IgGAM and a single dose of antiCD20 antibody. This retrospective study presents our 9-year experience with patients transplanted with pfDSA. Records of patients transplanted between February 2013 and May 2022 were reviewed. Outcomes were compared between patients with pfDSA and those without any de novo donor-specific antiHLA antibodies. The median follow-up time was 50 months. Of the 1,043 patients who had undergone lung transplantation, 758 (72.7%) did not develop any early donor-specific antiHLA antibodies, and 62 (5.9%) patients exhibited pfDSA. Among the 52 (84%) patients who completed treatment, pfDSA was cleared in 38 (73%). In pfDSA vs control patients and at 8-year follow-up, respectively, graft survival (%) was 75 vs 65 (P = .493) and freedom from chronic lung allograft dysfunction (%) was 63 vs 65 (P = .525). In lung transplantation, crossing the preformed HLA-antibody barrier is safe using a treatment protocol based on IgGAM. Patients with pfDSA have a good 8-year graft survival rate and freedom from chronic lung allograft dysfunction, similar to control patients.

Targeting IL-6 to prevent cardiac allograft rejection

Outcomes following heart transplantation remain suboptimal with acute and chronic rejection being major contributors to poor long-term survival. IL-6 is increasingly recognized as a critical pro-inflammatory cytokine involved in allograft injury and has been shown to play a key role in regulating the inflammatory and alloimmune responses following heart transplantation. Therapies that inhibit IL-6 signaling have emerged as promising strategies to prevent allograft rejection. Here, we review experimental and pre-clinical evidence that supports the potential use of IL-6 signaling blockade to improve outcomes in heart transplant recipients.

Herztransplantation: Perioperative Desensibilisierung bei positiver Kreuzprobe

Herztransplantationen über präformierte donorspezifische HLA-Antikörperbarrieren hinweg beeinträchtigen sowohl das Kurz- als auch Langzeitüberleben. Daher ist es bei Empfängern mit präformierten Anti-HLA-Antikörpern Standardpraxis, auf kreuzproben-negative Spender zu warten. W. Sommer und Kollegen prüften nun alternativ die Möglichkeit, bei Empfängern mit präformierten donorspezifischen Anti-HLA-Antikörpern eine perioperative Desensibilisierung durchzuführen.