Genetic and genomic approaches to the detection of heart transplant rejection

Heart transplant Recipients' perspectives on invasive versus Non-invasive graft failure surveillance Methods

BACKGROUND

Heart transplant recipients must regularly be assessed for graft rejection; however, endomyocardial biopsy (EMB), can be stressful, painful, and inconvenient. AlloMap® is the only commercially available non-invasive test for graft rejection. Current guidelines include AlloMap® testing in low-risk patients OBJECTIVES: To examine the patients' perspective, this study compared patients' experiences of AlloMap® and EMB surveillance at our center.

METHODS

We enrolled consecutive heart transplant recipients who were to undergo routine EMB and AlloMap® testing (on different visits) to quantify their anxiety on the GAD-7 scale and their pain level on the Polyclinic Pain Scale. We assessed paired differences of anxiety and pain within patients according to surveillance method.

RESULTS

We studied 43 participants (median age 60.5[54, 66] years; 35(81%) men; 27(63%) Caucasian). The median GAD-7 scores were 1[0, 4] and 2[0, 5] prior to EMB and AlloMap®, respectively (paired difference: 0[-1, 1],P = 0.323). The median pain scores were 1[0, 1] and 0[0, 0] for EMB and AlloMap®, respectively. Patients experienced less pain with AlloMap® testing compared to EMB (EMB-AlloMap;1[0, 1],P = 0.006). Seven (16%) participants experienced a total of 9 adverse events (pain, bruising, bleeding, swelling) from EMB vs 2(5%) participants who experienced a total of 3 adverse events (pain, bruising) from AlloMap®(P = 0.059).

CONCLUSION

Heart transplant recipients had less pain and fewer adverse events while undergoing graft rejection surveillance with AlloMap® testing compared to EMB. An additional benefit of AlloMap® testing is that it may be performed at home and reduce these high-risk patients' infectious exposures.

Markers of Immune Function in Heart Transplantation: Implications for Immunosuppression and Screening for Rejection

PURPOSE OF REVIEW

Recent developments in high-throughput DNA and RNA sequencing technologies have facilitated the development of noninvasive assays to monitor heart transplant rejection. In this review, we summarize existing assays employed for the surveillance of allograft rejection, as well as promising future directions for such tests in the molecular biology field.

RECENT FINDINGS

The AlloMap genome expression profiling assay remains the only noninvasive test for rejection surveillance and is incorporated into the International Society of Heart and Lung Transplantation guidelines. Other efforts have focused on messenger RNA (mRNA), microRNA (miRNA), and donor-derived cell-free DNA (dd-cfDNA) as potential viable biomarkers. Mitochondrial pathways in allograft necroptosis and inflammation signaling may represent a novel direction for future research endeavors. Although endomyocardial biopsy remains the gold standard, several converging areas of molecular biology could soon yield successful alternative methods of heart transplant rejection monitoring, with the distinct advantage of avoiding procedural complications.

[Pathology of heart transplantation: Where are we now?]

Pathology is still the gold standard for the diagnosis of rejection in heart transplantation. During the last decade, molecular pathology has emerged as a powerful tool for the understanding of the processes implicated in allograft rejection. Transcriptomic analysis of the allograft may also help the pathologist for diagnosis and accurate classification of rejection. This review will describe the recent advances and perspectives of molecular pathology in the field of heart transplantation.

The XVth Banff Conference on Allograft Pathology the Banff Workshop Heart Report: Improving the diagnostic yield from endomyocardial biopsies and Quilty effect revisited

The XVth Banff Conference on Allograft Pathology meeting was held on September 23-27, 2019, in Pittsburgh, Pennsylvania, USA. During this meeting, two main topics in cardiac transplant pathology were addressed: (a) Improvement of endomyocardial biopsy (EMB) accuracy for the diagnosis of rejection and other significant injury patterns, and (b) the orphaned lesion known as Quilty effect or nodular endocardial infiltrates. Molecular technologies have evolved in recent years, deciphering pathophysiology of cardiac rejection. Diagnostically, it is time to integrate the histopathology of EMBs and molecular data. The goal is to incorporate molecular pathology, performed on the same paraffin block as a companion test for histopathology, to yield more accurate and objective EMB interpretation. Application of digital image analysis from hematoxylin and eosin (H&E) stain to multiplex labeling is another means of extracting additional information from EMBs. New concepts have emerged exploring the multifaceted significance of myocardial injury, minimal rejection patterns supported by molecular profiles, and lesions of arteriolitis/vasculitis in the setting of T cell-mediated rejection (TCMR) and antibody-mediated rejection (AMR). The orphaned lesion known as Quilty effect or nodular endocardial infiltrates. A state-of-the-art session with historical aspects and current dilemmas was reviewed, and possible pathogenesis proposed, based on advances in immunology to explain conflicting data. The Quilty effect will be the subject of a multicenter project to explore whether it functions as a tertiary lymphoid organ.

Racial and ethnic disparities in outcomes after heart transplantation: A systematic review of contributing factors and future directions to close the outcomes gap

The demographics of patients undergoing heart transplantation in the United States have shifted over the last 10 years, with an increasing number of racial and ethnic minorities undergoing heart transplant. Multiple studies have shown that survival of African American patients after heart transplantation is lower compared with other ethnic groups. We review the data supporting the presence of this outcome disparity and examine the multiple mechanisms that contribute. With an increasingly diverse population in the United States, knowledge of these disparities, their mechanisms, and ways to improve outcomes is essential.

Immunosuppression following heart transplantation: prospects and challenges

Immunosuppression after heart transplantation has significantly reduced the incidence of cellular rejection and improved patient outcomes with the routine use of calcineurin inhibitors. Antimetabolites and proliferation signal inhibitors add to the improvement in patient outcomes, particularly with respect to the reduced burden of cardiac allograft vasculopathy. Patients with antibody sensitization are potentially at higher risk of postoperative complications. Sensitized patients are undergoing heart transplantation with increased frequency, in part due to the emergence of ventricular assist device use as a bridge to heart transplantation. Despite improvements in immunosuppressive therapies, many challenges face physicians and patients, which will further refine and improve care of the post-heart transplant patient.