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Ettenger RB, Seifert ME, Blydt-Hansen T, Briscoe DM, Holman J, Weng PL, Srivastava R, Fleming J, Malekzadeh M, Pearl M. Detection of Subclinical Rejection in Pediatric Kidney Transplantation: Current and Future Practices. Pediatr Transplant 2024; 28:e14836. [PMID: 39147695 DOI: 10.1111/petr.14836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 07/19/2024] [Accepted: 07/22/2024] [Indexed: 08/17/2024]
Abstract
INTRODUCTION The successes in the field of pediatric kidney transplantation over the past 60 years have been extraordinary. Year over year, there have been significant improvements in short-term graft survival. However, improvements in longer-term outcomes have been much less apparent. One important contributor has been the phenomenon of low-level rejection in the absence of clinical manifestations-so-called subclinical rejection (SCR). METHODS Traditionally, rejection has been diagnosed by changes in clinical parameters, including but not limited to serum creatinine and proteinuria. This review examines the shortcomings of this approach, the effects of SCR on kidney allograft outcome, the benefits and drawbacks of surveillance biopsies to identify SCR, and new urine and blood biomarkers that define the presence or absence of SCR. RESULTS Serum creatinine is an unreliable index of SCR. Surveillance biopsies are the method most utilized to detect SCR. However, these have significant drawbacks. New biomarkers show promise. These biomarkers include blood gene expression profiles and donor derived-cell free DNA; urine gene expression profiles; urinary cytokines, chemokines, and metabolomics; and other promising blood and urine tests. CONCLUSION Specific emphasis is placed on studies carried out in pediatric kidney transplant recipients. TRIAL REGISTRATION ClinicalTrials.gov: NCT03719339.
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Affiliation(s)
- Robert B Ettenger
- Division of Nephrology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Michael E Seifert
- Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Tom Blydt-Hansen
- Multi-Organ Transplant Program, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - David M Briscoe
- Division of Nephrology, Department of Pediatrics Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - John Holman
- Transplant Genomics Inc., Framingham, Massachusetts, USA
| | - Patricia L Weng
- Division of Nephrology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Rachana Srivastava
- Division of Nephrology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - James Fleming
- Transplant Genomics Inc., Framingham, Massachusetts, USA
| | - Mohammed Malekzadeh
- Division of Nephrology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Meghan Pearl
- Division of Nephrology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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Graver AS, Lee D, Power DA, Whitlam JB. Understanding Donor-derived Cell-free DNA in Kidney Transplantation: An Overview and Case-based Guide for Clinicians. Transplantation 2023; 107:1675-1686. [PMID: 36579675 DOI: 10.1097/tp.0000000000004482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Kidney transplant recipients undergo lifelong monitoring of allograft function and evaluation for transplant complications. The current monitoring paradigm utilizes blood, urine, and tissue markers that are insensitive, nonspecific, or invasive to obtain. As a result, problems are detected late, after significant damage has accrued, and often beyond the time at which complete resolution is possible. Indeed, most kidney transplants eventually fail, usually because of chronic rejection and other undetected injury. There is a clear need for a transplant-specific biomarker that enables a proactive approach to monitoring via early detection of reversible pathology. A biomarker that supports timely and personalized treatment would assist in achieving the ultimate goal of improving allograft survival and limiting therapeutic toxicity to the recipient. Donor-derived cell-free DNA (ddcfDNA) has been proposed as one such transplant biomarker. Although the test is presently utilized most in the United States, it is conceivable that its use will become more widespread. This review covers aspects of ddcfDNA that support informed use of the test by general nephrologists, including the basic biology of ddcfDNA, methodological nuances of testing, and general recommendations for use in the kidney transplant population. Clinical contexts are used to illustrate evidence-supported interpretation of ddcfDNA results and subsequent management. Finally, knowledge gaps and areas for further study are discussed.
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Affiliation(s)
- Alison S Graver
- Kidney Transplant Service, Department of Nephrology, Austin Health, Heidelberg, VIC, Australia
- Department of Medicine, University of Melbourne, Parkville, VIC, Australia
| | - Darren Lee
- Kidney Transplant Service, Department of Nephrology, Austin Health, Heidelberg, VIC, Australia
- Department of Renal Medicine, Eastern Health Clinical School, Monash University, Box Hill, VIC, Australia
| | - David A Power
- Kidney Transplant Service, Department of Nephrology, Austin Health, Heidelberg, VIC, Australia
- Department of Medicine, University of Melbourne, Parkville, VIC, Australia
| | - John B Whitlam
- Kidney Transplant Service, Department of Nephrology, Austin Health, Heidelberg, VIC, Australia
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, VIC, Australia
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Molecular Markers of Kidney Transplantation Outcome: Current Omics Tools and Future Developments. Int J Mol Sci 2022; 23:ijms23116318. [PMID: 35682996 PMCID: PMC9181061 DOI: 10.3390/ijms23116318] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 02/04/2023] Open
Abstract
Purpose of review: The emerging field of molecular predictive medicine is aiming to change the traditional medical approach in renal transplantation. Many studies have explored potential biomarker molecules with predictive properties in renal transplantation, issued from omics research. Herein, we review the biomarker molecules of four technologies (i.e., Genomics, Transcriptomics, Proteomics, and Metabolomics) associated with favorable kidney transplant outcomes. Recent findings: Several panels of molecules have been associated with the outcome that the majority of markers are related to inflammation and immune response; although. other molecular ontologies are also represented, such as proteasome, growth, regeneration, and drug metabolism. Throughout this review, we highlight the lack of properly validated statistical demonstration. Indeed, the most preeminent molecular panels either remain at the limited size study stage or are not confirmed during large-scale studies. At the core of this problem, we identify the methodological shortcomings and propose a comprehensive workflow for discovery and validation of molecular biomarkers that aims to improve the relevance of these tools in the future. Summary: Overall, adopting a patient management through omics approach could bring remarkable improvement to transplantation success. An increased effort and investment between scientists, medical biologists, and clinicians seem to be the path toward a proper solution.
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New Insights from Metabolomics in Pediatric Renal Diseases. CHILDREN 2022; 9:children9010118. [PMID: 35053744 PMCID: PMC8774568 DOI: 10.3390/children9010118] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/09/2022] [Accepted: 01/13/2022] [Indexed: 12/11/2022]
Abstract
Renal diseases in childhood form a spectrum of different conditions with potential long-term consequences. Given that, a great effort has been made by researchers to identify candidate biomarkers that are able to influence diagnosis and prognosis, in particular by using omics techniques (e.g., metabolomics, lipidomics, genomics, and transcriptomics). Over the past decades, metabolomics has added a promising number of ‘new’ biomarkers to the ‘old’ group through better physiopathological knowledge, paving the way for insightful perspectives on the management of different renal diseases. We aimed to summarize the most recent omics evidence in the main renal pediatric diseases (including acute renal injury, kidney transplantation, chronic kidney disease, renal dysplasia, vesicoureteral reflux, and lithiasis) in this narrative review.
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Deville KA, Seifert ME. Biomarkers of alloimmune events in pediatric kidney transplantation. Front Pediatr 2022; 10:1087841. [PMID: 36741087 PMCID: PMC9895094 DOI: 10.3389/fped.2022.1087841] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/28/2022] [Indexed: 01/21/2023] Open
Abstract
Alloimmune events such as the development of de novo donor-specific antibody (dnDSA), T cell-mediated rejection (TCMR), and antibody-mediated rejection (ABMR) are the primary contributors to kidney transplant failure in children. For decades, a creatinine-based estimated glomerular filtration rate (eGFR) has been the non-invasive gold standard biomarker for detecting clinically significant alloimmune events, but it suffers from low sensitivity and specificity, especially in smaller children and older allografts. Many clinically "stable" children (based on creatinine) will have alloimmune events known as "subclinical acute rejection" (based on biopsy) that merely reflect the inadequacy of creatinine-based estimates for alloimmune injury rather than a distinct phenotype from clinical rejection with allograft dysfunction. The poor biomarker performance of creatinine leads to many unnecessary surveillance and for-cause biopsies that could be avoided by integrating non-invasive biomarkers with superior sensitivity and specificity into current clinical paradigms. In this review article, we will present and appraise the current state-of-the-art in monitoring for alloimmune events in pediatric kidney transplantation. We will first discuss the current clinical standards for assessing the presence of alloimmune injury and predicting long-term outcomes. We will review principles of biomarker medicine and the application of comprehensive metrics to assess the performance of a given biomarker against the current gold standard. We will then highlight novel blood- and urine-based biomarkers (with special emphasis on pediatric biomarker studies) that have shown superior diagnostic and prognostic performance to the current clinical standards including creatinine-based eGFR. Finally, we will review some of the barriers to translating this research and implementing emerging biomarkers into common clinical practice, and present a transformative approach to using multiple biomarker platforms at different times to optimize the detection and management of critical alloimmune events in pediatric kidney transplant recipients.
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Affiliation(s)
- Kyle A Deville
- Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama Heersink School of Medicine, Birmingham, AL, United States
| | - Michael E Seifert
- Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama Heersink School of Medicine, Birmingham, AL, United States
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Ehlayel A, Simms KJA, Ashoor IF. Emerging monitoring technologies in kidney transplantation. Pediatr Nephrol 2021; 36:3077-3087. [PMID: 33523298 DOI: 10.1007/s00467-021-04929-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/22/2020] [Accepted: 01/06/2021] [Indexed: 11/27/2022]
Abstract
Non-invasive technologies to monitor kidney allograft health utilizing high-throughput assays of blood and urine specimens are emerging out of the research realm and slowly becoming part of everyday clinical practice. HLA epitope analysis and eplet mismatch score determination promise a more refined approach to the pre-transplant recipient-donor HLA matching that may lead to reduced rejection risk. High-resolution HLA typing and multiplex single antigen bead assays are identifying potential new offending HLA antibody subtypes. There is increasing recognition of the deleterious role non-HLA antibodies play in post-transplant outcomes. Donor-derived cell-free DNA detected by next-generation sequencing is a promising biomarker for kidney transplant rejection. Multi-omics techniques are shedding light on discrete genomic, transcriptomic, proteomic, and metabolomic signatures that correlate with and predict allograft outcomes. Over the next decade, a comprehensive approach to optimize kidney matching and monitor transplant recipients for acute and chronic graft dysfunction will likely involve a combination of those emerging technologies summarized in this review.
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Affiliation(s)
- Abdulla Ehlayel
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA
| | - K'joy J A Simms
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA
| | - Isa F Ashoor
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA.
- Department of Pediatrics, LSU Health New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA.
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Challenges of Diagnosing Antibody-Mediated Rejection: The Role of Invasive and Non-Invasive Biomarkers. ACTA ACUST UNITED AC 2021; 57:medicina57050439. [PMID: 34063583 PMCID: PMC8147623 DOI: 10.3390/medicina57050439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/22/2022]
Abstract
Kidney transplantation is the best treatment modality for end-stage kidney disease, leading to improvement in a patient’s quality and quantity of life. With significant improvements in short-term outcomes, prolonging long-term allograft and patient survival remain ongoing challenges. The ability to monitor allograft function, immune tolerance and predict rejection accurately would enable personalization and better prognostication during post-transplant care. Though kidney biopsy remains the backbone of transplant diagnostics, emerging biomarkers can help detecting kidney allograft injury early enough to prevent permanent damage and detect injury before it is clinically apparent. In this review, we summarize the recent biomarkers that have shown promise in the prediction of acute rejection with a focus on antibody-mediated rejection in kidney transplantation.
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Kim MY, Brennan DC. Therapies for Chronic Allograft Rejection. Front Pharmacol 2021; 12:651222. [PMID: 33935762 PMCID: PMC8082459 DOI: 10.3389/fphar.2021.651222] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/10/2021] [Indexed: 12/14/2022] Open
Abstract
Remarkable advances have been made in the pathophysiology, diagnosis, and treatment of antibody-mediated rejection (ABMR) over the past decades, leading to improved graft outcomes. However, long-term failure is still high and effective treatment for chronic ABMR, an important cause of graft failure, has not yet been identified. Chronic ABMR has a relatively different phenotype from active ABMR and is a slowly progressive disease in which graft injury is mainly caused by de novo donor specific antibodies (DSA). Since most trials of current immunosuppressive therapies for rejection have focused on active ABMR, treatment strategies based on those data might be less effective in chronic ABMR. A better understanding of chronic ABMR may serve as a bridge in establishing treatment strategies to improve graft outcomes. In this in-depth review, we focus on the pathophysiology and characteristics of chronic ABMR along with the newly revised Banff criteria in 2017. In addition, in terms of chronic ABMR, we identify the reasons for the resistance of current immunosuppressive therapies and look at ongoing research that could play a role in setting better treatment strategies in the future. Finally, we review non-invasive biomarkers as tools to monitor for rejection.
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Affiliation(s)
| | - Daniel C. Brennan
- Department of Internal Medicine, Johns Hopkins School of Medicine, Baltimore, MD, United States
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Abstract
Single-cell RNA sequencing (scRNA-seq) allows the measurement of transcriptomes from individual cells providing new insights into complex biological systems. scRNA-seq has enabled the identification of rare cell types, new cell states, and intercellular communication networks that may be masked by traditional bulk transcriptional profiling. Researchers are increasingly using scRNA-seq to comprehensively characterize complex organs in health and disease. The diversity of immune cell types, some present at low frequency, in a transplanted organ undergoing rejection makes scRNA-seq ideally suited to characterize transplant pathologies because it can quantify subtle transcriptional differences between rare cell types. In this review, we discuss single-cell sequencing methods and their application in transplantation to date, current challenges, and future directions. We believe that the remarkably rapid pace of technological development in this field makes it likely that single-cell technologies such as scRNA-seq will have an impact on clinical transplantation within a decade.
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