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Cohen GS, Gareau AJ, Kallarakal MA, Farooq T, Bettinotti MP, Sullivan HC, Madbouly A, Krummey SM. HLA Genotype Imputation Results in Largely Accurate Epitope Mismatch Risk Categorization Across Racial Groups. Transplant Direct 2024; 10:e1639. [PMID: 38911277 PMCID: PMC11191912 DOI: 10.1097/txd.0000000000001639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/09/2024] [Indexed: 06/25/2024] Open
Abstract
Background Biomarkers that predict posttransplant alloimmunity could lead to improved long-term graft survival. Evaluation of the number of mismatched epitopes between donor and recipient HLA proteins, termed molecular mismatch analysis, has emerged as an approach to classify transplant recipients as having high, intermediate, or low risk of graft rejection. When high-resolution genotypes are unavailable, molecular mismatch analysis requires algorithmic assignment, or imputation, of a high-resolution genotyping. Although imputation introduces inaccuracies in molecular mismatch analyses, it is unclear whether these inaccuracies would impact the clinical risk assessment for graft rejection. Methods Using renal transplant patients and donors from our center, we constructed cohorts of surrogate donor-recipient pairs with high-resolution and low-resolution HLA genotyping that were racially concordant or discordant. We systemically assessed the impact of imputation on molecular mismatch analysis for cohorts of 180-200 donor-recipient pairs for each of 4 major racial groups. We also evaluated the effect of imputation for a racially diverse validation cohort of 35 real-world renal transplant pairs. Results In the surrogate donor-recipient cohorts, imputation preserved the molecular mismatch risk category for 90.5%-99.6% of racially concordant donor-recipient pairs and 92.5%-100% of racially discordant pairs. In the validation cohort, which comprised 72% racially discordant pairs, we found that imputation preserved the molecular mismatch risk category for 97.1% of pairs. Conclusions Overall, these data demonstrate that imputation preserves the molecular mismatch risk assessment in the vast majority of cases and provides evidence supporting imputation in the performance of molecular mismatch analysis for clinical assessment.
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Affiliation(s)
- Gregory S. Cohen
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Alison J. Gareau
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
- Johns Hopkins Immunogenetics Laboratory, Baltimore, MD
| | | | - Tayyiaba Farooq
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Maria P. Bettinotti
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
- Johns Hopkins Immunogenetics Laboratory, Baltimore, MD
| | - H. Cliff Sullivan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Abeer Madbouly
- National Marrow Donor Program/Be The Match, Minneapolis, MN
- Center for International Blood and Marrow Transplant Research, Minneapolis, MN
| | - Scott M. Krummey
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
- Johns Hopkins Immunogenetics Laboratory, Baltimore, MD
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Combined Analysis of HLA Class II Eplet Mismatch and Tacrolimus Levels for the Prediction of De Novo Donor Specific Antibody Development in Kidney Transplant Recipients. Int J Mol Sci 2022; 23:ijms23137357. [PMID: 35806362 PMCID: PMC9267119 DOI: 10.3390/ijms23137357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 02/05/2023] Open
Abstract
We investigated whether HLA class II eplet mismatch was related to dnDSA development and analyzed its combined impact with tacrolimus levels for kidney transplantation outcomes. A total of 347 kidney transplants were included. HLA Matchmaker was used for the single molecular eplet, total eplet, antibody (Ab)-verified eplet mismatch analyses, and Ab-verified single molecular analysis to identify HLA-DR/DQ molecular thresholds for the risk of dnDSA development. A time-weighted tacrolimus trough level (TAC-C0) of 5 ng/mL and a TAC-C0 time-weighted coefficient variability (TWCV) of 20% were applied to find the combined effects on dnDSA development. A high level of mismatch for single molecular eplet (DQ ≥ 10), total eplet (DQ ≥ 12), Ab-verified eplet (DQ ≥ 4), and Ab-verified single molecular eplet (DQ ≥ 4) significantly correlated with HLA class II dnDSA development. Class II dnDSA developed mostly in patients with low TAC-C0 and high eplet mismatch. In the multivariable analyses, low TAC-C0 and high eplet mismatch showed the highest hazard ratio for the development of dnDSA. No significant combined effect was observed in dnDSA development according to TWCV. In conclusion, the determination of HLA class II eplet mismatch may improve the risk stratification for dnDSA development, especially in conjunction with tacrolimus trough levels.
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3
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Lobashevsky A, Niemann M, Kowinski B, Higgins N, Abdel-Wareth L, Atrabulsi B, Roe D, Hage C. Formation of donor-specific antibodies depends on the epitope load of mismatched hlas in lung transplant recipients: A retrospective single-center study. Clin Transplant 2022; 36:e14755. [PMID: 35771140 DOI: 10.1111/ctr.14755] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/18/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
The development of donor-specific antibodies (DSA) has a significant impact on graft outcome in solid organ transplantation. Mismatched HLAs are recognized directly and indirectly by the recipient immune system. Both pathways occur in parallel and result in the generation of plasma cells, DSA, cytotoxic and T helper lymphocytes. Here, we present the results of an analysis of the epitope load of mismatched HLAs in a cohort of 220 lung transplant recipients using two in silico algorithms, HLAMatchmaker and PIRCHE-II (Predicted Indirectly ReCognizable HLA Epitopes). De novo DSA (dnDSA) were detected by single antigen bead assays. The percentage of recipients who developed dnDSA was significantly higher in the group of patients who received lung transplants with a mismatching score above the detected threshold than in the group of patients who received lung transplants with a mismatching score below the threshold. In a multivariate Cox proportional hazard analysis, the PIRCHE-II score appeared to be a superior predictor of dnDSA formation. In addition, PIRCHE-II technology was shown to be useful in predicting separate dnDSA1 and dnDSA2 formation. We conclude that both algorithms can be used for the evaluation of the epitope load of mismatched HLAs and the prediction of DSA development in lung transplant recipients. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Andrew Lobashevsky
- Transplant Immunology Laboratory, Methodist Hospital, IUHealth Inc., Indianapolis, IN, USA.,Mubadala, National Reference Laboratory, HLA Laboratory, Abu Dhabi, UAE
| | | | - Brenda Kowinski
- Lung Transplant Program, IUHealth Inc., Indiana University School of Medicine, Indianapolis, IN, USA
| | - Nancy Higgins
- Transplant Immunology Laboratory, Methodist Hospital, IUHealth Inc., Indianapolis, IN, USA
| | | | - Basel Atrabulsi
- Mubadala, National Reference Laboratory, HLA Laboratory, Abu Dhabi, UAE
| | - David Roe
- Lung Transplant Program, IUHealth Inc., Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chadi Hage
- McGowen Institute of Regenerative medicine, UPMC, University of Pittsburgh, Pittsburgh, PA, USA
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4
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Duquesnoy RJ. Autobiographical perspectives on HLA epitopes: Past, present and future. Hum Immunol 2022; 83:199-203. [DOI: 10.1016/j.humimm.2022.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/10/2021] [Accepted: 01/05/2022] [Indexed: 11/28/2022]
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5
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Rosser C, Sage D. Approaches for the characterization of clinically relevant pre-transplant human leucocyte antigen (HLA) antibodies in solid organ transplant patients. Int J Immunogenet 2021; 48:385-402. [PMID: 34346180 DOI: 10.1111/iji.12552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/30/2021] [Accepted: 07/22/2021] [Indexed: 11/27/2022]
Abstract
The avoidance of antibody-mediated rejection (AMR) attributed to human leucocyte antigen (HLA) antibody incompatibility remains an essential function of clinical Histocompatibility and Immunogenetics (H&I) laboratories who are supporting solid organ transplantation. Developments in HLA antibody identification assays over the past thirty years have greatly reduced unexpected positive cellular crossmatches and improved solid organ transplant outcomes. For sensitized patients, the decision to register unacceptable HLA antigen mismatches is often heavily influenced by results from solid phase antibody assays, particularly the Luminex® Single Antigen Bead (SAB) assays, although the clinical relevance of antibodies identified solely by these assays remains unclear. As such, the identification of non-clinically relevant antibodies may proportionally increase the number of unacceptable transplant mismatches registered, with an associated increase in waiting time for a compatible organ. We reflect on the clinical relevance of antibodies identified solely by the Luminex SAB® assays and consider whether the application of additional assays and/or tools could further develop our ability to define the clinical relevance of antibodies identified in patient sera. Improvements in this area would assist equity of access to a compatible transplant for highly sensitized patients awaiting a solid organ transplant.
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Affiliation(s)
- Carla Rosser
- NHS Blood and Transplant (Tooting), Histocompatibility and Immunogenetics, London, UK
| | - Deborah Sage
- NHS Blood and Transplant (Tooting), Histocompatibility and Immunogenetics, London, UK
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6
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On Path to Informing Hierarchy of Eplet Mismatches as Determinants of Kidney Transplant Loss. Kidney Int Rep 2021; 6:1567-1579. [PMID: 34169197 PMCID: PMC8207474 DOI: 10.1016/j.ekir.2021.03.877] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 03/08/2021] [Indexed: 11/22/2022] Open
Abstract
Introduction To mitigate risks related to human leukocyte antigen (HLA) incompatibility, we assessed whether certain structurally defined HLA targets present in donors but absent from recipients, known as eplet mismatches (EMM), are associated with death-censored graft failure (DCGF). Methods We studied a cohort of 118,313 American 0% panel reactive antibodies (PRA) first kidney transplant recipients (2000 to 2015) from the Scientific Registry of Transplant Recipients. Imputed allele-level donor and recipient HLA-A, -B, -C, -DRB1, and -DQB1 genotypes were converted to the repertoire of EMM. We fit survival models for each EMM with significance thresholds corrected for false discovery rate and validated those in an independent PRA > 0% cohort. We conducted network-based analyses to model relationships among EMM and developed models to select the subset of EMM most predictive of DCGF. Results Of 412 EMM observed, 119 class I and 118 class II EMM were associated with DCGF. Network analysis showed that although 210 eplets formed profiles of 2 to 12 simultaneously occurring EMMs, 202 were singleton EMMs that were not involved in any profile. A variable selection procedure identified 55 single HLA class I and II EMMs in 70% of the dataset; of those, 15 EMMs (9 singleton and 6 involved in profiles) were predictive of DCGF in the remaining dataset. Conclusion Our analysis distinguished increasingly smaller subsets of EMMs associated with increased risk of DCGF. Validation of these EMMs as important predictors of transplant outcomes (in contrast to acceptable EMMs) in datasets with measured allele-level genotypes will support their role as immunodominant EMMs worthy of consideration in organ allocation schemes.
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7
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Swann JB, Holland SJ, Petersen M, Pietsch TW, Boehm T. The immunogenetics of sexual parasitism. Science 2020; 369:1608-1615. [PMID: 32732279 DOI: 10.1126/science.aaz9445] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 07/17/2020] [Indexed: 01/29/2023]
Abstract
Sexual parasitism has evolved as a distinctive mode of reproduction among deep-sea anglerfishes. The permanent attachment of males to host females observed in these species represents a form of anatomical joining, which is otherwise unknown in nature. Pronounced modifications to immune facilities are associated with this reproductive trait. The genomes of species with temporarily attaching males lack functional aicda genes that underpin affinity maturation of antibodies. Permanent attachment is associated with additional alterations, culminating in the loss of functional rag genes in some species, abolishing somatic diversification of antigen receptor genes, the hallmark of canonical adaptive immunity. In anglerfishes, coevolution of innate and adaptive immunity has been disentangled, implying that an alternative form of immunity supported the emergence of this evolutionarily successful group of vertebrates.
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Affiliation(s)
- Jeremy B Swann
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, D-79108 Freiburg, Germany.
| | - Stephen J Holland
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Malte Petersen
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Theodore W Pietsch
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105-5020, USA
| | - Thomas Boehm
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, D-79108 Freiburg, Germany.
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8
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Sharma A, Taverniti A, Graf N, Teixeira-Pinto A, Lewis JR, Lim WH, Alexander SI, Durkan A, Craig JC, Wong G. The association between human leukocyte antigen eplet mismatches, de novo donor-specific antibodies, and the risk of acute rejection in pediatric kidney transplant recipients. Pediatr Nephrol 2020; 35:1061-1068. [PMID: 32065279 DOI: 10.1007/s00467-020-04474-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 12/16/2019] [Accepted: 01/03/2020] [Indexed: 10/25/2022]
Abstract
BACKGROUND The longitudinal relationship between HLA class I and II eplet mismatches, de novo donor-specific antibodies (dnDSA) development, and acute rejection after transplantation in childhood is unknown. METHODS Eplet mismatches at HLA class I and II loci were calculated retrospectively for each donor/recipient pair transplanted between 2005 and 2015 at a single Australian center. Logistic regression analyses were conducted to determine the association between the number of eplet mismatches, dnDSA, and acute rejection. RESULTS The cohort comprised 59 children (aged 0-18 years) who received their first kidney allograft and were followed for median (interquartile range) 4.5 (± 2.6) years. Overall, 32% (19/59) developed dnDSA (class I 3% (2/59), class II 14% (8/59), 15% class I and II (9/59)), and 24% (14/59) developed biopsy-proven acute rejection. Every unit increase in class I and II eplet mismatches corresponded to an increase in risk of class I (odds ratio (OR) 1.22, 95% CI 1.07-1.39, p < 0.01) and class II (OR 1.06, 95% CI 1.01-1.11, p = 0.02) dnDSA development. Compared with recipients without dnDSA, class I and II dnDSA were associated with direction of effect towards increased risk of acute cellular rejection (class I: OR 5.87, 95% CI 0.99-34.94, p = 0.05; class II: OR 12.00, 95% CI 1.25-115.36, p = 0.03) and acute antibody-mediated rejection (class I: OR 25.67, 95% CI 3.54-186.10, p < 0.01; class II: OR 9.71, 95% CI 1.64-57.72, p = 0.01). CONCLUSIONS Increasing numbers of HLA class I or II eplet mismatches were associated with the development of dnDSA. Children who developed dnDSA were also more likely to develop acute rejection compared with children without dnDSA.
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Affiliation(s)
- Ankit Sharma
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia. .,School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia.
| | - Anne Taverniti
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia
| | - Nicole Graf
- Department of Histopathology, Children's Hospital at Westmead, Sydney, Australia
| | - Armando Teixeira-Pinto
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia.,School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Joshua R Lewis
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia.,School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | - Wai H Lim
- School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.,Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Australia
| | - Stephen I Alexander
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia
| | - Anne Durkan
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia
| | - Jonathan C Craig
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia.,School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia.,College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Germaine Wong
- Centre for Kidney Research, Children's Hospital at Westmead, Sydney, Australia.,School of Public Health, Sydney Medical School, The University of Sydney, Sydney, Australia
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9
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Matern BM, Olieslagers TI, Groeneweg M, Duygu B, Wieten L, Tilanus MGJ, Voorter CEM. Long-Read Nanopore Sequencing Validated for Human Leukocyte Antigen Class I Typing in Routine Diagnostics. J Mol Diagn 2020; 22:912-919. [PMID: 32302780 DOI: 10.1016/j.jmoldx.2020.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/03/2020] [Accepted: 04/02/2020] [Indexed: 01/23/2023] Open
Abstract
Matching of human leukocyte antigen (HLA) gene polymorphisms by high-resolution DNA sequence analysis is the gold standard for determining compatibility between patient and donor for hematopoietic stem cell transplantation. Single-molecule sequencing (PacBio or MinION) is a newest (third) generation sequencing approach. MinION is a nanopore sequencing platform, which provides long targeted DNA sequences. The long reads provide unambiguous phasing, but the initial high error profile prevented its use in high-impact applications, such as HLA typing for HLA matching of donor and recipient in the transplantation setting. Ongoing developments on instrumentation and basecalling software have improved the per-base accuracy of 1D2 nanopore reads tremendously. In the current study, two validation panels of samples covering 70 of the 71 known HLA class I allele groups were used to compare third field sequences obtained by MinION, with Sanger sequence-based typing showing a 100% concordance between both data sets. In addition, the first validation panel was used to set the acceptance criteria for the use of MinION in a routine setting. The acceptance criteria were subsequently confirmed with the second validation panel. In summary, the present study describes validation and implementation of nanopore sequencing HLA class I typing method and illustrates that nanopore sequencing technology has advanced to a point where it can be used in routine diagnostics with high accuracy.
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Affiliation(s)
- Benedict M Matern
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Timo I Olieslagers
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Mathijs Groeneweg
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Burcu Duygu
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Lotte Wieten
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Marcel G J Tilanus
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Christina E M Voorter
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands.
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10
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Epitope matching in kidney transplantation: recent advances and current limitations. Curr Opin Organ Transplant 2020; 24:370-377. [PMID: 31135563 DOI: 10.1097/mot.0000000000000657] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Evolution of human leukocyte antigen (HLA) molecular typing techniques has progressively enabled more accurate determination of the three-dimensional building blocks that form the antibody accessibility and binding sites of each HLA allele. These immunogenic HLA regions known as epitopes are composed of polymorphic sequences of amino acid residues termed eplets. This review provides a critical appraisal of the current understanding of epitope compatibility in kidney transplantation. RECENT FINDINGS There is a tendency to suggest that epitope matching is likely to be superior to broad antigen HLA matching such that the allocation of donor kidneys to patients with a more favorable epitope compatibility profile may lead to better allograft outcomes. A growing body of work has highlighted the association between a greater number of eplet mismatches and adverse allograft outcomes, and approaches using eplet matching have been successfully implemented in organ allocation programs. However, our understanding of epitope compatibility remains in its infancy, requiring further and more in-depth evaluation. Critically, it remains unclear how best to translate findings derived at the population level to the care of individual patients. Questions that need to be answered include a lack of consensus in the definition and interpretation of epitope compatibility, are class I and II compatibility of similar clinical importance, how best to define predetermined mismatch thresholds for utilization in organ allocation, and whether other properties such as differences in electrostatic potential between donor and recipient HLA alleles are also important in determining immunological compatibility. SUMMARY Epitope matching likely represents a valid progression in understanding donor-recipient HLA compatibility. However, more clinical data and a better understanding about differences in methods to determine epitope compatibility are required before the approach can be widely applied in clinical practice.
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11
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Epitope-based human leukocyte antigen matching for transplantation: a personal perspective of its future. Curr Opin Organ Transplant 2019; 23:486-492. [PMID: 29995674 DOI: 10.1097/mot.0000000000000539] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE OF REVIEW This study reflects my personal experience with the characterization of human leukocyte antigen (HLA) epitopes and their significance in HLA matching for transplantation. It offers a subjective assessment what further studies are needed to have this concept be applied in the clinical setting. RECENT FINDINGS This study addresses the structural characteristics of antibody-reactive HLA epitopes determined by different methods, eplet-associated antibody analysis and acceptable mismatching for sensitized patients and eplet immunogenicity and determination of mismatch permissibility. BASIC IMPLICATIONS: for clinical practice and research consider the need for further studies of the structural basis of antibody-verified HLA epitopes determined in different techniques and their clinical relevance, the biological basis of epitope immunogenicity and determinations of permissible mismatches and a computerized clinical transplant database with an Artificial Intelligence component that can generate evidence-based information for the practical application of epitope-based HLA matching.
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12
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Delion A, Girerd S, Duarte K, Girerd N, Schikowski J, Kessler M, Frimat L, Aarnink A. Which is the best predictor of de novo donor-specific antibodies in a cohort of non-sensitized first kidney transplantation: Antigenic, allelic, epitope, or physiochemical HLA mismatches? Clin Transplant 2019; 33:e13508. [PMID: 30821002 DOI: 10.1111/ctr.13508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 01/11/2019] [Accepted: 01/28/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND Assessment of human leukocyte antigen (HLA) matching by using high-resolution allele typing and knowledge of HLA molecule structure may lead to better prediction of de novo donor-specific antibody (dnDSA) development. METHODS We conducted a single-center cohort study among 150 non-sensitized first kidney transplant recipients to compare the association between antigenic (Ag), allelic (Al), eplet (Ep), amino acid (AAMS) HLA matching and electrostatic (EMS) and hydrophobic (HMS) mismatch scores, and the development of dnDSA. RESULTS After a mean follow-up time of 49.3 ± 17.7 months, 18 patients (12%) developed dnDSA. The number of HLA mismatches (MM) was significantly associated with the development of dnDSA. The optimal threshold, determined by Harrell's C-index, varied according to the method (5 MM for Ag, P = 0.006; 6 for Al, P = 0.009; 22 for Ep, P = 0.005; 42 for AAMS, P = 0.0007; 45 for EMS, P = 0.009 and 44 for HMS, P = 0.026). C-indices were similar for all matching approaches, suggesting a similar prediction of dnDSA development. CONCLUSION In this cohort of low immunological risk transplant patients, the use of Al or Ep matching did not improve the prediction of dnDSA development in comparison with the traditional approach.
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Affiliation(s)
- Alexandra Delion
- Service de Néphrologie et Transplantation rénale, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France
| | - Sophie Girerd
- Service de Néphrologie et Transplantation rénale, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France.,INSERM, Centre d'Investigations Cliniques Plurithématique 1433, Université de Lorraine, CHRU de Nancy and F-CRIN INI-CRCT, Nancy, France
| | - Kevin Duarte
- INSERM, Centre d'Investigations Cliniques Plurithématique 1433, Université de Lorraine, CHRU de Nancy and F-CRIN INI-CRCT, Nancy, France
| | - Nicolas Girerd
- INSERM, Centre d'Investigations Cliniques Plurithématique 1433, Université de Lorraine, CHRU de Nancy and F-CRIN INI-CRCT, Nancy, France
| | - Johan Schikowski
- Service de Néphrologie et Transplantation rénale, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France
| | - Michèle Kessler
- Service de Néphrologie et Transplantation rénale, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France
| | - Luc Frimat
- Service de Néphrologie et Transplantation rénale, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France
| | - Alice Aarnink
- Laboratoire d'Histocompatibilité, CHRU Nancy Brabois, Vandœuvre-lès-Nancy, France
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13
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Kasimatis E, Fylaktou A, Karampatakis T, Schoina M, Zarras C, Anastasiou A, Papachristou M, Boukla A, Daoudaki M, Fouzas I, Papagianni A. Human Leukocyte Antigen Compatibility and De Novo Donor-Specific Antibodies in Long-term Renal Transplant Patients With Stable Graft Function. Transplant Proc 2019; 51:413-415. [PMID: 30879554 DOI: 10.1016/j.transproceed.2019.01.013] [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: 11/20/2022]
Abstract
PURPOSE De novo donor-specific antibodies (DSA) are associated with antibody-mediated rejection leading to late renal transplant failure. The aim of this study was to evaluate whether HLA compatibility is associated with sensitization along with other risk factors. METHODS Eighty-nine stable renal transplant recipients (47 men) were studied. Patients were classified into 2 groups according to HLA compatibility between donor and recipient, group A (1-4/8 matches) and group B (5-8/8 matches). Cold ischemia time (CIT) and delayed graft function (DGF) were recorded along with time with a functional graft. Anti-HLA antibodies were detected using a Luminex single-antigen bead assay and were further classified into DSA and non-DSA. RESULTS HLA group A consisted of 49 (56%) transplant recipients while 38 (44%) were classified to group B, with functional grafts for 10.9 ± 6.7 and 14.8 ± 8.5 years, respectively (P = .019). Group A patients had more anti-HLA antibodies than group Β (P = .001) and this correlation was retained for DSA patients. De novo anti-HLA were detected in 40 patients; DSA were detected in 19 (21.8%). DSA (+) patients had recorded with functional renal grafts for 11 ± 5 years, compared to 14.4 ± 8.6 years (P = .048) for anti-HLA negative patients. Increased CIT and DGF were associated with anti-HLA antibodies detection but no with DSA. CONCLUSION HLA compatibility is probably correlated with DSA in a context of a more general anti-HLA sensitization, and both have a negative effect on long-term renal graft outcome.
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Affiliation(s)
- E Kasimatis
- Department of Nephrology, Aristotle University Medical School, Hippokration General Hospital, Thessaloniki, Greece.
| | - A Fylaktou
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - T Karampatakis
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - M Schoina
- Department of Nephrology, Aristotle University Medical School, Hippokration General Hospital, Thessaloniki, Greece
| | - C Zarras
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - A Anastasiou
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - M Papachristou
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - A Boukla
- National Peripheral Histocompatibility Center, Immunology Department, Hippokration General Hospital, Thessaloniki, Greece
| | - M Daoudaki
- Division of Organ Transplantation, Department of Surgery, Aristotle University Medical School, Hippokration General Hospital, Thessaloniki, Greece
| | - I Fouzas
- Division of Organ Transplantation, Department of Surgery, Aristotle University Medical School, Hippokration General Hospital, Thessaloniki, Greece
| | - A Papagianni
- Department of Nephrology, Aristotle University Medical School, Hippokration General Hospital, Thessaloniki, Greece
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14
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Peng B, Zhuang Q, Yu M, Li J, Liu Y, Zhu L, Ming Y. Comparison of Physical Crossmatch and Virtual Crossmatch to Identify Preexisting Donor-Specific Human Leukocyte Antigen (HLA) Antibodies and Outcome Following Kidney Transplantation. Med Sci Monit 2019; 25:952-961. [PMID: 30712055 PMCID: PMC6369651 DOI: 10.12659/msm.914902] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Background Physical crossmatch (PXM) and virtual crossmatch (VXM) are applied to identify preexisting donor-specific human leukocyte antigen (HLA) antibodies in patients awaiting kidney transplantation. Recently, high-resolution epitope analysis has emerged as a novel strategy for VXM. A retrospective clinical study compared PXM with VXM before kidney transplantation and recipient outcome following transplantation. Material/Methods Between August 2017 and March 2018, 239 patients underwent crossmatching and 94 patients received a donor kidney. A complement-dependent cytotoxicity (CDC) PXM assay and VXM using serological and epitope analysis identified donor-specific antibodies (DSA). Crossmatch results and clinical outcome at 3 months were compared. Results VXM identified serological DSA (sDSA), verified epitope DSA, and total epitope DSA in 74 (31.0%), 39 (16.3%), and 49 (20.5%) cases, respectively. Eleven cases (4.6%) had a positive PXM detected by the CDC assay. Of 94 kidney transplant recipients, 21 had preexisting sDSA but were negative in PXM; there was 1 case of delayed graft function (DGF) and no cases of hyperacute rejection or acute rejection. Of the rest of the 73 recipients who were negative for sDSA, 8 had acute rejection (P=0.253) and 19 had DGF (P=0.037). No significant differences were found in graft survival at 3 months. Conclusions High-resolution epitope analysis identified fewer cases with DSA compared with serological analysis. Because patients with and without sDSA had a similar short-term outcome in the setting of a negative PXM, the presence of preexisting sDSA, determined by VXM, should not be an absolute contraindication for kidney transplantation.
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Affiliation(s)
- Bo Peng
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Quan Zhuang
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Meng Yu
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Junhui Li
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Yun Liu
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Lijun Zhu
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
| | - Yingzi Ming
- The Transplantation Center of The Third Xiangya Hospital, Central South University, Changsha, Hunan, China (mainland).,Engineering and Technology Research Center for Transplantation Medicine of The National Ministry of Health, Changsha, Hunan, China (mainland)
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15
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Histocompatibility leukocyte antigen and organ transplantation: love and hate relationship. Curr Opin Organ Transplant 2018; 23:467-469. [PMID: 29957722 DOI: 10.1097/mot.0000000000000552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Chong AS, Ansari MJ. Heterogeneity of memory B cells. Am J Transplant 2018; 18:779-784. [PMID: 29359404 PMCID: PMC5962275 DOI: 10.1111/ajt.14669] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 12/29/2017] [Accepted: 12/30/2017] [Indexed: 01/25/2023]
Abstract
Potential solid organ transplant recipients broadly sensitized to HLA have long wait times, low transplant rates and poor outcomes. The new kidney allocation system has improved access to the most highly sensitized recipients; however, their long-term outcomes are unknown. Emerging data suggest that memory B cell repertoire is broader than the plasma cell repertoire, therefore, despite refinements in anti-HLA antibody detection technology, donor-specific HLA- specific memory B cells may in fact be present in some, if not most, highly sensitized recipients with no detectable donor-specific antibodies. In addition, new findings have underscored the heterogeneity in memory B cell generation, and in the signals that determine memory versus plasma cell fate during primary antigen encounter, as well as memory B cell differentiation upon antigen reencounter into plasma cells or reentry into germinal centers to subsequently emerge as higher affinity and class-switched plasma cells. Thus, heterogeneity memory B cells generation may affect the efficacy of specific immunomodulation during the recall response. We propose that the ability to quantify donor-specific B cell in transplant recipients is urgently required to provide insights into the mechanisms of sensitization and recall, and for the early detection of acute and chronic AMR.
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Affiliation(s)
- Anita S Chong
- Department of Surgery, Section of Transplantation, University of Chicago, Chicago, IL, USA
- Division of Nephrology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - M Javeed Ansari
- Department of Surgery, Section of Transplantation, University of Chicago, Chicago, IL, USA
- Division of Nephrology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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17
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Direct quantitative measurement of the kinetics of HLA-specific antibody interactions with isolated HLA proteins. Hum Immunol 2018; 79:122-128. [DOI: 10.1016/j.humimm.2017.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/11/2017] [Accepted: 10/26/2017] [Indexed: 02/07/2023]
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18
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19
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Sypek M, Kausman J, Holt S, Hughes P. HLA Epitope Matching in Kidney Transplantation: An Overview for the General Nephrologist. Am J Kidney Dis 2017; 71:720-731. [PMID: 29246419 DOI: 10.1053/j.ajkd.2017.09.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 09/20/2017] [Indexed: 11/11/2022]
Abstract
Rapid changes in tissue-typing technology, including the widespread availability of highly specific molecular typing methods and solid-phase assays for the detection of allele-specific anti-HLA antibodies, make it increasingly challenging to remain up to date with developments in organ matching. Terms such as epitopes and eplets abound in the transplantation literature, but often it can be difficult to see what they might mean for the patient awaiting transplantation. In this review, we provide the historical context for current practice in tissue typing and explore the potential role of HLA epitopes in kidney transplantation. Despite impressive gains in preventing and managing T-cell-mediated rejection and the associated improvements in graft survival, the challenge of the humoral alloresponse remains largely unmet and is the major cause of late graft loss. Describing HLA antigens as a series of antibody targets, or epitopes, rather than based on broad seroreactivity patterns or precise amino acid sequences may provide a more practical and clinically relevant system to help avoid antibody-mediated rejection, reduce sensitization, and select the most appropriate organs in the setting of pre-existing alloantibodies. We explain the systems proposed to define HLA epitopes, summarize the evidence to date for their role in transplantation, and explore the potential benefits of incorporating HLA epitopes into clinical practice as this field continues to evolve toward everyday practice.
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Affiliation(s)
- Matthew Sypek
- Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia; The University of Melbourne, Melbourne, Australia; Department of Nephrology, Royal Children's Hospital, Melbourne, Australia.
| | - Joshua Kausman
- Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia; The University of Melbourne, Melbourne, Australia; Department of Nephrology, Royal Children's Hospital, Melbourne, Australia
| | - Steve Holt
- Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia; The University of Melbourne, Melbourne, Australia
| | - Peter Hughes
- Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia; The University of Melbourne, Melbourne, Australia
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20
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Clinical Outcome of Patients With De Novo C1q-Binding Donor-Specific HLA Antibodies After Renal Transplantation. Transplantation 2017; 101:2165-2174. [PMID: 27653301 DOI: 10.1097/tp.0000000000001487] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND De novo donor specific anti-HLA antibodies (dnDSA) may cause graft loss in renal transplant recipients. The capability to bind the complement may help to stratify the risk for inferior outcomes associated with dnDSA. We developed a modified C1q-binding assay and hypothesized that C1q-binding dnDSA could differentiate between indolent and harmful dnDSA causing antibody-mediated rejection (AMR) and graft loss. METHODS We retrospectively identified 59 renal transplant recipients who developed dnDSA and had serum available and complete follow-up. All patients were analyzed for C1q-binding dnDSA at the time of dnDSA detection, and 1-year later or at time of AMR. AMR-positive patients were also tested 6 to 12 months before the event if IgG dnDSA was present. RESULTS Thirty-seven of 59 dnDSA patients developed AMR during 5.9 ± 3.1 years follow-up. AMR-positive patients had more dnDSA with a significant higher frequency of class I, a higher frequency and a higher mean fluorescence intensity value of C1q-dnDSA at all time-points. Death-censored AMR-free and allograft survivals were significantly lower in C1q-dnDSA patients. In multivariate analysis, C1q-dnDSA was an independent risk factor for AMR. CONCLUSIONS C1q-binding dnDSA is associated with inferior outcomes, yet not in all patients. Nevertheless, C1q-dnDSA was shown to be an independent risk factor of AMR and graft loss and may be a useful tool to stratify the immunological risk for AMR.
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21
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Sypek MP, Hughes P, Kausman JY. HLA epitope matching in pediatric renal transplantation. Pediatr Nephrol 2017; 32:1861-1869. [PMID: 27995324 DOI: 10.1007/s00467-016-3557-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022]
Abstract
Chronic graft loss due to antibody-mediated rejection (AMR) and the difficulty of re-transplanting highly sensitized patients are two of the major long-term challenges in pediatric renal transplantation. Treatments for AMR are often ineffective and desensitization protocols can be a high risk, making prevention a highly appealing strategy. Insights into the structural determinants of humoral alloantigenicity present an exciting opportunity to reassess our current paradigm of tissue matching and potentially preventing these complications. We review the theory behind human leukocyte antigen (HLA) B cell epitopes and the various systems that have been proposed to define them, including eplets. There is a growing body of clinical evidence suggesting that epitope-based tissue matching may be superior to traditional HLA antigen matching at predicting a range of clinical outcomes. However, additional studies are required to better understand the biological relevance of these systems of defining epitopes and their role in pediatric transplantation.
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Affiliation(s)
- Matthew P Sypek
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia. .,Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia. .,University of Melbourne, Melbourne, Australia.
| | - Peter Hughes
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia.,Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
| | - Joshua Y Kausman
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia.,Department of Nephrology, Royal Melbourne Hospital, Melbourne, Australia.,University of Melbourne, Melbourne, Australia.,Murdoch Children's Research Institute, Melbourne, Australia
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22
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Abstract
This overview describes recent developments demonstrating the significance of epitopes in HLA antibody responses and matching for organ transplantation. HLA epitopes are defined by molecular modeling and amino acid comparisons between HLA alleles and the HLAMatchmaker algorithm considers eplets as essential components. Each allele represents a distinct string of eplets and matching is done by aligning donor and recipient strings. Evidence is summarized how mismatched eplet loads affect antibody responses and transplant outcomes. Epitope-based matching has been applied not only to identify acceptable mismatches for sensitized transplant candidates but also to identify more suitably mismatched donors for nonsensitized patients. Three recently proposed theories will further our understanding of the immunogenicity of individual HLA eplets.It has become apparent that epitope-based matching is superior to antigen matching; we should be ready soon to apply this principle in the clinical transplant setting very soon.
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23
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Liu P, Souma T, Wei AZS, Xie X, Luo X, Jin J. Personalized Peptide Arrays for Detection of HLA Alloantibodies in Organ Transplantation. J Vis Exp 2017. [PMID: 28930983 DOI: 10.3791/56278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In organ transplantation, the function and longevity of the graft critically rely on the success of controlling immunological rejection reactivity against human leukocyte antigens (HLA). Histocompatibility guidelines are based on laboratory tests of anti-HLA immunity, which presents either as pre-existing or de novo generated HLA antibodies that constitute a major transplantation barrier. Current tests are built on a single-antigen beads (SAB) platform using a fixed set of ~100 preselected recombinant HLA antigens to probe transplant sera. However, in humans there exist a far greater variety of HLA types, with no two individuals other than identical twins who can share the same combination of HLA sequences. While advanced technologies for HLA typing and direct sequencing can precisely capture any mismatches in DNA sequence between a donor's and recipient's HLA, the SAB assay, due to its limited variety in sequence representation, is unable to precisely detect alloantibodies specifically against the donor HLA mismatches. We sought to develop a complementary method using a different technology to detect and characterize anti-donor HLA antibodies on a personalized basis. The screening tool is a custom peptide array of donor HLA-derived sequences for probing post-transplant sera of the organ recipient to assess the risk for antibody-mediated rejection. On a single array for one donor-recipient pair, up to 600 unique peptides are made based on the donor's HLA protein sequences, each peptide carrying at least one mismatched residue in a 15-amino acid sequence. In our pilot experiments to compare antigen patterns for pre- and post-transplant sera on these arrays, we were able to detect anti-HLA signals with the resolution that also allowed us to pinpoint the immune epitopes involved. These personalized antigen arrays allow high-resolution detection of donor-specific HLA epitopes in organ transplantation.
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Affiliation(s)
- Pan Liu
- Division of Nephrology and Hypertension, and the Center for Kidney Research and Therapeutics at the Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine
| | - Tomokazu Souma
- Division of Nephrology and Hypertension, and the Center for Kidney Research and Therapeutics at the Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine
| | - Andrew Zu-Sern Wei
- Division of Nephrology and Hypertension, and the Center for Kidney Research and Therapeutics at the Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine
| | - Xueying Xie
- School of Biological Sciences and Medical Engineering, Southeast University
| | - Xunrong Luo
- Surgery-Organ Transplantation, Northwestern University Feinberg School of Medicine
| | - Jing Jin
- Division of Nephrology and Hypertension, and the Center for Kidney Research and Therapeutics at the Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine;
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24
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Resse M, Paolillo R, Pellegrino Minucci B, Costa D, Fiorito C, Santangelo M, De Rosa P, Napoli C. Effect of Single Sensitization Event on Human Leukocyte Antigen Alloimmunization in Kidney Transplant Candidates: A Single-Center Experience. EXP CLIN TRANSPLANT 2017; 16:44-49. [PMID: 28661314 DOI: 10.6002/ect.2016.0292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Human leukocyte antigen alloimmunization is caused by exposure to HLA antigens through transfusion, pregnancy, or transplant. Our study objective was to present the rate of positivity of anti-HLA antibody considering the effects of a single sensitization event in kidney transplant candidates at our center. MATERIALS AND METHODS Our study reviewed 606 kidney transplant candidates. Patient sera were analyzed using Luminex xMAP technology. Panel reactive antibody positivity rates and antibody strengths in patients were analyzed according to a single sensitization event. RESULTS Our findings showed 246 patients (40.6%) with a panel reactive antibody > 0, of which 97 (39.4%) were sensitized from a single event, 119 (48.4%) were sensitized by multiple events, and 30 (12.2%) had no known sensitizing event. Considering patients sensitized by a single event with a panel reactive antibody > 0, we found that 25.8% had received transplant only, 49.5% had previous pregnancy only, and 24.7% had received transfusion only. The strength of antibodies was significantly higher in patients with previous transplant procedures than in those with transfusion for HLA-A (P < .01), HLA-B (P < .05), HLA-C (P < .05), HLA-DR (P < .001), HLA-DQ (P < .05), and HLA-DP (P < .05). Similarly, we observed significantly higher median fluorescence intensity values for HLA-A, -DR, -DQ, and -DP loci in patients with a previous transplant procedure versus pregnancy. The strength of antibodies against HLA-DR was significantly higher in patients with a previous pregnancy compared with those with transfusion (P < .01). CONCLUSIONS This study documents the profile of HLA alloimmunization in kidney transplant candidates. In particular, transplant procedures appear to have a greater immunologic impact, followed by pregnancy and transfusion. Our data confirm and are in accordance with those of several studies in which the sensitization events were associated with higher prevalence of anti-HLA antibodies.
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Affiliation(s)
- Marianna Resse
- U.O.C. Division of Immunohematology, Transfusion Medicine and Transplant Immunology, Regional Reference Laboratory of Transplant Immunology, Azienda Ospedaliera Universitaria, Second University of Naples, Naples, Italy
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25
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Abstract
Sensitization to human leukocyte antigens (HLA) in organ transplant patients causes graft rejection, according to the humoral theory of transplantation. Sensitization is almost ubiquitous as anti-HLA antibodies are found in almost all sera of transplant recipients. Advances in testing assays and amino acid sequencing of HLA along with computer software contributed further to the understanding of antibody-antigen reactivity. It is commonly understood that antibodies bind to HLA antigens. With current knowledge of epitopes, it is more accurate to describe that antibodies bind to their target epitopes on the surface of HLA molecular chains. Epitopes are present on a single HLA (private epitope) or shared by multiple antigens (public epitope). The phenomenon of cross-reactivity in HLA testing, often explained as cross-reactive groups (CREGs) of antigens with antibody, can be clearly explained now by public epitopes. Since 2006, we defined and reported 194 HLA class I unique epitopes, including 56 cryptic epitopes on dissociated HLA class I heavy chains, 83 HLA class II epitopes, 60 epitopes on HLA-DRB1, 15 epitopes on HLA-DQB1, 3 epitopes on HLA-DQA1, 5 epitopes on HLA-DPB1, and 7 MICA epitopes. In this paper, we provide a summary of our findings.
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26
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Kramer CSM, Roelen DL, Heidt S, Claas FHJ. Defining the immunogenicity and antigenicity of HLA epitopes is crucial for optimal epitope matching in clinical renal transplantation. HLA 2017; 90:5-16. [DOI: 10.1111/tan.13038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 12/25/2022]
Affiliation(s)
- C. S. M. Kramer
- Department of Immunohematology and Blood Transfusion; Leiden University Medical Centre; Leiden the Netherlands
| | - D. L. Roelen
- Department of Immunohematology and Blood Transfusion; Leiden University Medical Centre; Leiden the Netherlands
| | - S. Heidt
- Department of Immunohematology and Blood Transfusion; Leiden University Medical Centre; Leiden the Netherlands
| | - F. H. J. Claas
- Department of Immunohematology and Blood Transfusion; Leiden University Medical Centre; Leiden the Netherlands
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27
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Usefulness of the ElliPro epitope predictor program in defining the repertoire of HLA-ABC eplets. Hum Immunol 2017; 78:481-488. [PMID: 28336309 DOI: 10.1016/j.humimm.2017.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/08/2017] [Accepted: 03/11/2017] [Indexed: 11/22/2022]
Abstract
HLA matching at the epitope level offers new opportunities to identify suitable donors for transplant patients. The International HLA Epitope Registry (www.Epregistry.com.br) describes for the various HLA loci, repertoires of eplets including those that correspond to epitopes experimentally verified with specific antibodies. There are also many eplets which have remained as theoretical entities because no informative antibodies have been found. Which of them have immunogenic potential or conversely, might be considered as non-epitopes that cannot elicit specific antibody responses? This question is important for the application of epitope-based HLA matching in clinical transplantation. Correct predictions of B-cell epitopes on antigenic proteins are essential to the effective design of microbial vaccines and the development of specific antibodies used in immunotherapy and immunodiagnostics but prediction programs based on structural and physiochemical properties of amino acid residues are generally ineffective. Recent prediction programs based on three-dimensional structures of antigen-antibody complexes are more promising. One such program is called ElliPro developed by Ponomarenko. This report describes studies demonstrating that ElliPro can predict alloantibody responses to HLA-ABC eplets. Antibody-verified eplets have amino acid residues with much higher ElliPro scores than eplets for which no specific antibodies have been found. The latter group includes residues with very low ElliPro scores; they appear to represent eplets that might be classified as non-epitopes. In conclusion, ElliPro offers a new approach to characterize epitope repertoires that are clinically relevant in HLA matching.
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28
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Milongo D, Kamar N, Del Bello A, Guilbeau-Frugier C, Sallusto F, Esposito L, Dörr G, Blancher A, Congy-Jolivet N. Allelic and Epitopic Characterization of Intra-Kidney Allograft Anti-HLA Antibodies at Allograft Nephrectomy. Am J Transplant 2017; 17:420-431. [PMID: 27402017 DOI: 10.1111/ajt.13958] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 06/24/2016] [Accepted: 06/25/2016] [Indexed: 01/25/2023]
Abstract
The reasons for the increased incidence of de novo anti-human leukocyte antibody (HLA) donor-specific antibodies (DSAs) observed after kidney allograft nephrectomy are not fully understood. One advocated mechanism suggests that at graft loss, DSAs are not detected in the serum because they are fixed on the nonfunctional transplant; removal of the kidney allows DSAs to then appear in the blood circulation. The aim of our study was to compare anti-HLA antibodies present in the serum and in the graft at the time of an allograft nephrectomy. Using solid-phase assays, anti-HLA antibodies were searched for in the sera of 17 kidney transplant patients undergoing allograft nephrectomy. No anti-HLA antibodies were detected in the graft if they were not also detected in the serum. Eleven of the 12 patients who had DSAs detected in their sera also had DSAs detected in the grafts. Epitopic analysis revealed that most anti-HLA antibodies detected in removed grafts were directed against the donor. In summary, our data show that all anti-HLA antibodies that were detected in grafts were also detected in the sera. These intragraft anti-HLA antibodies are mostly directed against the donor at an epitopic level but not always at an antigenic level.
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Affiliation(s)
- D Milongo
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France.,Université Paul Sabatier, Toulouse, France
| | - N Kamar
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,INSERM U1043, IFR-BMT, CHU Purpan, Toulouse, France
| | - A Del Bello
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France.,Université Paul Sabatier, Toulouse, France
| | - C Guilbeau-Frugier
- Université Paul Sabatier, Toulouse, France.,Department of Pathology, CHU Toulouse, Toulouse, France
| | - F Sallusto
- Department of Urology and Kidney Transplantation, CHU Toulouse, Toulouse, France
| | - L Esposito
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France
| | - G Dörr
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France.,Université Paul Sabatier, Toulouse, France
| | - A Blancher
- Université Paul Sabatier, Toulouse, France.,Molecular Immunogenetics Laboratory, EA 3034, Faculté de Médecine Purpan, IFR150 (INSERM), Toulouse, France.,Department of Immunology, CHU de Toulouse, Hôpital de Rangueil, Toulouse, France
| | - N Congy-Jolivet
- Université Paul Sabatier, Toulouse, France.,Molecular Immunogenetics Laboratory, EA 3034, Faculté de Médecine Purpan, IFR150 (INSERM), Toulouse, France.,Department of Immunology, CHU de Toulouse, Hôpital de Rangueil, Toulouse, France
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29
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Reynolds BC, Tinckam KJ. Sensitization assessment before kidney transplantation. Transplant Rev (Orlando) 2017; 31:18-28. [DOI: 10.1016/j.trre.2016.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 10/05/2016] [Indexed: 01/28/2023]
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30
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Houp JA, Schillinger KP, Eckstein AJ, Vega RM, Desai NM, Lonze BE, Jackson AM. Casting a smaller net into a bigger donor pool: A single center's experience with the new kidney allocation system. Hum Immunol 2016; 78:49-53. [PMID: 27890719 DOI: 10.1016/j.humimm.2016.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/14/2016] [Accepted: 11/17/2016] [Indexed: 12/27/2022]
Abstract
The new kidney allocation system (KAS) provides additional allocation points for candidates with broad HLA sensitization in an effort to increase transplant rates for this underserved population. Following the implementation of KAS, our center lowered the HLA antibody threshold for listing unacceptable antigens from a cytotoxicity crossmatch level to a flow cytometric crossmatch level increasing Calculated Panel Reactive Antibody (CPRA) values and allocation points, yet restricting acceptable donor HLA phenotypes. As a result, many sensitized candidates were transitioned from 50% to 98% CPRA categories into the 99% CPRA regional share and 100% CPRA national share categories. Exposure to these larger donor pools significantly increased transplantation with compatible donors for 100% CPRA candidates, but regional sharing was not sufficient to increase transplantation rates for our 99% CPRA candidates. Competition within the 100% CPRA cohort identified inequities for 99.99-100.0% CPRA candidates and highlighted the continued need for desensitization therapies to reduce immunological barriers and provide transplant opportunities for the most highly sensitized candidates.
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Affiliation(s)
- Julie A Houp
- Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Karl P Schillinger
- Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Andrew J Eckstein
- Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Renato M Vega
- Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Niraj M Desai
- Department of Surgery, The Johns Hopkins University, Baltimore, MD, USA
| | - Bonnie E Lonze
- Department of Surgery, The Johns Hopkins University, Baltimore, MD, USA
| | - Annette M Jackson
- Department of Medicine, The Johns Hopkins University, Baltimore, MD, USA.
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Duquesnoy RJ. Reflections on HLA Epitope-Based Matching for Transplantation. Front Immunol 2016; 7:469. [PMID: 27965660 PMCID: PMC5124729 DOI: 10.3389/fimmu.2016.00469] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/18/2016] [Indexed: 11/17/2022] Open
Abstract
HLA antibodies are primary causes of transplant rejection; they recognize epitopes that can be structurally defined by eplets. There are many reviews about HLA epitope-based matching in transplantation. This article describes some personal reflections about epitopes including a historical perspective of HLA typing at the antigen and allele levels, the repertoires of antibody-verified HLA epitopes, the use of HLAMatchmaker in determining the specificities of antibodies tested in different assays, and, finally, possible strategies to control HLA antibody responses.
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The Association Between Broad Antigen HLA Mismatches, Eplet HLA Mismatches and Acute Rejection After Kidney Transplantation. Transplant Direct 2016; 2:e120. [PMID: 27990485 PMCID: PMC5142364 DOI: 10.1097/txd.0000000000000632] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 09/14/2016] [Indexed: 12/03/2022] Open
Abstract
Supplemental digital content is available in the text. Background Epitope matching, which evaluates mismatched amino acids within antigen-antibody interaction sites (eplets), may better predict acute rejection than broad antigen matching alone. We aimed to determine the association between eplet mismatches and acute rejection in kidney transplant recipients. Methods The association between eplet mismatches, broad antigen mismatches and acute rejection was assessed using adjusted Cox proportional hazard regression. Model discrimination for acute rejection was evaluated using the area under receiver operating characteristic curves. Results Of the 3,499 kidney transplant recipients from 2006 to 2011, the average (SD) number of broad antigen and eplet mismatches were 3.4 (1.7) and 22.8 (12.2), respectively. Compared with 0 to 2 eplet mismatches, the adjusted hazard ratio (HR) for acute rejection among those with 20 or greater eplet mismatches was 2.16 (95% confidence interval [CI], 1.33-3.52; P = 0.001). The adjusted area under the curve for broad antigen mismatches was 0.58 (95% CI, 0.56-0.61), similar to that for eplet mismatches (HR, 0.59; 95% CI, 0.56-0.61; P = 0.365). In recipients who were considered as low immunological risk (0-2 broad antigen HLA-ABDR mismatch), those with 20 or greater eplet mismatches experienced an increased risk of rejection compared to those with less than 20 mismatches (adjusted HR, 1.85; 95% CI, 1.11-3.08; P = 0.019). Conclusions Increasing number of eplet mismatches is associated with acute rejection in kidney transplant recipients. Consideration of eplet HLA mismatches may improve risk stratification for acute rejection in a selected group of kidney transplant candidates.
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Tambur AR. Hiding in Plain Sight-A New Look at HLA Epitopes: A Case Report. Am J Transplant 2016; 16:3286-3291. [PMID: 27289077 DOI: 10.1111/ajt.13918] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/25/2023]
Abstract
"Epitope matching" has become a buzz word in solid organ transplantation. Its goal is to improve matching between donor and recipient, to minimize risk for antibody-mediated rejection and to reduce sensitization associated with graft failure. Current software allows identification and enumeration of amino acid sequence mismatches in the form of HLA eplets; however, "eplets" and "epitopes" are not interchangeable terms, and the understanding of what contributes to the antigenicity and immunogenicity of HLA B cell epitopes is still very limited and inadequate. In fact, we still do not know what constitutes an HLA epitope or how to define it in a clinically useful way. To allow for judicious implementation of epitope matching, it is critical to explore the full spectrum of factors that affect allorecognition. In exploring antibody-binding patterns, we have uncovered a potential tool-currently hidden in plain sight-that may shed light on some aspects of epitope characteristics.
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Duquesnoy RJ. Should epitope-based HLA compatibility be used in the kidney allocation system? Hum Immunol 2016; 78:24-29. [PMID: 27771385 DOI: 10.1016/j.humimm.2016.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 11/30/2022]
Abstract
The new kidney allocation system (KAS) still applies donor-recipient HLA compatibility mostly at the antigen level and although some four-digit alleles have been included. This system is used to record unacceptable mismatches for sensitized transplant candidates with serum HLA antibodies. Since the reactivities of such antibodies are specifically associated with epitopes rather than HLA antigens, a more scientifically accurate assessment of mismatch acceptability could be based on epitopes. HLA class I and class II epitope specificity analyses can now be readily performed with serum antibody assays with single allele panels. This report describes an epitope-based HLA compatibility system for KAS and involves recipient and donor HLA typing at the four-digit allele level. It focuses on sensitized patients who have serum antibodies specific for HLA epitopes that can be entered as unacceptable mismatches in the transplant candidate database. Newly developed software programs could readily identify compatible HLA types.
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Affiliation(s)
- Rene J Duquesnoy
- University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
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A Novel Method for Anti-HLA Antibody Detection Using Personalized Peptide Arrays. Transplant Direct 2016; 2:e109. [PMID: 27826602 PMCID: PMC5096436 DOI: 10.1097/txd.0000000000000619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/11/2016] [Indexed: 01/02/2023] Open
Abstract
Background HLA mismatches are the primary cause of alloantibody-mediated rejection (AMR) in organ transplantation. To delineate antigenic and immunogenic potentials among individual HLA mismatches, information regarding antibody specificity at the epitope level, instead of the allelic level, is needed. Methods This study explores a direct screening method for HLA linear epitopes in kidney transplant patients. We custom synthesized a large panel of 15-residue HLA peptides in an array format and measured alloantibody reactivity to these peptides from the sera of post and/or pretransplant patients. Two design concepts for the arrays were followed: a standard array of a fixed panel of peptides or personalized arrays. The standard array contains 420 peptides derived from a predetermined set of HLA-DQ allelic antigens based on templates also used in the single-antigen beads assay. Results The array detected distinct antiserum patterns among transplant subjects and revealed epitope levels of specificity largely in accordance with the single-antigen results. Two personalized arrays that each included donor-derived peptides of HLA-A, -B, -C, -DQ, and -DR sequences were separately designed for 2 transplant subjects. The personalized arrays detected de novo antibodies following transplantation. The new method also showed superior sensitivity to a single-antigen assay in one of the cases whose pathological diagnosis of AMR occurred before single-antigen assay could detect antibodies. Conclusions This pilot study proved the feasibility of using personalized peptide arrays to achieve detection of alloantibodies for linear HLA epitopes associated with distinct donor-recipient mismatches. Single or multiple reactive epitopes may occur on an individual HLA molecule, and donor-specific HLA-DQ-reactivity among 5 kidney transplant subjects revealed patterns of shared epitopes.
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36
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Picascia A, Grimaldi V, Napoli C. From HLA typing to anti-HLA antibody detection and beyond: The road ahead. Transplant Rev (Orlando) 2016; 30:187-94. [DOI: 10.1016/j.trre.2016.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 07/07/2016] [Accepted: 07/22/2016] [Indexed: 01/27/2023]
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Abstract
This review paper discusses the impact of de novo donor-specific antibodies (DSA) to donor HLA antigens in kidney transplantation and summarizes the benefits and challenges that exist with DSA monitoring. Post-transplant DSA is associated with worse allograft outcomes and its detection may precede or coincide with clinical, biochemical, and histologic allograft dysfunction. There are no absolute features of DSA testing results that perfectly discriminate between states of disease and health. In a state of antibody-associated graft dysfunction, removal or reduction in DSA may only provide clinical benefit for some. Furthermore, various factors influence test results, and detection of HLA antibodies must be interpreted within the appropriate clinical and laboratory context. The utility of DSA monitoring is further affected by the limited effectiveness of treatment for antibody-mediated rejection. Although DSA monitoring is potentially beneficial in some circumstances, the optimal screening and treatment strategies are still to be defined.
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39
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Web-based ecosystem software for virtual crossmatching in transplant programs. Comput Biol Med 2016; 75:30-7. [PMID: 27240020 DOI: 10.1016/j.compbiomed.2016.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/16/2016] [Accepted: 05/18/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND The compatibilities between donors and recipients are extremely important for evaluating the immunological risks of transplants. One challenge faced by data analysis tools is the transformation of complex data into simple, intuitive, and important information that can be used to resolve contemporary problems. To address this challenge, we developed the EpViX software to perform epitope reactivity analyses and automated epitope virtual crossmatching. EpViX is a facilitator of medical decision-making regarding the identification of the best donor for a high-immunologic risk recipient. The objective of this work is to describe the computational architecture of the EpViX ecosystem (http://www.epvix.com.br). MATERIALS AND METHODS EpViX is a freeware on the web that was developed in the Ruby language. EpViX can be accessed from different platforms, e.g., PCs, tablets, and smartphones. It consists of an ecosystem of tools that are capable of integrating all of the stakeholders who are involved in a transplant process with a deceased donor. RESULTS We successfully developed a program that allows people to work collaboratively and effectively during the donation process by accurately predicting negative crossmatches, saving time and other resources. CONCLUSIONS EpViX represents a significant breakthrough for the organ transplant process and may meet the current needs of transplant programs because it increases the chances of the allocation of low-immunologic risk donors to highly sensitized recipients and assures greater equity among the recipients on a waiting list. EpViX was duly verified and tested in terms of data security. Moreover, usability tests demonstrated that EpViX is an intuitive and easy-to-use tool.
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Antibody-defined epitopes on HLA-DQ alleles reacting with antibodies induced during pregnancy and the design of a DQ eplet map. Hum Immunol 2016; 77:824-831. [PMID: 27374949 DOI: 10.1016/j.humimm.2016.06.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 06/26/2016] [Accepted: 06/27/2016] [Indexed: 11/23/2022]
Abstract
The concept that HLA antibodies recognize epitopes is leading to new approaches of HLA matching at the epitope level. HLA-DQ plays an important role and many studies have identified structurally defined DQ epitopes specifically recognized by antibodies; they have been recorded in the International HLA Epitope Registry http://www.epregistry.com.br but the list is still incomplete. Pregnancy offers an attractive model to study antibody responses to HLA epitopes. The current analysis was done on 42 DQ-reactive post-pregnancy sera tested in binding assays with a panel of DQ heterodimers. The reactivity of 29 sera corresponded fully to the presence of antibody-verified DQA and DQB epitopes recorded in the Registry. Analysis of the remaining 13 sera led to the identification of additional antibody-defined DQB and DQA epitopes. We have designed the first version of an eplet map for DQ alleles which includes antibody-defined DQA and DQB epitopes and shows sequence positions with polymorphic residues which can be used in HLA epitology studies to identify new antibody-defined DQ epitopes.
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Duquesnoy RJ, Hönger G, Hösli I, Marrari M, Schaub S. Detection of newly antibody-defined epitopes on HLA class I alleles reacting with antibodies induced during pregnancy. Int J Immunogenet 2016; 43:200-8. [DOI: 10.1111/iji.12280] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/10/2016] [Accepted: 05/19/2016] [Indexed: 11/30/2022]
Affiliation(s)
- R. J. Duquesnoy
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh Medical Center; Pittsburgh PA USA
| | - G. Hönger
- Immunobiology; University Hospital Basel; Switzerland
| | - I. Hösli
- Department of Obstetrics and Fetomaternal Medicine; University Hospital Basel; Switzerland
| | - M. Marrari
- Thomas E. Starzl Transplantation Institute; University of Pittsburgh Medical Center; Pittsburgh PA USA
| | - S. Schaub
- Transplantation Immunology and Nephrology; University Hospital Basel; Basel Switzerland
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Duquesnoy RJ. The Antibody Response to HLA Mismatch: Putting Together the Pieces of a Puzzle. Am J Transplant 2015; 15:3019-20. [PMID: 26512940 DOI: 10.1111/ajt.13510] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 01/25/2023]
Affiliation(s)
- R J Duquesnoy
- University of Pittsburgh Medical Center, Pittsburgh, PA
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43
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Glotz D, Tambur A. Stratifying Patients Based on Epitope Mismatching: Ready for Primetime? Am J Transplant 2015; 15:2021-2. [PMID: 26095902 DOI: 10.1111/ajt.13343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/03/2015] [Accepted: 04/04/2015] [Indexed: 01/25/2023]
Affiliation(s)
- D Glotz
- Hopital Saint Louis-Nephrology and Transplantation, Paris, France
| | - A Tambur
- Transplant Immunology Laboratory, Chicago, IL
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Duquesnoy RJ, Marrari M, Mulder A. Usefulness of the Nonself-Self Algorithm of HLA Epitope Immunogenicity in the Specificity Analysis of Monospecific Antibodies Induced during Pregnancy. Front Immunol 2015; 6:180. [PMID: 26074914 PMCID: PMC4443772 DOI: 10.3389/fimmu.2015.00180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/31/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND HLAMatchmaker is a program to analyze the epitope specificities of HLA antibodies. It considers each HLA allele as a string of eplets. Intralocus and interlocus comparisons between donor and recipient alleles offer a structural assessment of compatibility and an analysis of allele panel reactivity patterns can generate information about epitope specificities of HLA antibodies. However, HLAMatchmaker cannot always generate conclusive interpretations of reactivity patterns of all monospecific antibodies, which by definition recognize single epitopes. HYPOTHESIS We have therefore developed a new antibody analysis approach that utilizes the nonself-self algorithm of HLA epitope immunogenicity. It is based on the concept that HLA antibodies originate from B-cells with immunoglobulin receptors to self-HLA epitopes on one given allele and which can be activated by epitopes defined by a few nonself residue differences whereas the remainder of the structural epitope of the immunizing allele consists of self residues. METHODS Three human monoclonal class I antibodies from HLA typed women sensitized during pregnancy were tested in Ig-binding assays with single alleles on a Luminex platform. FINDINGS Three new HLA epitopes were identified; they are defined by combinations of nonself- and self-residues for one allele of the antibody producer. CONCLUSION The nonself-self paradigm of HLA epitope immunogenicity offers a second approach to analyze HLA antibody specificities.
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Affiliation(s)
| | - Marilyn Marrari
- University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Arend Mulder
- Leiden University Medical Center, Leiden, Netherlands
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45
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Filippone EJ, Farber JL. Humoral Immune Response and Allograft Function in Kidney Transplantation. Am J Kidney Dis 2015; 66:337-47. [PMID: 25987262 DOI: 10.1053/j.ajkd.2015.03.033] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/22/2015] [Indexed: 12/22/2022]
Abstract
HLA antibodies can damage a kidney transplant. In January 2013, consensus guidelines from The Transplantation Society were published regarding technical aspects of HLA antibody determination, as well as their potential significance in the pre- and posttransplantation periods. During the past 2 years, new studies have been reported, but controversies remain. In this article, these new data related to HLA antibodies in kidney transplantation are reviewed and compared to relevant prior research. Pretransplantation sensitization issues are discussed, including the new more sensitive assays (flow cytometry and solid-phase immunoassays such as Luminex single-antigen bead assays). A positive complement-dependent cytotoxicity crossmatch remains an absolute contraindication to transplantation, although a positive flow cytometry crossmatch is only a relative contraindication. Positivity only by solid-phase assays increases the risk for acute rejection and transplant loss, but acceptable cutoffs are not defined. The sensitizing effect of red blood cell transfusions is substantiated. Following allograft failure, continued immunosuppression decreases the risk of sensitization, whereas overall, the effect of nephrectomy remains uncertain. Regarding the posttransplantation period, new data are available concerning the timing and significance of donor-specific antibodies (DSA). Whereas some centers report DSA appearance after years, others detect DSA within months. The prominence of class II DSA, especially DQ, in the posttransplantation period is noted. The relevance of non-HLA antibodies is discussed, including anti-endothelial cell antibodies, major histocompatibility complex class I chain-related protein A antibodies, and angiotensin II type 1 receptor autoantibodies.
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Affiliation(s)
- Edward J Filippone
- Division of Nephrology, Department of Medicine, Thomas Jefferson University Hospital, Philadelphia, PA.
| | - John L Farber
- Department of Pathology, Thomas Jefferson University Hospital, Philadelphia, PA
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46
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Hahn AB, Bravo-Egana V, Jackstadt JL, Conti DJ, Duquesnoy RJ. HLA-A2 reactive antibodies in a patient who types as HLA-A2: The importance of high resolution typing and epitope-based antibody analysis. Transpl Immunol 2015; 32:141-3. [PMID: 25902331 DOI: 10.1016/j.trim.2015.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/08/2015] [Accepted: 04/14/2015] [Indexed: 11/26/2022]
Abstract
This report describes a case of a highly sensitized patient who had serum antibodies reacting with HLA-A2 but whose phenotype included HLA-A2. The determination of HLA mismatch acceptability at the antigen level was problematic, but high-resolution HLA typing information and epitope-based antibody specificity analysis based on the nonself-self paradigm of HLA epitope immunogenicity have provided a solution. This case supports the concept that HLA typing at the allele level offers a better approach to identifying suitable donors for sensitized patients.
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Affiliation(s)
- A B Hahn
- Transplantation Immunology Laboratory, Department of Surgery, Albany Medical College, Albany, NY, United States.
| | - V Bravo-Egana
- Transplantation Immunology Laboratory, Department of Surgery, Albany Medical College, Albany, NY, United States
| | - J L Jackstadt
- Transplantation Immunology Laboratory, Department of Surgery, Albany Medical College, Albany, NY, United States
| | - D J Conti
- Section of Transplantation, Department of Surgery, Albany Medical Center, Albany, NY, United States
| | - R J Duquesnoy
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
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47
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Filippone EJ, Farber JL. Humoral immunity in renal transplantation: epitopes, Cw and DP, and complement-activating capability - an update. Clin Transplant 2015; 29:279-87. [DOI: 10.1111/ctr.12524] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2015] [Indexed: 01/10/2023]
Affiliation(s)
- Edward J. Filippone
- Division of Nephrology; Department of Medicine; Thomas Jefferson University Hospital; Philadelphia PA USA
| | - John L. Farber
- Department of Pathology; Thomas Jefferson University Hospital; Philadelphia PA USA
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