1
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Nadat F, Clark B. Forming a new perspective: Post-structural approaches to determination of donor compatibility and post-transplant assessment of allograft health. Int J Immunogenet 2024; 51:195-205. [PMID: 38711186 DOI: 10.1111/iji.12675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 03/25/2024] [Indexed: 05/08/2024]
Abstract
The purpose of this review is to encourage a new perspective on the question of donor-recipient compatibility and post-transplant assessment of graft health based on functional measures. The premise is that we should be better sighted on what (and how) the immune system responds toward rather than what is merely there. Continuance of the pursuit of further and better definition of antigens and antibodies is not however discouraged but seen as necessary to improved understanding of the structural correlates of functional immunity. There currently exists, in the opinion of the authors, an opportunity for histocompatibility and immunogenetics laboratories to develop and widen their scope of involvement into these new areas of laboratory activity in support and to the benefit of the transplant programmes they serve.
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Affiliation(s)
- Fatima Nadat
- Functional Assessment of Transplant Immunology Group, St James's University Hospital, Leeds, UK
| | - Brendan Clark
- Functional Assessment of Transplant Immunology Group, St James's University Hospital, Leeds, UK
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2
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Kardol-Hoefnagel T, Senejohnny DM, Kamburova EG, Wisse BW, Reteig L, Gruijters ML, Joosten I, Allebes WA, van der Meer A, Hilbrands LB, Baas MC, Spierings E, Hack CE, van Reekum FE, van Zuilen AD, Verhaar MC, Bots ML, Drop ACAD, Plaisier L, Melchers RCA, Seelen MAJ, Sanders JS, Hepkema BG, Lambeck AJA, Bungener LB, Roozendaal C, Tilanus MGJ, Voorter CE, Wieten L, van Duijnhoven EM, Gelens MACJ, Christiaans MHL, van Ittersum FJ, Nurmohamed SA, Lardy NM, Swelsen W, van der Pant KAMI, van der Weerd NC, Ten Berge IJM, Hoitsma A, van der Boog PJM, de Fijter JW, Betjes MGH, Roelen DL, Claas FH, Bemelman FJ, Senev A, Naesens M, Heidt S, Otten HG. Determination of the clinical relevance of donor epitope-specific HLA-antibodies in kidney transplantation. HLA 2024; 103:e15346. [PMID: 38239046 DOI: 10.1111/tan.15346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
In kidney transplantation, survival rates are still partly impaired due to the deleterious effects of donor specific HLA antibodies (DSA). However, not all luminex-defined DSA appear to be clinically relevant. Further analysis of DSA recognizing polymorphic amino acid configurations, called eplets or functional epitopes, might improve the discrimination between clinically relevant vs. irrelevant HLA antibodies. To evaluate which donor epitope-specific HLA antibodies (DESAs) are clinically important in kidney graft survival, relevant and irrelevant DESAs were discerned in a Dutch cohort of 4690 patients using Kaplan-Meier analysis and tested in a cox proportional hazard (CPH) model including nonimmunological variables. Pre-transplant DESAs were detected in 439 patients (9.4%). The presence of certain clinically relevant DESAs was significantly associated with increased risk on graft loss in deceased donor transplantations (p < 0.0001). The antibodies recognized six epitopes of HLA Class I, 3 of HLA-DR, and 1 of HLA-DQ, and most antibodies were directed to HLA-B (47%). Fifty-three patients (69.7%) had DESA against one donor epitope (range 1-5). Long-term graft survival rate in patients with clinically relevant DESA was 32%, rendering DESA a superior parameter to classical DSA (60%). In the CPH model, the hazard ratio (95% CI) of clinically relevant DESAs was 2.45 (1.84-3.25) in deceased donation, and 2.22 (1.25-3.95) in living donation. In conclusion, the developed model shows the deleterious effect of clinically relevant DESAs on graft outcome which outperformed traditional DSA-based risk analysis on antigen level.
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Affiliation(s)
- Tineke Kardol-Hoefnagel
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Elena G Kamburova
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bram W Wisse
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leon Reteig
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maartje L Gruijters
- Renal Transplant Unit, Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Irma Joosten
- Laboratory Medicine, Laboratory of Medical Immunology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wil A Allebes
- Laboratory Medicine, Laboratory of Medical Immunology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arnold van der Meer
- Laboratory Medicine, Laboratory of Medical Immunology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Luuk B Hilbrands
- Department of Nephrology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Marije C Baas
- Department of Nephrology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Eric Spierings
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
- Central Diagnostic Laboratory (CDL), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelis E Hack
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Franka E van Reekum
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Arjan D van Zuilen
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michiel L Bots
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Adriaan C A D Drop
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Loes Plaisier
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rowena C A Melchers
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A J Seelen
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan Stephan Sanders
- Department of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Bouke G Hepkema
- Department of Laboratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - Annechien J A Lambeck
- Department of Laboratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - Laura B Bungener
- Department of Laboratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - Caroline Roozendaal
- Department of Laboratory Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - Marcel G J Tilanus
- Department of Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Christina E Voorter
- Department of Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Lotte Wieten
- Department of Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Elly M van Duijnhoven
- Department of Internal Medicine, Division of Nephrology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Mariëlle A C J Gelens
- Department of Internal Medicine, Division of Nephrology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Maarten H L Christiaans
- Department of Internal Medicine, Division of Nephrology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Frans J van Ittersum
- Department of Nephrology, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Shaikh A Nurmohamed
- Department of Nephrology, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Neubury M Lardy
- Department of Immunogenetics, Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Wendy Swelsen
- Department of Immunogenetics, Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Karlijn A M I van der Pant
- Renal Transplant Unit, Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Neelke C van der Weerd
- Renal Transplant Unit, Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Ineke J M Ten Berge
- Renal Transplant Unit, Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Andries Hoitsma
- Dutch Organ Transplant Registry (NOTR), Dutch Transplant Foundation (NTS), Leiden, The Netherlands
| | | | - Johan W de Fijter
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michiel G H Betjes
- Department of Nephrology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Dave L Roelen
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | - Frans H Claas
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | - Frederike J Bemelman
- Renal Transplant Unit, Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Aleksandar Senev
- KU Leuven, Department of Microbiology, Immunology and Transplantation, KU Leuven University, Leuven, Belgium
- Histocompatibility and Immunogenetics Laboratory (HILA), Belgian Red Cross-Flanders, Mechelen, Belgium
| | - Maarten Naesens
- KU Leuven, Department of Microbiology, Immunology and Transplantation, KU Leuven University, Leuven, Belgium
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
| | - Sebastiaan Heidt
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | - Henny G Otten
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
- Central Diagnostic Laboratory (CDL), University Medical Center Utrecht, Utrecht, The Netherlands
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3
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Ho QY, Phang CY, Liew IT, Lai ML, Tien CSY, Thangaraju S, Chan M, Kee T. Unrepresented human leucocyte antigen alleles in single-antigen bead assays: A single-centre cohort study. Int J Immunogenet 2023; 50:306-315. [PMID: 37776087 DOI: 10.1111/iji.12639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/25/2023] [Accepted: 09/22/2023] [Indexed: 10/01/2023]
Abstract
Human leucocyte antigen (HLA) alleles may generate antibodies that are undetectable by routine single-antigen beads (SABs) assays if their unique epitopes are unrepresented. We aimed to describe the prevalence and explore the potential impact of unrepresented HLA alleles in standard SAB kits in our cohort. All individuals who had undergone two-field HLA typing (HLA-A/B/C/DRB1/DQA1/-DQB1/-DPA1/-DPB1) from February 2021 to July 2023 were included. Two-field HLA-DRB3/4/5 typing was imputed. Each unrepresented allele was compared with the most similar represented allele in the standard LABScreen, LABScreen ExPlex (One Lambda) and the LIFECODES (Immucor) SAB kits. Differences in eplet expression (HLA Eplet Registry) were identified. Differences in three-dimensional molecular structures were visualized using generated models (SWISS-MODEL). Two-field HLA typing was performed for 116 individuals. Overall, 16.7% of all HLA alleles, found in 36.2% of individuals, were unrepresented by all SAB test kits. Four eplets, found in 12.9% of individuals, were unrepresented in at least 1 SAB kit. Non-Chinese individuals were more likely to have unrepresented HLA alleles and eplets than Chinese individuals. There were differences in HLA allele and eplet representation amongst the different SAB test kits. Use of supplementary SAB test kits may improve HLA allele and eplet representation. Although some HLA alleles were unrepresented, most epitopes were represented in current SAB kits. However, some unrepresented alleles may contain epitopes which may generate undetectable antibodies. Further studies may be needed to investigate the potential clinical impact of these unrepresented alleles and eplets, especially in certain ethnic populations or at-risk individuals.
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Affiliation(s)
- Quan Yao Ho
- Department of Renal Medicine, Singapore General Hospital, Singapore, Singapore
- SingHealth Duke-NUS Transplant Centre, Singapore, Singapore
| | - Chew Yen Phang
- Blood Services Group, Health Sciences Authority, Singapore, Singapore
| | - Ian Tatt Liew
- Department of Renal Medicine, Singapore General Hospital, Singapore, Singapore
- SingHealth Duke-NUS Transplant Centre, Singapore, Singapore
| | - May Ling Lai
- Blood Services Group, Health Sciences Authority, Singapore, Singapore
| | - Carolyn Shan-Yeu Tien
- Department of Renal Medicine, Singapore General Hospital, Singapore, Singapore
- SingHealth Duke-NUS Transplant Centre, Singapore, Singapore
| | - Sobhana Thangaraju
- Department of Renal Medicine, Singapore General Hospital, Singapore, Singapore
- SingHealth Duke-NUS Transplant Centre, Singapore, Singapore
| | - Marieta Chan
- Blood Services Group, Health Sciences Authority, Singapore, Singapore
| | - Terence Kee
- Department of Renal Medicine, Singapore General Hospital, Singapore, Singapore
- SingHealth Duke-NUS Transplant Centre, Singapore, Singapore
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4
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Kleid L, Walter J, Vorstandlechner M, Schneider CP, Michel S, Kneidinger N, Irlbeck M, Wichmann C, Möhnle P, Humpe A, Kauke T, Dick A. Predictive value of molecular matching tools for the development of donor specific HLA-antibodies in patients undergoing lung transplantation. HLA 2023. [PMID: 37068792 DOI: 10.1111/tan.15068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/21/2023] [Accepted: 04/06/2023] [Indexed: 04/19/2023]
Abstract
Molecular matching is a new approach for virtual histocompatibility testing in organ transplantation. The aim of our study was to analyze whether the risk for de novo donor-specific HLA antibodies (dnDSA) after lung transplantation (LTX) can be predicted by molecular matching algorithms (MMA) and their combination. In this retrospective study we included 183 patients undergoing LTX at our center from 2012-2020. We monitored dnDSA development for 1 year. Eplet mismatches (epMM) using HLAMatchmaker were calculated and highly immunogenic eplets based on their ElliPro scores were identified. PIRCHE-II scores were calculated using PIRCHE-II algorithm (5- and 11-loci). We compared epMM and PIRCHE-II scores between patients with and without dnDSA using t-test and used ROC-curves to determine optimal cut-off values to categorize patients into four groups. We used logistic regression with AIC to compare the predictive value of PIRCHE-II, epMM, and their combination. In total 28.4% of patients developed dnDSA (n = 52), 12.5% class I dnDSA (n = 23), 24.6% class II dnDSA (n = 45), and 8.7% both class II and II dnDSA (n = 16). Mean epMMs (p-value = 0.005), mean highly immunogenic epMMs (p-value = 0.003), and PIRCHE-II (11-loci) (p = 0.01) were higher in patients with compared to without class II dnDSA. Patients with highly immunogenic epMMs above 30.5 and PIRCHE-II 11-loci above 560.0 were more likely to develop dnDSA (31.1% vs. 14.8%, p-value = 0.03). The logistic regression model including the grouping variable showed the best predictive value. MMA can support clinicians to identify patients at higher or lower risk for developing class II dnDSA and might be helpful tools for immunological risk assessment in LTX patients.
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Affiliation(s)
- Lisa Kleid
- Laboratory for Immunogenetics, Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
- Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
| | - Julia Walter
- Division of Thoracic Surgery, University Hospital, LMU Munich, Munich, Germany
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany
- Department of Medicine V, University Hospital, LMU Munich, Munich, Germany
| | | | - Christian P Schneider
- Division of Thoracic Surgery, University Hospital, LMU Munich, Munich, Germany
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany
| | - Sebastian Michel
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany
- Department of Cardiac Surgery, University Hospital, LMU Munich, Munich, Germany
| | - Nikolaus Kneidinger
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research (DZL), Munich, Germany
- Department of Medicine V, University Hospital, LMU Munich, Munich, Germany
| | - Michael Irlbeck
- Department of Anesthesiology, University Hospital, LMU Munich, Munich, Germany
| | - Christian Wichmann
- Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
| | - Patrick Möhnle
- Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
| | - Andreas Humpe
- Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
| | - Teresa Kauke
- Division of Thoracic Surgery, University Hospital, LMU Munich, Munich, Germany
- Transplantation Center, University Hospital, LMU Munich, Munich, Germany
| | - Andrea Dick
- Laboratory for Immunogenetics, Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
- Division of Transfusion Medicine, Cell Therapeutics and Haemostaseology, University Hospital, LMU Munich, Munich, Germany
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5
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Tambur AR, Das R. Can We Use Eplets (or Molecular) Mismatch Load Analysis to Improve Organ Allocation? The Hope and the Hype. Transplantation 2023; 107:605-615. [PMID: 36163639 PMCID: PMC9944744 DOI: 10.1097/tp.0000000000004307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/14/2022] [Accepted: 07/03/2022] [Indexed: 11/25/2022]
Abstract
In recent years, there have been calls for implementation of "epitope matching" in deceased-donor organ allocation policies (later changed to "eplet matching"). Emerging data indeed support the use of molecular mismatch load analysis in specific patient groups, with the objective of posttransplant stratification into different treatment arms. For this purpose, the expectation is to statistically categorize patients as low- or high-immune-risk. Importantly, these patients will continue to be monitored' and their risk category, as well as their management, can be adjusted according to on-going findings. However, when discussing deceased donor organ allocation and matching algorithms, where the decision is not modifiable and has lasting impact on outcomes, the situation is fundamentally different. The goal of changing allocation schemes is to achieve the best possible HLA compatibility between donor and recipient. Immunologically speaking, this is a very different objective. For this purpose, the specific interplay of immunogenicity between the donor and any potential recipient must be understood. In seeking compatibility, the aim is not to redefine matching but to identify those mismatches that are "permissible" or' in other words, less immunogenic. In our eagerness to improve transplant outcome, unfortunately, we have conflated the hype with the hope. Terminology is used improperly, and new terms are created in the process with no sufficient support. Here, we call for a cautious evaluation of baseline assumptions and a critical review of the evidence to minimize unintended consequences.
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Affiliation(s)
- Anat R. Tambur
- Comprehensive Transplant Center, Department of Surgery, Northwestern University, Chicago, IL
| | - Rajdeep Das
- Comprehensive Transplant Center, Department of Surgery, Northwestern University, Chicago, IL
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6
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Bezstarosti S, Kramer CSM, Franke-van Dijk MEI, Vergunst M, Bakker KH, Uyar-Mercankaya M, Buchli R, Roelen DL, de Fijter JW, Claas FHJ, Heidt S. HLA-DQ-Specific Recombinant Human Monoclonal Antibodies Allow for In-Depth Analysis of HLA-DQ Epitopes. Front Immunol 2022; 12:761893. [PMID: 35069533 PMCID: PMC8782272 DOI: 10.3389/fimmu.2021.761893] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/06/2021] [Indexed: 12/24/2022] Open
Abstract
HLA-DQ donor-specific antibodies (DSA) are the most prevalent type of DSA after renal transplantation and have been associated with eplet mismatches between donor and recipient HLA. Eplets are theoretically defined configurations of surface exposed amino acids on HLA molecules that require verification to confirm that they can be recognized by alloantibodies and are therefore clinically relevant. In this study, we isolated HLA-DQ specific memory B cells from immunized individuals by using biotinylated HLA-DQ monomers to generate 15 recombinant human HLA-DQ specific monoclonal antibodies (mAb) with six distinct specificities. Single antigen bead reactivity patterns were analyzed with HLA-EMMA to identify amino acids that were uniquely shared by the reactive HLA alleles to define functional epitopes which were mapped to known eplets. The HLA-DQB1*03:01-specific mAb LB_DQB0301_A and the HLA-DQB1*03-specific mAb LB_DQB0303_C supported the antibody-verification of eplets 45EV and 55PP respectively, while mAbs LB_DQB0402_A and LB_DQB0602_B verified eplet 55R on HLA-DQB1*04/05/06. For three mAbs, multiple uniquely shared amino acid configurations were identified, warranting further studies to define the inducing functional epitope and corresponding eplet. Our unique set of HLA-DQ specific mAbs will be further expanded and will facilitate the in-depth analysis of HLA-DQ epitopes, which is relevant for further studies of HLA-DQ alloantibody pathogenicity in transplantation.
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Affiliation(s)
- Suzanne Bezstarosti
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Department of Internal Medicine (Nephrology), Leiden University Medical Center, Leiden, Netherlands
| | - Cynthia S M Kramer
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Manon Vergunst
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | - Kim H Bakker
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Rico Buchli
- Pure Protein LLC, Oklahoma City, OK, United States
| | - Dave L Roelen
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | - Johan W de Fijter
- Department of Internal Medicine (Nephrology), Leiden University Medical Center, Leiden, Netherlands
| | - Frans H J Claas
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Eurotransplant Reference Laboratory, Leiden, Netherlands
| | - Sebastiaan Heidt
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Eurotransplant Reference Laboratory, Leiden, Netherlands
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7
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Johnson AC, Zhang J, Cliff Sullivan H, Wiebe C, Bray R, Gebel H, Larsen CP. hlaR: A rapid and reproducible tool to identify eplet mismatches between transplant donors and recipients. Hum Immunol 2022; 83:248-255. [PMID: 35101308 PMCID: PMC11016307 DOI: 10.1016/j.humimm.2022.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 11/30/2022]
Abstract
Eplet mismatch load, both overall and at the single molecule level, correlates with transplant recipient outcomes. However, precise eplet assessment requires high-resolution HLA typing of both the donor and recipient. Anything less than high-resolution typing requires imputation of HLA types. The currently available methods to identify eplet mismatch are both tedious and demanding. Therefore, we developed a software package and user-friendly web application (hlaR), that simplifies the workflow of eplet analysis, provides functions to impute high-resolution from low-resolution data and calculates both overall and single molecule eplet mismatch for single or multiple donor recipient pairs. Compared to manual assessments using currently available tools (namely, HLAMatchMaker), hlaR resulted in only minimal discrepancy in eplet mismatches (mean absolute difference of 0.56 for class I and 0.86 for class II for unique sum across loci). Additionally, output of the single molecule eplet function compared well to manual calculation, with an average single antigen count increase of 0.19. Importantly, the hlaR tool permits rapid and reproducible imputation and eplet mismatch including comparison between eplet reference tables (e.g. HLAMatchMaker version 2 or 3). Users can import data from a spreadsheet rather than relying on keystroke entry of individual donor and recipient data, thus reducing the risk of data entry errors. The resulting improved scalability of the hlaR tool is highlighted by plotting analysis time against the size of the input dataset. The new hlaR tool can provide eplet mismatch data with a streamlined workflow. With decreased effort from the end user, eplet matching and mismatch load data can be further incorporated into both research and clinical use.
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Affiliation(s)
| | - Joan Zhang
- Department of Surgery, Emory University, United States
| | | | - Chris Wiebe
- Department of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Robert Bray
- Department of Pathology, Emory University, United States
| | - Howard Gebel
- Department of Pathology, Emory University, United States
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8
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Bezstarosti S, Bakker KH, Kramer CSM, de Fijter JW, Reinders MEJ, Mulder A, Claas FHJ, Heidt S. A Comprehensive Evaluation of the Antibody-Verified Status of Eplets Listed in the HLA Epitope Registry. Front Immunol 2022; 12:800946. [PMID: 35154076 PMCID: PMC8831796 DOI: 10.3389/fimmu.2021.800946] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 12/30/2021] [Indexed: 01/09/2023] Open
Abstract
Matching strategies based on HLA eplets instead of HLA antigens in solid organ transplantation may not only increase the donor pool for highly sensitized patients, but also decrease the incidence of de novo donor-specific antibody formation. However, since not all eplets are equally capable of inducing an immune response, antibody verification is needed to confirm their ability to be bound by antibodies, such that only clinically relevant eplets are considered. The HLA Epitope Registry has documented all theoretically defined HLA eplets along with their antibody verification status and has been the foundation for many clinical studies investigating eplet mismatch in transplantation. The verification methods for eplets in the Registry range from polyclonal sera from multi- and uni-parous women to murine and human monoclonal antibodies (mAbs), and antibodies purified by adsorption and elution from sera of HLA immunized individuals. The classification of antibody verification based on different methods for validation is problematic, since not all approaches represent the same level of evidence. In this study, we introduce a classification system to evaluate the level of evidence for the antibody-verified status of all eplets in the HLA Epitope Registry. We demonstrate that for a considerable number of eplets, the antibody-verified status is solely based on polyclonal serum reactivity of multiparous women or on reactivity of murine mAbs. Furthermore, we noted that a substantial proportion of patient sera analyses and human mAb data presented in the HLA Epitope Registry Database has never been published in a peer-reviewed journal. Therefore, we tested several unpublished human HLA-specific mAbs by luminex single antigen beads assay to analyze their HLA reactivity for eplet antibody verification. Although the majority of analyzed mAbs indeed verified their assigned eplets, this was not the case for a number of eplets. This comprehensive overview of evidence for antibody verification of eplets in the HLA Epitope Registry is instrumental for future investigations towards eplet immunogenicity and clinical studies considering antibody-verified eplet mismatch in transplantation and warrants further standardization of antibody verification using high quality data.
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Affiliation(s)
- Suzanne Bezstarosti
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Department of Internal Medicine (Nephrology), Leiden University Medical Center, Leiden, Netherlands
| | - Kim H Bakker
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | - Cynthia S M Kramer
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | - Johan W de Fijter
- Department of Internal Medicine (Nephrology), Leiden University Medical Center, Leiden, Netherlands
| | - Marlies E J Reinders
- Department of Internal Medicine, Erasmus Medical Center Transplantation Institute, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Arend Mulder
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
| | - Frans H J Claas
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Eurotransplant Reference Laboratory, Leiden, Netherlands
| | - Sebastiaan Heidt
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands.,Eurotransplant Reference Laboratory, Leiden, Netherlands
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9
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Implementation of molecular matching in transplantation requires further characterization of both immunogenicity and antigenicity of individual HLA epitopes. Hum Immunol 2021; 83:256-263. [PMID: 34963506 DOI: 10.1016/j.humimm.2021.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 02/08/2023]
Abstract
Over the past decade, high HLA epitope mismatch scores have been associated with inferior transplant outcomes using several tools, of which HLAMatchmaker is most well-known. This software uses theoretically defined polymorphic amino acid configurations, called eplets, for HLA compatibility analysis. Although consideration of eplet mismatch loads has potential for immunological risk stratification of transplant patients, the use of eplet matching in organ allocation algorithms is hindered by lacking knowledge of the immunogenicity of individual eplets, and the possibility that single mismatched amino acids, rather than complete eplets, are responsible for HLA antibody induction. There are several approaches to define eplet immunogenicity, such as antibody verification of individual eplets, and data-driven approaches using large datasets that correlate specific eplet mismatches to donor specific antibody formation or inferior transplant outcomes. Data-driven approaches can also be used to define whether single amino acid mismatches may be more informative than eplet mismatches for predicting HLA antibody induction. When using epitope knowledge for the assignment of unacceptable antigens, it important to realize that alleles sharing an eplet to which antibodies have formed are not automatically all unacceptable since multiple contact sites determine the binding strength and thus biological function and pathogenicity of an antibody, which may differ between reactive alleles. While the future looks bright for using HLA epitopes in clinical decision making, major steps need to be taken to make this a clinical reality.
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10
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Geffard E, Boussamet L, Walencik A, Delbos F, Limou S, Gourraud PA, Vince N. HLA-EPI: A new EPIsode in exploring donor/recipient epitopic compatibilities. HLA 2021; 99:79-92. [PMID: 34862850 PMCID: PMC9545700 DOI: 10.1111/tan.14505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/16/2021] [Accepted: 12/02/2021] [Indexed: 11/30/2022]
Abstract
The HLA system plays a pivotal role both in transplantation and immunology. While classical HLA genotypes matching is made at the allelic level, recent progresses were developed to explore antibody–antigen recognition by studying epitopes. Donor to recipient matching at the epitopic level is becoming a trending topic in the transplantation research field because anti‐HLA antibodies are epitope‐specific rather than allele‐specific. Indeed, different HLA alleles often share common epitopes. We present the HLA‐Epi tool (hla.univ-nantes.fr) to study an HLA genotype at the epitope level. Using the international HLA epitope registry (Epregistry.com.br) as a reference, we developed HLA‐Epi to easily determine epitopic and allelic compatibility levels between several HLA genotypes. The epitope database covers the most common HLA alleles (N = 2976 HLA alleles), representing more than 99% of the total observed frequency of HLA alleles. The freely accessible web tool HLA‐Epi calculates an epitopic mismatch load between different sets of potential recipient‐donor pairs at different resolution levels. We have characterized the epitopic mismatches distribution in a cohort of more than 10,000 kidney transplanted pairs from European ancestry, which showed low number of epitopic mismatches: 56.9 incompatibilities on average. HLA‐Epi allows the exploration of epitope pairing matching to better understand epitopes contribution to immune responses regulation, particularly during transplantation. This free and ready‐to‐use bioinformatics tool not only addresses limitations of other related tools, but also offers a cost‐efficient and reproducible strategy to analyze HLA epitopes as an alternative to HLA allele compatibility. In the future, this could improve sensitization prevention for allograft allocation decisions and reduce the risk of alloreactivity.
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Affiliation(s)
- Estelle Geffard
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France
| | - Léo Boussamet
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France
| | - Alexandre Walencik
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France.,Laboratoire d'Histocompatibilité et d'Immunogénétique, EFS Centre - Pays de la Loire, Nantes, France
| | - Florent Delbos
- Laboratoire d'Histocompatibilité et d'Immunogénétique, EFS Centre - Pays de la Loire, Nantes, France
| | - Sophie Limou
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France.,Département Informatique et Mathématiques, Ecole Centrale de Nantes, Nantes, France
| | - Pierre-Antoine Gourraud
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France
| | - Nicolas Vince
- Centre de Recherche en Transplantation et Immunologie, Université de Nantes, CHU Nantes, Inserm, Nantes, France
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11
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Ehlayel A, Simms KJA, Ashoor IF. Emerging monitoring technologies in kidney transplantation. Pediatr Nephrol 2021; 36:3077-3087. [PMID: 33523298 DOI: 10.1007/s00467-021-04929-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/22/2020] [Accepted: 01/06/2021] [Indexed: 11/27/2022]
Abstract
Non-invasive technologies to monitor kidney allograft health utilizing high-throughput assays of blood and urine specimens are emerging out of the research realm and slowly becoming part of everyday clinical practice. HLA epitope analysis and eplet mismatch score determination promise a more refined approach to the pre-transplant recipient-donor HLA matching that may lead to reduced rejection risk. High-resolution HLA typing and multiplex single antigen bead assays are identifying potential new offending HLA antibody subtypes. There is increasing recognition of the deleterious role non-HLA antibodies play in post-transplant outcomes. Donor-derived cell-free DNA detected by next-generation sequencing is a promising biomarker for kidney transplant rejection. Multi-omics techniques are shedding light on discrete genomic, transcriptomic, proteomic, and metabolomic signatures that correlate with and predict allograft outcomes. Over the next decade, a comprehensive approach to optimize kidney matching and monitor transplant recipients for acute and chronic graft dysfunction will likely involve a combination of those emerging technologies summarized in this review.
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Affiliation(s)
- Abdulla Ehlayel
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA
| | - K'joy J A Simms
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA
| | - Isa F Ashoor
- Children's Hospital New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA.
- Department of Pediatrics, LSU Health New Orleans, 200 Henry Clay Ave, New Orleans, LA, 70118, USA.
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12
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Lemieux W, Mohammadhassanzadeh H, Klement W, Daniel C, Sapir-Pichhadze R. Matchmaker, matchmaker make me a match: Opportunities and challenges in optimizing compatibility of HLA eplets in transplantation. Int J Immunogenet 2021; 48:135-144. [PMID: 33426788 DOI: 10.1111/iji.12525] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/12/2020] [Accepted: 12/20/2020] [Indexed: 12/20/2022]
Abstract
The development of donor-specific antibodies (DSAs) is a major complication in transplantation, which is associated with inferior graft survival, impaired quality of life, and increased healthcare costs. DSA develop upon recognition of nonself HLA by the recipient's immune system. HLA molecules contain epitopes, which are the surface regions of HLA molecules recognized by antibodies. HLAMatchmaker is an algorithm for assessing donor:recipient HLA compatibility at the level of structurally defined HLA targets called eplets. The consideration of eplets, rather than the whole HLA molecule, could offer some advantages when classifying the immune risk associated with particular donor:recipient pairs. Assessing compatibility at the level of HLA eplets could decrease misclassification of post-transplant immune risk by improving specificity, when antibodies are confirmed to be directed against donor eplets missing from the recipient's repertoire of eplets. Consideration of eplets may also increase the sensitivity of immune risk assessment, when identifying mismatched eplets that could give rise to new, not previously detected, donor-specific antibodies post-transplant. Eplet matching can serve as a rational strategy for immune risk mitigation. Herein, we review the evolution of HLA (in) compatibility assessment for organ allocation. We outline challenges in the implementation of eplet-based donor:recipient matching, including unavailability of allele-level donor genotypes for 11 HLA loci at the time of organ allocation and difficulty in assessing the hierarchy of immune risk associated with particular HLA eplet mismatches. Opportunities to address some of the current shortcomings of donor genotyping and HLAMatchmaker are also discussed. While there is a demonstrated benefit in the application of HLAMatchmaker for donor: recipient HLA (in)compatibility assessment, evolving long-read genotyping methods, compilation of large data sets with allele-level genotypes, and standardization of methods to verify eplets as determinants of immune-mediated injuries are required before HLA eplet matching is implemented in organ allocation to improve upon transplant outcomes.
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Affiliation(s)
- William Lemieux
- Centre for Outcomes Research and Evaluation (CORE), Research Institute of McGill University Health Centre, Montréal, QC, Canada
| | - Hossein Mohammadhassanzadeh
- Centre for Outcomes Research and Evaluation (CORE), Research Institute of McGill University Health Centre, Montréal, QC, Canada
| | - William Klement
- Centre for Outcomes Research and Evaluation (CORE), Research Institute of McGill University Health Centre, Montréal, QC, Canada.,Canadian Blood Services, Ottawa, Ontario, Canada
| | - Claude Daniel
- Division of Hematology, McGill University Health Centre, Montréal, QC, Canada
| | - Ruth Sapir-Pichhadze
- Centre for Outcomes Research and Evaluation (CORE), Research Institute of McGill University Health Centre, Montréal, QC, Canada.,Division of Nephrology and the Multi-Organ Transplant Program, Royal Victoria Hospital, McGill University Health Centre, Montréal, QC, Canada.,Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, QC, Canada
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13
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Eplet-based virtual PRA increases transplant probability in highly-sensitized patients. Transpl Immunol 2021; 65:101362. [PMID: 33434652 DOI: 10.1016/j.trim.2021.101362] [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: 09/08/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND The reduced access of highly-sensitized (HS) patients to kidney transplantation (KTx) is one of the major challenges for transplant community. Therefore, the aim of our study was to estimate the impact of three different vPRA calculations, assessed traditionally and using eplet-based analysis, in donor offers. METHODS At 01-01-2020, 157 HS patients are waitlisted for deceased donor KTx and were included in this study. Total vPRA (vPRAt) was calculated considering all patient allosensitization history, using 1 k MFI cut-off. Current vPRA (vPRAc) refers only to the last year SAB assays, using 1 k MFI cut-off. For eplet vPRA (vPRAe) every SAB assay was analyzed by HLAMatchmaker and HLAfusion software. Matching runs have been performed taking vPRA calculation as unacceptable antigens (UAs). RESULTS All patients had at least one previous sensitizing event and patients with 100% vPRA were predominantly candidates for retransplantation (P < 0.001), had higher PRA-CDC (P < 0.001), and longer dialysis vintage waiting time (P < 0.001). Inter-group movement analysis between vPRA measures showed that 70 (45%), 124 (79%) and 80 (51%) patients were reclassified to a lower group when considering vPRAt to vPRAc, vPRAt to vPRAe and vPRAc to vPRAe, respectively. The median percentage of change in estimated number of match runs needed for 95% probability of finding an acceptable donor was significantly more pronounced by increasing vPRAt intervals, when considering the reclassification from vPRAt to vPRAe (P < 0.001) or vPRAc to vPRAe (P = 0.045), while from vPRAt to vPRAc it was not (P = 0.899). CONCLUSIONS Our study demonstrated that the use of total or current vPRA calculations are impairing HS patients, by decreasing transplant probability, leading to dramatically longer waiting times, when compared to eplet based vPRA.
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14
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Schawalder L, Hönger G, Kleiser M, van Heck MR, van de Pasch LAL, Vendelbosch S, Rozemuller EH, Schaub S. Development of an immunogenicity score for HLA-DQ eplets: A conceptual study. HLA 2020; 97:30-43. [PMID: 33068062 PMCID: PMC7756751 DOI: 10.1111/tan.14110] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/01/2020] [Accepted: 10/10/2020] [Indexed: 12/27/2022]
Abstract
Eplets are defined as distinct amino acid configurations on the surface of HLA molecules. The aim of this study was to estimate the immunogenicity of HLA‐DQ eplets in a cohort of 221 pregnancies with HLA‐DQ mismatches. We defined the immunogenicity of an eplet by the frequency of antibody responses against it. Around 90% of all listed DQB1 or DQA1 eplets were at least five times mismatched and thus included for the calculation of their immunogenicity. The DQB1 eplets with the five highest immunogenicity scores were 55PP, 52PR, 52PQ, 85VG and 45EV; 25% of all DQB1 eplets were not reacting. The DQA1 eplets with the five highest immunogenicity scores were 25YS, 47QL, 55RR, 187T and 18S; 17% of all DQA1 eplets were not reacting. The immunogenicity score had a slightly higher area under the curve to predict development of child‐specific antibodies than various molecular mismatch scores (eg, eplet mismatch load, amino acid mismatch load). Overlapping eplets were identified as a barrier to unambiguously assign the immunogenicity score based on HLA antibody reaction patterns. In this conceptual study, we explored the immunogenicity of HLA‐DQ eplets and created a map of potentially immunogenic regions on HLA‐DQ molecules, which requires validation in clinical transplant cohorts.
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Affiliation(s)
- Lara Schawalder
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - Gideon Hönger
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.,Transplantation Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland.,HLA-Diagnostics and Immungenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland
| | - Marc Kleiser
- HLA-Diagnostics and Immungenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland
| | | | | | | | | | - Stefan Schaub
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.,Transplantation Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland.,HLA-Diagnostics and Immungenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland
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