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Ladowski JM, Chapman H, DeLaura I, Anwar IJ, Yoon J, Chen Z, Clark A, Chen D, Knechtle S, Jackson A, Rogers B, Kwun J. Allosensitisation in NHP results in cross-reactive anti-SLA antibodies not detected by a lymphocyte-based flow cytometry crossmatch. HLA 2024; 104:e15599. [PMID: 39041289 PMCID: PMC11268796 DOI: 10.1111/tan.15599] [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: 04/29/2024] [Revised: 07/01/2024] [Accepted: 07/04/2024] [Indexed: 07/24/2024]
Abstract
Xenotransplantation is a potential option for individuals for whom an acceptable human allograft is unavailable. Individuals with broadly reactive HLA antibodies due to prior exposure to foreign HLA are potential candidates for a clinical xenotransplant trial. It remains controversial if allosensitisation results in the development of cross-reactive antibodies against SLA. This may require increased histocompatibility scrutiny for highly sensitised individuals prior to enrollment in a clinical trial. Serum samples were obtained from non-human primates sensitised via serial skin transplantation from maximally MHC-mismatched donor, as reported. Sera from pre- and post-allosensitisation timepoints were assessed in a flow crossmatch (FXM) for IgM and IgG binding to pig splenocytes with or without red blood cell adsorption. Xenoreactive antibodies were eluted from pig splenocytes and screened on a single antigen HLA bead assay. A MHC Matchmaker algorithm was developed to predict potential conserved amino acid motifs among the pig, NHP, and human. Our sensitised NHP model was used to demonstrate that allosensitisation does not result in an appreciable difference in xenoreactive antibody binding in a cell-based FXM. However, antibody elution and screening on single antigen HLA beads suggest the existence of potential cross-reactive antibodies against SLA. The cross-reactive IgG after allosensitisation were predicted by comparing the recipient Mamu alleles against its previous allograft donor Mamu alleles and the donor pig SLA alleles. Our study suggests that allosensitisation could elevate cross-reactive antibodies, but a more sensitive assay than a cell-based FXM is required to detect them. The MHC Matchmaker algorithm was developed as a potential tool to help determine amino acid motif conservation and reactivity pattern.
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Affiliation(s)
- Joseph M. Ladowski
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Henry Chapman
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Isabel DeLaura
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Imran J. Anwar
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Janghoon Yoon
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Zheng Chen
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Adella Clark
- Clinical Transplantation Immunology Laboratory, Duke University School of Medicine, Durham, NC
| | - DongFeng Chen
- Clinical Transplantation Immunology Laboratory, Duke University School of Medicine, Durham, NC
| | - Stuart Knechtle
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Annette Jackson
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Clinical Transplantation Immunology Laboratory, Duke University School of Medicine, Durham, NC
| | - Bruce Rogers
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Jean Kwun
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
- Department of Surgery, Duke University School of Medicine, Durham, NC
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Doxiadis I, Loeffler-Wirth H, Lachmann N, Lehmann C. A Short History of B-Cell HLA Epitopes. Transfus Med Hemother 2024; 51:152-157. [PMID: 38867808 PMCID: PMC11166405 DOI: 10.1159/000538447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 03/19/2024] [Indexed: 06/14/2024] Open
Abstract
Background HLA epitopes are currently in the focus of transplantation immunogenetics. The main reason is the complexity of the HLA system with >38,000 alleles, the number of which increases steadily. These alleles are determined by the current state-of-the art typing methods like second- and third-generation sequencing. Screening for HLA antibodies is hampered by the lack of specific target beads with all possible alleles described. Summary A way to circumvent the problem is to define HLA epitopes. The number of antibody-confirmed epitopes, on the other hand, was found to be 72 for HLA class I and 74 for HLA class II. Here, we elaborate on the current knowledge on these HLA epitopes. Absolute definitions of these structures are not yet available. Key Messages Making use of eplets is a comparable way allowing statistical analyses. However, one should keep in mind that the results obtained are approximative or perhaps better associative. Continuous collaboration is needed for the full understanding of the HLA epitopes. The reactivity toward epitopes remains patient-specific.
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Affiliation(s)
- Ilias Doxiadis
- Laboratory for Transplantation Immunology, University Hospital Leipzig, Faculty of Medicine Leipzig, Leipzig, Germany
| | - Henry Loeffler-Wirth
- Interdisciplinary Centre for Bioinformatics, IZBI, Leipzig University, Leipzig, Germany
| | - Nils Lachmann
- Institute for Transfusion Medicine, H and I Laboratory, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Claudia Lehmann
- Laboratory for Transplantation Immunology, University Hospital Leipzig, Faculty of Medicine Leipzig, Leipzig, Germany
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Dos Reis Ferreira C, da Silva Fernandes VM, Tafulo SCR, Cerqueira A, Rocha ACB, Nunes ATPM, Ferreira IPCN, Santos MJC, Pinho ATMT, Tavares IC, Guerra MMBB, Norton SMMS. Repeated human leukocyte antigens eplets, importance of typing the partner. Transpl Immunol 2024; 84:102049. [PMID: 38729449 DOI: 10.1016/j.trim.2024.102049] [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: 04/05/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024]
Abstract
INTRODUCTION Antibody-mediated rejection (AMR) is the most common cause of immune-mediated allograft failure after kidney transplant and impacts allograft survival. Previous sensitization is a major risk factor for development of donor specific antibodies (DSA). AMR can have a wide range of clinical features such as impaired kidney function, proteinuria/hypertension or can be subclinical. HLA molecules have specific regions of antigens binding antibodies called epitopes and eplets are considered essential components responsible for immune recognition. We present a patient with subclinical AMR 1 week post transplantation. CASE REPORT A 48-year-old, caucasian woman with end-stage kidney disease (ESKD) secondary to autosomal dominant polycystic kidney disease (ADPKD) on peritoneal dialysis was registered in deceased donor waitlist. She was a hypersensitized patient from 3 prior pregnancies with a calculated panel reactive antibody of 93,48%. She was transplanted through kidney paired exchange donation with no evidence of DSA pre transplantation. Surgery and post-op were unremarkable with excellent and immediate graft function. Per protocol DSA levels on the 5th day was DR1 of 3300 MFI, with an increase in MFI by day 13 with 7820 MFI and a new B41 1979MFI. Allograft kidney biopsy findings were diagnostic of AMR and she was treated with immunoglobulin and plasmapheresis. As early onset AMR post transplantation was observed an anamnestic response was hypothesized from a previous exposure to allo-HLA. We decided to type her husband, her son's father, which was presented with DSA. Mismatch eplet analysis revealed a shared 41 T and 67LQ eplets between the donor and husband, responsible for the reactivity and new HLA class I B41 and HLA class II DR1 DSA, respectively. DISCUSSION Shared eplets between the patient husband and donor was responsible for the alloimmune response and early development of DSAs. This case highlights the importance of early monitoring DSA levels in highly sensitized patients after transplant in order to promptly address and lower inflammatory damage. Mismatch eplet analysis can provide a thorough and precise evaluation of immune compatibility providing a useful technique to immune risk stratification, donor selection and post-transplant immunosuppressive therapy and monitoring.
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Affiliation(s)
| | | | - Sandra Cristina Ribeiro Tafulo
- Centro de Sangue e da Transplantação do Porto, IPST, Porto, Portugal; Unit for Multidisciplinary Research in Biomedicine (UMIB), ICBAS, Porto, Portugal
| | - Ana Cerqueira
- Nephrology Department, Centro Hospitalar Universitário de São João, Porto, Portugal; Nephrology & Infectious Diseases R & D Group, i3S-Instituto de Investigação e Inovação em Saúde, INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
| | | | | | - Inês Passos Castro Neto Ferreira
- Nephrology Department, Centro Hospitalar Universitário de São João, Porto, Portugal; Nephrology & Infectious Diseases R & D Group, i3S-Instituto de Investigação e Inovação em Saúde, INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
| | | | | | - Isabel Cristina Tavares
- Nephrology Department, Centro Hospitalar Universitário de São João, Porto, Portugal; Nephrology & Infectious Diseases R & D Group, i3S-Instituto de Investigação e Inovação em Saúde, INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
| | | | - Susana Maria Moreira Sampaio Norton
- Nephrology Department, Centro Hospitalar Universitário de São João, Porto, Portugal; Nephrology & Infectious Diseases R & D Group, i3S-Instituto de Investigação e Inovação em Saúde, INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Portugal; Faculty of Medicine - University of Porto, Portugal
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Vu TTM, Zhang A, Wang R, Mathew S, Abeywardana T, Beltran-Lemus M, Ma V, Libby M, Thomas D, Wakefield I, Zhu Q, Lowe D, Pei R. Using single antigen specificity magnetic beads for the isolation of specific antibodies against HLA antigens. HLA 2024; 103:e15490. [PMID: 38634568 DOI: 10.1111/tan.15490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 03/14/2024] [Accepted: 04/05/2024] [Indexed: 04/19/2024]
Abstract
The presence of multiple donor-specific antibodies (DSAs) targeting HLA antigens poses a challenge to transplantation. Various techniques, including the use of recombinant cell lines and crossmatch cells have been developed to isolate DSAs. To simplify the extraction of HLA-specific DSAs from complex sera, we introduced magnetic beads with single HLA specificity (MagSort). Sera were treated with MagSort, allowing HLA-specific antibodies to bind to the beads, and these specific antibodies were subsequently eluted. MagSort beads, coated with 59 different HLA variants, underwent testing through 1329 adsorption/elution processes, demonstrating their effectiveness and specificity in adsorbing and eluting HLA-specific antibodies. The MagSort method proves comparable to the cell method, showing similar isolated antibody binding patterns. The isolated antibody binding patterns from MagSort reveal both known eplets and unknown patterns, suggesting its utility for eplet discovery. Additionally, MagSort proved effective in extracting signals for flow cytometry cross-matching, offering a means to assess the binding capability of isolated antibodies against specific donor cells.
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Affiliation(s)
- Tri T M Vu
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Aiwen Zhang
- Allogen Laboratories, Cleveland Clinic, Cleveland, Ohio, USA
| | - Ronald Wang
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Shalu Mathew
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Tharindumala Abeywardana
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Marissa Beltran-Lemus
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Vincent Ma
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Mary Libby
- Allogen Laboratories, Cleveland Clinic, Cleveland, Ohio, USA
| | - Dawn Thomas
- Allogen Laboratories, Cleveland Clinic, Cleveland, Ohio, USA
| | - Ito Wakefield
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Quansheng Zhu
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - David Lowe
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
| | - Rui Pei
- Department of Research and Development, One Lambda, Inc. (A Part of Thermo Fisher Scientific Inc.), West Hills, California, USA
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Doxiadis I, Lehmann C. External proficiency testing exercises: challenges and opportunities. Front Genet 2024; 15:1304312. [PMID: 38404667 PMCID: PMC10884168 DOI: 10.3389/fgene.2024.1304312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/31/2024] [Indexed: 02/27/2024] Open
Affiliation(s)
- Ilias Doxiadis
- Institute for Transfusion Medicine, University Hospital of Leipzig, Leipzig, Germany
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Tafulo S, Osório E, Mendes C, Liwski R. Complement-dependent cytotoxicity crossmatch in solid organ transplantation: The gold standard or golden history? Hum Immunol 2024; 85:110734. [PMID: 38030522 DOI: 10.1016/j.humimm.2023.110734] [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: 09/20/2023] [Revised: 11/19/2023] [Accepted: 11/20/2023] [Indexed: 12/01/2023]
Abstract
Complement-dependent cytotoxicity crossmatch (CDC-XM) has been considered for many years the standard of practice for determining compatibility in solid organ transplantation (SOT). However, as this method is laborious, time intensive and lacks sensitivity and specificity, it has been replaced in many laboratories worldwide by flow cytometry crossmatch (FCXM) and/or virtual crossmatch (vXM). With this study we intend to show the relevance of performing CDC-XM in the era of virtual crossmatching. We retrospectively analyzed 1,007 consecutive T and B cell deceased donor (DD) CDC-XMs performed in parallel using non-treated and dithiothreitol (DTT) treated sera between May 2022 and January 2023 in waitlisted patients with no donor specific antibodies (DSA) against HLA-A, B and/or DR antigens. Thirty five of 1,007 (3.5%) T cell crossmatches and 132 of 1,007 (13.1%) B cell crossmatches were positive with non-treated sera. Correlation with the vXM demonstrated no DSA in any of the positive T cell crossmatches. DSA were also absent in 126/132 positive B cell crossmatches, indicating a high rate of false positive CDC-XM. Indeed, only 4/35 T cell and 13/132 B cell CDC-XM remained positive after treatment with DTT, confirming that false positive reactivity with non-treated sera is high. Class I HLA DSA against C locus antigens were present in 17/1,007 T cell crossmatches and none were detected by CDC-XM (sensitivity = 0%). Similarly, only 6/77 B cell crossmatches with DSA targeting HLA-C, DQ and/or DP antigens were CDC-XM positive (sensitivity = 7.8%). Furthermore, only 4/6 positive B cell CDC-XM were confirmed to have complement binding potential using the C1q assay, suggesting additional false positive reactivity in 2/6 of the positive CDC-XM. Our study demonstrates that CDC-XM exhibits poor sensitivity, high false positive reactivity (especially without DTT treatment) and does not meaningfully contribute to pre-transplant compatibility testing in the context of vXM based allocation. Furthermore, the use of CDC-XM can unnecessarily delay or even prevent safe and appropriate transplant allocation.
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Affiliation(s)
- Sandra Tafulo
- Centro de Sangue e da Transplantação do Porto, Instituto Português do Sangue e da Transplantação, Porto, Portugal; UMIB - Unit for Multidisciplinary Research in Biomedicine, ICBAS - School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal
| | - Ermelinda Osório
- Centro de Sangue e da Transplantação do Porto, Instituto Português do Sangue e da Transplantação, Porto, Portugal
| | - Cecília Mendes
- Centro de Sangue e da Transplantação do Porto, Instituto Português do Sangue e da Transplantação, Porto, Portugal
| | - Robert Liwski
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
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Balas A, Sanchez-Gordo F, Moreno-Hidalgo MÁ, García-Sánchez F, Vicario JL. Characterization of the novel HLA-DRB1*10:38 allele, showing an extended cytoplasmic tail. HLA 2024; 103:e15263. [PMID: 37853624 DOI: 10.1111/tan.15263] [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: 09/28/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Abstract
Sequence and expression analysis of the HLA-DRB1*10:38 allele.
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Affiliation(s)
- Antonio Balas
- Histocompatibilidad, Centro de Transfusión de la Comunidad de Madrid, Madrid, Spain
| | | | | | - Félix García-Sánchez
- Histocompatibilidad, Centro de Transfusión de la Comunidad de Madrid, Madrid, Spain
| | - José L Vicario
- Histocompatibilidad, Centro de Transfusión de la Comunidad de Madrid, Madrid, Spain
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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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Lima ACM, Getz J, do Amaral GB, Loth G, Funke VAM, Nabhan SK, Petterle RR, de Marco R, Gerbase-DeLima M, Pereira NF, Bonfim C, Pasquini R. Donor-specific HLA antibodies are associated with graft failure and delayed hematologic recovery after unrelated donor hematopoietic cell transplantation. Transplant Cell Ther 2023:S2666-6367(23)01298-8. [PMID: 37220839 DOI: 10.1016/j.jtct.2023.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND Graft failure (GF) is one of the major concerns after allogeneic hematopoietic cell transplantation (allo-HCT) and remains a significant cause of morbidity and mortality. Although earlier reports have associated the presence of donor-specific HLA antibodies (DSAs) with increased risk of GF after unrelated donor allo-HCT, recent studies have failed to confirm this association. OBJECTIVE We sought to validate the presence of DSAs as a risk factor for GF and hematologic recovery in the unrelated donor allo-HCT setting. STUDY DESIGN We retrospectively evaluated 303 consecutive patients who underwent their first unrelated donor allo-HCT at our institution from January 2008 to December 2017. DSA evaluation was performed using 2 Single Antigen Beads (SAB) assays, DSA titration with 1:2, 1:8, and 1:32 dilutions, C1q-binding assay, and absorption/elution protocol to assess possible false-positive DSA reactivity. The primary endpoints were neutrophil and platelet recovery and GF, whereas the secondary endpoint was overall survival. Multivariable analyses were performed using Fine-Gray competing risks regression or Cox proportional hazards regression models. RESULTS The median patient age was 14 years (range, 0-61 years), 56.1% were male, and 52.5% were transplanted for nonmalignant diseases. Eleven patients (3.63%) were DSA-positive. Of them, 10 had preexisting DSAs, and one showed post-transplant de novo DSA. Nine patients had 1 DSA, 1 had 2 DSAs, and 1 had 3 DSAs, with a median MFI of 4334 (range, 588-20,456) and 3581 (range, 227-12,266) in LABScreen and LIFECODES SAB assays, respectively. Overall, 21 patients experienced GF. Of them, 12 had primary graft rejection, 8 had secondary graft rejection, and 1 had primary poor graft function. The cumulative incidences of GF at 28, 100, and 365 days were 4.0% (95% CI, 2.2%-6.6%), 6.6% (95% CI, 4.2%-9.8%), and 6.9% (95% CI, 4.4%-10.2%), respectively. In the multivariable analyses, DSA-positive patients had significantly delayed neutrophil (subdistribution hazard ratio [SHR] = 0.48; 95% CI, 0.29-0.81; P = .006) and platelet recovery (SHR = 0.51; 95% CI, 0.35-0.74; P = .0003) than patients without DSAs. In addition, only DSAs were significant predictors of primary GF at 28 days (SHR = 2.78; 95% CI, 1.65-4.68; P = .0001). The Fine-Gray regression also demonstrated that the presence of DSAs was strongly associated with a higher incidence of overall GF (SHR = 7.60; 95%CI, 2.61-22.14; P = .0002). DSA-positive patients with GF had significantly higher median MFI values than DSA-positive patients who achieved engraftment in LIFECODES SAB assay using neat serum (10,334 vs. 1250; P = .006) and in LABScreen SAB at 1:32 dilution (1627 vs. 61; P = .006). All 3 patients with C1q-positive DSAs failed to engraft. DSAs were not predictive of inferior survival (hazard ratio = 0.50; 95% CI, 0.20-1.26, P = .14). CONCLUSIONS Our results validate the presence of DSAs as a significant risk factor for GF and poor hematologic recovery after unrelated donor allo-HCT. Thus, careful pre-transplant DSA evaluation may optimize unrelated donor selection and improve allo-HCT outcomes.
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Affiliation(s)
- Alberto Cardoso Martins Lima
- Immunogenetics Laboratory - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil; Immunogenetics Institute (IGEN), Associação Fundo de Incentivo à Pesquisa, São Paulo, SP, Brazil.
| | - Joselito Getz
- Immunogenetics Laboratory - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
| | - Geovana Borsato do Amaral
- Immunogenetics Laboratory - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
| | - Gisele Loth
- Bone Marrow Transplantation Unit - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil; Instituto de Pesquisa Pelé Pequeno Príncipe, Hospital Pequeno Príncipe, Curitiba, PR, Brazil
| | - Vaneuza Araújo Moreira Funke
- Bone Marrow Transplantation Unit - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
| | - Samir Kanaan Nabhan
- Bone Marrow Transplantation Unit - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
| | | | - Renato de Marco
- Immunogenetics Institute (IGEN), Associação Fundo de Incentivo à Pesquisa, São Paulo, SP, Brazil
| | - Maria Gerbase-DeLima
- Immunogenetics Institute (IGEN), Associação Fundo de Incentivo à Pesquisa, São Paulo, SP, Brazil
| | - Noemi Farah Pereira
- Immunogenetics Laboratory - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
| | - Carmem Bonfim
- Bone Marrow Transplantation Unit - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil; Instituto de Pesquisa Pelé Pequeno Príncipe, Hospital Pequeno Príncipe, Curitiba, PR, Brazil
| | - Ricardo Pasquini
- Bone Marrow Transplantation Unit - Complexo Hospital de Clínicas, Federal University of Paraná, Curitiba, PR, Brazil
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