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Garcia J, Vianna R. B-Cell Induction Therapies in Intestinal Transplantation. Gastroenterol Clin North Am 2024; 53:343-357. [PMID: 39067999 DOI: 10.1016/j.gtc.2024.01.001] [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] [Indexed: 07/30/2024]
Abstract
Despite advancements in short-term outcomes since the inception of intestinal transplant, significant long-term graft failure persists. Early successes are attributed to the utilization of tacrolimus for maintenance therapy, coupled with T-cell modulating induction regimens, which effectively reduce the incidence of acute cellular rejection. However, the challenge of chronic allograft injury remains unresolved. There is increasing evidence indicating a correlation between donor-specific antibodies and the survival of visceral allografts. Strategies aimed at reducing the presence or load of these antibodies may potentially enhance long-term outcomes. Consequently, our focus is now turning toward B-cell induction therapies as a possible solution.
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Affiliation(s)
- Jennifer Garcia
- Adult and Pediatric Intestinal Transplant, Miami Transplant Institute, University of Miami-Jackson Memorial Hospital, 1801 Northwest 9th Avenue, MTI 7th Floor, Jackson Professional Building, Miami, FL 33136, USA.
| | - Rodrigo Vianna
- Adult and Pediatric Intestinal Transplant, Miami Transplant Institute, University of Miami-Jackson Memorial Hospital, 1801 Northwest 9th Avenue, MTI 7th Floor, Jackson Professional Building, Miami, FL 33136, USA
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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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Ciftci HS, Oguz FS, Cinar CK, Izgi DK. The correlation of results of panel reactive antibody, identification, and single antigen beads in detection of anti-HLA antibodies: Istanbul Faculty of Medicine, tissue typing laboratory experience. Transpl Immunol 2023; 80:101891. [PMID: 37433395 DOI: 10.1016/j.trim.2023.101891] [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: 04/12/2023] [Revised: 06/23/2023] [Accepted: 07/01/2023] [Indexed: 07/13/2023]
Abstract
BACKGROUND We have performed a retrospective analysis of anti-HLA class I MHC and class II MHC antibodies measured using a single antigen bead (SAB) assay and a panel reactive antibody (PRA) assay. MATERIAL AND METHODS A group of 256 patients with end-stage renal disease (ESRD) was tested for anti-HLA antibodies in the tissue typing laboratory between 2017 and 2020. In the cohort, the serum samples of patients waiting for transplantation were tested. Both the PRA and SAB tests of these patients were analyzed using the Luminex (Immucor) method. The threshold of positivity was accepted as median fluorescence intensities (MFI) ≥1000 for PRA screening and MFI ≥750 for SAB screening. RESULTS Overall, antibodies to HLA antigens were detected in 202 (78.9%) out of 256 patients in the PRA study. Antibodies against both class I/II antigens were detected only in 15.6% of these patients, whereas antibodies against only against class I HLA in 31.3% and only against class II HLA in 32.0%. By comparison, the SAB study found that 66.8% of patients were positive for HLA antigens. Furthermore, donor-specific antibodies (DSA) were detected in 52.0% of PRA-positive patients and 52.6% of SAB-positive patients. It was shown that 168 patients (83.2%) out of 202 PRA-positive patients were found to be SAB-positive. In addition, 51 patients negative in the SAB assay (94.4%) were also negative in the PRA assay. Statistical analysis established a significant correlation between the PRA and SAB positivity (p > 0.001). It was also shown that MFI ≥3000 PRA positivity for class I HLA antigens (p = 0.049) and MFI ≥5000 PRA positivity for class II antigens (p < 0.001) correlated with the SAB positivity in patients. CONCLUSION Our results showed the importance of both PRA and SAB assays to define the status of sensitization in patients.
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Affiliation(s)
- Hayriye Senturk Ciftci
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Biology, Tissue Typing Laboratory, Istanbul-Turkiye, Millet street Fatih, Istanbul 34093, Turkey.
| | - Fatma Savran Oguz
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Biology, Tissue Typing Laboratory, Istanbul-Turkiye, Millet street Fatih, Istanbul 34093, Turkey
| | - Cigdem Kekik Cinar
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Biology, Tissue Typing Laboratory, Istanbul-Turkiye, Millet street Fatih, Istanbul 34093, Turkey.
| | - Demet Kivanc Izgi
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Biology, Tissue Typing Laboratory, Istanbul-Turkiye, Millet street Fatih, Istanbul 34093, Turkey; Istanbul University, Institute of Health Sciences/Medical Biology, Istanbul, Turkiye
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Seeking Standardized Definitions for HLA-incompatible Kidney Transplants: A Systematic Review. Transplantation 2023; 107:231-253. [PMID: 35915547 DOI: 10.1097/tp.0000000000004262] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND There is no standard definition for "HLA incompatible" transplants. For the first time, we systematically assessed how HLA incompatibility was defined in contemporary peer-reviewed publications and its prognostic implication to transplant outcomes. METHODS We combined 2 independent searches of MEDLINE, EMBASE, and the Cochrane Library from 2015 to 2019. Content-expert reviewers screened for original research on outcomes of HLA-incompatible transplants (defined as allele or molecular mismatch and solid-phase or cell-based assays). We ascertained the completeness of reporting on a predefined set of variables assessing HLA incompatibility, therapies, and outcomes. Given significant heterogeneity, we conducted narrative synthesis and assessed risk of bias in studies examining the association between death-censored graft failure and HLA incompatibility. RESULTS Of 6656 screened articles, 163 evaluated transplant outcomes by HLA incompatibility. Most articles reported on cytotoxic/flow T-cell crossmatches (n = 98). Molecular genotypes were reported for selected loci at the allele-group level. Sixteen articles reported on epitope compatibility. Pretransplant donor-specific HLA antibodies were often considered (n = 143); yet there was heterogeneity in sample handling, assay procedure, and incomplete reporting on donor-specific HLA antibodies assignment. Induction (n = 129) and maintenance immunosuppression (n = 140) were frequently mentioned but less so rejection treatment (n = 72) and desensitization (n = 70). Studies assessing death-censored graft failure risk by HLA incompatibility were vulnerable to bias in the participant, predictor, and analysis domains. CONCLUSIONS Optimization of transplant outcomes and personalized care depends on accurate HLA compatibility assessment. Reporting on a standard set of variables will help assess generalizability of research, allow knowledge synthesis, and facilitate international collaboration in clinical trials.
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Olszowska-Zaremba N, Gozdowska J, Zagożdżon R. Clinical significance of low pre-transplant donor specific antibodies (DSA) in living donor kidney recipients with negative complement-dependent cytotoxicity crossmatches (CDCXM), and negative flow cytometry crossmatches (FLXM) - A single-center experience. Transpl Immunol 2022; 74:101672. [PMID: 35868613 DOI: 10.1016/j.trim.2022.101672] [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: 04/26/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND It is controversial whether all donor-specific antibodies (DSA) detected by the solid-phase single antigen bead (SAB) assay negatively affect kidney transplantation outcomes. The study aimed to evaluate the possible clinical significance of low pre-transplant DSA in living donor kidney recipients. We analyzed a group of patients with HLA-A, B, and -DR DSA reactivities below a virtual crossmatch (VXM) value of 5000 MFI but with all VXM DSA reactivities at HLA-DQ, -DP, and -Cw, which were not typed routinely for donors prior to transplantation. We also investigated the incidence of persistent and de novo DSAs in available posttransplant SAB assays. METHODS From the historical cohort of living donor recipients transplanted between 2014 and 2018 at our center (n = 82), 55 patients met the inclusion criteria, namely: these patients were > 18 years old with non-HLA identical sibling donors, who were not desensitized, who had available pre-transplant SAB results, and who had negative both complement-dependent cytotoxicity crossmatch (CDCXM) and flow cytometry crossmatch (FLXM) results. An additional donor HLA typing, performed for all 55 recipients, identified donor additional HLA-DQ, -DP, and -Cw DSA reactivities. These patients were then divided by SAB reactivity into three groups: 1) those with DSA-positive reactivities; 2) those with non-donor-specific anti-HLA reactivities (NDSA); and, 3) those who were anti-HLA-negative. All these recipients were followed for three years and checked for their de novo or persistent DSA. RESULTS In the studied cohort, DSA-positive, NDSA reactive, and anti-HLA negative recipients constituted 33%, 36%, and 31% of 55 patients, respectively. Non-routinely considered pre-transplant HLA-DQ, -DP, and -Cw DSA-positive reactivities were shown in as many as 78% of DSA-positive cases (group 1) with the lowest MFI value of 319 to DP4 and the highest MFI of 5767 to DQ2. Of the pre-transplant HLA-A, B, and -DR DSA reactivities, only -DR52 DSA reactivity reached the highest MFI value of 2191. These detected DSAs did not reduce the mean estimated glomerular filtration rate (eGFR) values and did not increase the incidence of proteinuria in recipients. While the 3-year graft survival was lower in the DSA-positive group (94.4%) with one recipient who lost kidney transplant, the difference was not significantly different (p = 0.7) from the NDSA (100%) and negative (100%) groups. In terms of the incidence of de novo acute antibody-mediated rejection (AMR) at three years after transplantation, no case has been reported in the cohort. This may suggest that low DSA-positive recipients do not experience higher rejection rate. However, DSA-positive recipients had a tendency for a higher frequency of C4d deposits in peritubular capillaries (PTC) and de novo DSA. CONCLUSION Our 3-year follow-up of patients with low pre-transplant DSA found no association with a deterioration in graft function and worse graft survival. Furthermore, we did not observe an increase in AMR in our patients with low DSA. A larger cohort and a longer follow-up period may be needed to evaluate the tendency of low DSA-positive recipients towards the higher incidence of C4d deposits in PTC and/or de novo DSA.
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Affiliation(s)
- Natasza Olszowska-Zaremba
- Department of Clinical Immunology, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland.
| | - Jolanta Gozdowska
- Department of Transplantation Medicine, Nephrology and Internal Medicine, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland.
| | - Radosław Zagożdżon
- Department of Clinical Immunology, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland; Department of Immunology, Transplantology and Internal Medicine, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland.
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Aspectos técnicos y clínicos de la prueba cruzada de histocompatibilidad en el trasplante de órganos sólidos. BIOMÉDICA 2022; 42:391-413. [PMID: 35867930 PMCID: PMC9467682 DOI: 10.7705/biomedica.6255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Indexed: 11/21/2022]
Abstract
La presencia de anticuerpos dirigidos contra los antígenos leucocitarios humanos (Human Leukocyte Antigens, HLA) que se expresan en las células del donante, es uno de los factores de riesgo más importantes asociados con las complicaciones clínicas después del trasplante. La prueba cruzada es una de las pruebas de histocompatibilidad más eficaces para la detección de anticuerpos específicos contra el donante en los receptores de injertos. En los primeros métodos de la prueba cruzada, se utilizaba la citotoxicidad dependiente del complemento, que es útil para detectar dichos anticuerpos responsables del rechazo hiperagudo del injerto, pero carece de la sensibilidad adecuada. Por ello, se desarrollaron métodos de pruebas cruzadas más sensibles, entre ellas, la prueba cruzada por citometría de flujo que hoy se considera el método preferido. En este artículo se revisa la evolución de la prueba cruzada y los factores más importantes que deben tenerse en cuenta al realizarla y al interpretar los resultados de esta prueba fundamental para la supervivencia a largo plazo del injerto.
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Olszowska-Zaremba N, Zagożdżon R, Gozdowska J. Accuracy of virtual crossmatch (VXM) prediction of physical crossmatch (PXM) results of donor specific antibody (DSA) in routine pretransplant settings–A single-center experience. Transpl Immunol 2022; 72:101583. [DOI: 10.1016/j.trim.2022.101583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 03/15/2022] [Accepted: 03/15/2022] [Indexed: 11/26/2022]
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Sullivan HC, Krummey SM, Gebel HM, Bray RA. The utility of second single antigen bead assay: Clearing the water or stirring up mud? Hum Immunol 2020; 81:663-670. [PMID: 33036787 PMCID: PMC8336427 DOI: 10.1016/j.humimm.2020.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/25/2020] [Accepted: 09/24/2020] [Indexed: 12/01/2022]
Abstract
Though solid-phase single antigen bead (SAB) testing has provided major advances to the HLA community and organ allocation, it has not been without limitations. In particular, false-positive reactions lead to interpretative challenges and the potential to preclude a transplant if the corresponding antigens are deemed unacceptable. Two different vendor platforms are commercially available for SAB testing, one more recent than the other. The aim herein was to assess the benefit of using the newer SAB platform in situations where the primary platform yielded suspicious (specifically, false positive) reactions. Therefore, 42 serum samples with commonly encountered false-positive patterns observed in our laboratory were tested with the newer platform. Cases were classified as resolved, equivalent, or divergent based on whether the second platform produced no reactivity, the same pattern, or a distinctly different pattern compared to the primary platform, respectively. Approximately 33% of cases were resolved, 46% were equivalent, and 21% were divergent. The project revealed advantages of adding a second SAB platform to the laboratory's test menu including resolving challenging samples and including broader coverage of different alleles and unique class II alpha/beta subunit combinations. However, the challenges of validating, maintaining, and billing for another test method in the laboratory may be barriers to routine use.
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Affiliation(s)
- Harold C Sullivan
- Emory University, Department of Pathology and Laboratory Medicine, Atlanta, GA, USA.
| | - Scott M Krummey
- Emory University, Department of Pathology and Laboratory Medicine, Atlanta, GA, USA
| | - Howard M Gebel
- Emory University, Department of Pathology and Laboratory Medicine, Atlanta, GA, USA
| | - Robert A Bray
- Emory University, Department of Pathology and Laboratory Medicine, Atlanta, GA, USA
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Thammanichanond D, Sukhumvat S, Tammakorn C, Siriyotha S, Kantachuvesiri S. Comparison Between Phenotypic Bead Assay and Single Antigen Bead Assay for Determining Specificity of HLA Antibodies in Kidney Transplant Waiting List. Transplant Proc 2020; 52:1675-1679. [PMID: 32448666 DOI: 10.1016/j.transproceed.2020.01.153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 01/22/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The determination of unacceptable antigens in patients on kidney transplant waiting list is a critical laboratory investigation in sensitized patients. The Luminex single antigen bead (SAB) assay has high sensitivity and accuracy. However, several countries have not yet implemented SAB testing for waitlisted patients because of limited financial resources. In Thailand, specificities of HLA antibodies are identified by using a phenotypic bead assay. The aim of this study was to evaluate the performance of the phenotypic bead assay for determining HLA antibody specificities when compared with the SAB assay. METHODS A total of 254 sera from patients awaiting kidney transplantation were included. Of 254 sera, 206 and 171 were positive for HLA class I and II antibodies, respectively. Antibody specificities of sera that were tested with both phenotypic and SAB assay were analyzed. The performances of the phenotypic bead assay were compared with those of the SAB assay as the gold standard by using estimation of pooling sensitivity, specificity, and accuracy. RESULTS The sensitivity, specificity, and accuracy of the phenotypic bead assay for determining HLA class I antibodies was 53.9%, 93.0%, and 78.1%, respectively. The sensitivity, specificity, and accuracy of the phenotypic bead assay for determining HLA class II antibodies were 57.3%, 94.9%, and 81.4% respectively. CONCLUSION In waitlisted kidney transplant patients, the phenotypic bead assay had high specificity and moderate accuracy when compared with the SAB assay. However, the low sensitivity of the test suggests that the use of the phenotypic assay for determining HLA specificities should be applied with caution in sensitized patients.
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Affiliation(s)
- Duangtawan Thammanichanond
- Histocompatibility and Immunogenetics Laboratory, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | - Sireewan Sukhumvat
- Histocompatibility and Immunogenetics Laboratory, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Chutima Tammakorn
- Histocompatibility and Immunogenetics Laboratory, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Sukanya Siriyotha
- Section for Clinical Epidemiology and Biostatistics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Surasak Kantachuvesiri
- Division of Nephrology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Choi J, Chandraker A. Immunologic Risk Assessment and Approach to Immunosuppression Regimen in Kidney Transplantation. Clin Lab Med 2019; 39:643-656. [PMID: 31668275 DOI: 10.1016/j.cll.2019.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The outcomes of kidney transplantation show a steady improvement with an increasing number of transplantations and decreasing incidence of acute rejection episodes. Successful transplantation begins with a comprehensive immunologic risk assessment and judicious choice of therapeutic agents. In this review, we discuss the trends in transplant immunosuppression practices and outcomes in the United States. We discuss practical testing algorithms for clinical decision making in induction therapy and fine-tuning maintenance immunosuppression. We introduce assessment tools for immune monitoring after transplantation and speculate on future directions in management.
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Affiliation(s)
- John Choi
- Transplantation Research Center, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Anil Chandraker
- Transplantation Research Center, Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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DSA-FXM: Accelerated Donor-specific Flow Crossmatch Discriminating Class I and II Antibody Specifically and Only to Donor HLA for Determining True Incompatibility. Transplantation 2019; 104:813-822. [PMID: 31385929 DOI: 10.1097/tp.0000000000002900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Worldwide, a final crossmatch is the gold standard for determining compatibility between patient and donor before solid organ transplantation and preventing hyperacute rejection. In the absence of autoantibodies, an incompatible crossmatch in a sensitized patient is attributed to mismatched donor HLA. However, current physical crossmatch methods cannot distinguish reactivity to HLA from other clinically irrelevant cell surface targets nor the class of HLA if it is the target. Result interpretation is difficult or impossible when autoantibodies, alloantibodies, or therapeutic antibodies coexist. METHODS Herein, we describe a unique donor-specific flow crossmatch (DSA-FXM) that distinguishes HLA class I or II donor-specific antibody bound to HLA antigens on the donor cell surface in their native conformation that is not impacted by rituximab, anti-thymocyte globulin (after absorption), or autoantibodies. It is HLA specific. RESULTS We compared the results of single-antigen antibody testing, autoreactive and alloreactive flow cytometry crossmatches (FXM) using traditional FXM and our DSA-FXM method from 94 patients (enriched for auto+/allo+ pairs; n = 64) against 110 donors (338 tests) and show that, in our cohort, positive traditional FXM results are not directed to donor HLA 60.25% of the time and negative traditional FXM results are missing HLA donor-specific antibody 36.2% of the time based on the DSA-FXM. CONCLUSIONS We demonstrate that the DSA-FXM is able to define categorically distinct and clinically important HLA antibody profiles in half the time required for the standard FXM, potentially shortening cold ischemia time and providing clinicians with unambiguous essential information regarding HLA compatibility when time is critical.
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Navas A, Molina J, Agüera ML, Guler I, Jurado A, Rodríguez-Benot A, Alonso C, Solana R. Characterization of the C1q-Binding Ability and the IgG1-4 Subclass Profile of Preformed Anti-HLA Antibodies by Solid-Phase Assays. Front Immunol 2019; 10:1712. [PMID: 31428086 PMCID: PMC6687874 DOI: 10.3389/fimmu.2019.01712] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 07/08/2019] [Indexed: 12/11/2022] Open
Abstract
Humoral alloimmunity, particularly that triggered by preformed antibodies against human leukocyte antigens (HLA), is associated with an increased prevalence of rejection and reduced transplant survival. The high sensitivity of solid phase assays, based on microbeads coated with single antigens (SAB), consolidated them as the gold-standard method to characterize anti-HLA antibodies, ensuring a successful allograft allocation. Mean fluorescence intensity (MFI) provided by SAB is regularly used to stratify the immunological risk, assuming it as a reliable estimation of the antibody-level, but it is often limited by artifacts. Beyond MFI, other properties, such as the complement-binding ability or the IgG1-4 subclass profile have been examined to more accurately define the clinical relevance of antibodies and clarify their functional properties. However, there are still unresolved issues. Neat serum-samples from 20 highly-sensitized patients were analyzed by SAB-panIgG, SAB-IgG1-4 subclass and SAB-C1q assays. All 1:16 diluted serum-samples were additionally analyzed by SAB-panIgG and SAB-IgG1-4 subclass assays. A total of 1,285 anti-HLA antibodies were identified as positive, 473 (36.8%) of which were C1q-binding. As expected, serum-dilution enhanced the correlation between the C1q-binding ability and the antibody-strength, measured as the MFI (rneat = 0.248 vs. rdiluted = 0.817). SAB-subclass assay revealed at least one IgG1-4 subclass in 1,012 (78.8%) positive antibody-specificities. Among them, strong complement-binding subclasses, mainly IgG1, were particularly frequent (98.9%) and no differences were found between C1q- and non-C1q-binding antibodies regarding their presence (99.4 vs. 98.5%; p = 0.193). In contrast, weak or non-C1q-binding subclasses (IgG2/IgG4) were more commonly detected in C1q-binding antibodies (78.9 vs. 38.6%; p < 0.001). Interestingly, a strong association was found between the C1q-binding ability and the IgG1 strength (rIgG1dil = 0.796). Though lower, the correlation between the IgG2 strength and the C1q-binding ability was also strong (rIgG2dil = 0.758), being both subclasses closely related (rIgG1−IgG2 = 0.817). We did not find any correlation with the C1q-binding ability considering the remaining subclasses. In conclusion, we demonstrate that a particular profile of IgG subclasses (IgG1/IgG3) itself does not determine at all the ability to bind complement of anti-HLA antibodies assessed by SAB-C1q assay. It is the IgG subclass strength, mainly of IgG1, which usually appears in combination with IgG2, that best correlates with it.
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Affiliation(s)
- Ana Navas
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Immunology and Allergy, Reina Sofia University Hospital, Cordoba, Spain
| | - Juan Molina
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Immunology and Allergy, Reina Sofia University Hospital, Cordoba, Spain
| | - María-Luisa Agüera
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Nephrology, Reina Sofia University Hospital, Cordoba, Spain
| | - Ipek Guler
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
| | - Aurora Jurado
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Immunology and Allergy, Reina Sofia University Hospital, Cordoba, Spain
| | - Alberto Rodríguez-Benot
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Nephrology, Reina Sofia University Hospital, Cordoba, Spain
| | - Corona Alonso
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Immunology and Allergy, Reina Sofia University Hospital, Cordoba, Spain
| | - Rafael Solana
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.,Department of Immunology and Allergy, Reina Sofia University Hospital, Cordoba, Spain
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Greenshields AL, Liwski RS. The ABCs (DRDQDPs) of the prozone effect in single antigen bead HLA antibody testing: Lessons from our highly sensitized patients. Hum Immunol 2019; 80:478-486. [DOI: 10.1016/j.humimm.2019.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/19/2019] [Accepted: 04/26/2019] [Indexed: 11/15/2022]
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14
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Greenshields A, Bray RA, Gebel HM, Liwski RS. Getting on target: Development of the novel, prozone-resistant, dual antibody rapid test (DART) for the LABScreen single antigen bead (SAB) assay. Hum Immunol 2019; 80:468-477. [DOI: 10.1016/j.humimm.2019.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/20/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022]
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15
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Donor-specific antibody management in intestine transplantation: hope for improving the long-term durability of the intestine allograft? Curr Opin Organ Transplant 2019; 24:212-218. [DOI: 10.1097/mot.0000000000000619] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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16
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Wehmeier C, Hönger G, Cun H, Amico P, Hirt-Minkowski P, Georgalis A, Hopfer H, Dickenmann M, Steiger J, Schaub S. Donor Specificity but Not Broadness of Sensitization Is Associated With Antibody-Mediated Rejection and Graft Loss in Renal Allograft Recipients. Am J Transplant 2017; 17:2092-2102. [PMID: 28245084 DOI: 10.1111/ajt.14247] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/13/2017] [Accepted: 02/17/2017] [Indexed: 01/25/2023]
Abstract
Panel-reactive antibodies are widely regarded as an important immunological risk factor for rejection and graft loss. The broadness of sensitization against HLA is most appropriately measured by the "calculated population-reactive antibodies" (cPRA) value. In this study, we investigated whether cPRA represent an immunological risk in times of sensitive and accurate determination of pretransplantation donor-specific HLA antibodies (DSA). Five hundred twenty-seven consecutive transplantations were divided into four groups: cPRA 0% (n = 250), cPRA 1-50% (n = 129), cPRA 51-100% (n = 43), and DSA (n = 105). Patients without DSA were considered as normal risk and received standard immunosuppression without T cell-depleting induction. Patients with DSA received an enhanced induction therapy and maintenance immunosuppression. Surveillance biopsies were performed at 3 and 6 months. Median follow-up was 5.7 years. Among the three cPRA groups, there were no differences regarding the 1-year incidence of ABMR (p = 0.16) and TCMR (p = 0.75). The 5-year allograft survival rates were similar and around 87% (p = 0.28). The estimated glomerular filtration rate at last follow-up was 50-53 mL/min (p = 0.45). On multivariable Cox proportional hazard analysis, the strongest independent predictor for ABMR and (death-censored) graft survival was pretransplantation DSA. cPRA were not predictive for ABMR, TCMR, or (death-censored) graft survival. We conclude that with current DSA assignment, the broadness of sensitization measured by cPRA does not imply an immunological risk.
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Affiliation(s)
- C Wehmeier
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - G Hönger
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.,HLA-Diagnostic and Immunogenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland.,Transplantation Immunology and Nephrology, Department of Biomedicine, University Basel, Basel, Switzerland
| | - H Cun
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - P Amico
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.,HLA-Diagnostic and Immunogenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland
| | - P Hirt-Minkowski
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - A Georgalis
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - H Hopfer
- Institute for Pathology, University Hospital Basel, Basel, Switzerland
| | - M Dickenmann
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - J Steiger
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
| | - S Schaub
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.,HLA-Diagnostic and Immunogenetics, Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland.,Transplantation Immunology and Nephrology, Department of Biomedicine, University Basel, Basel, Switzerland
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Virtual HLA Crossmatching as a Means to Safely Expedite Transplantation of Imported Pancreata. Transplantation 2017; 100:1103-10. [PMID: 26950720 DOI: 10.1097/tp.0000000000001125] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Imported pancreata accumulate cold ischemia time (CIT), limiting utilization and worsening outcomes. Flow cytometric crossmatching (FXM) is a standard method to assess recipient and donor compatibility, but can prolong CIT. Single-antigen bead assays allow for detection of recipient donor-specific HLA antibodies, enabling prediction of compatibility through a "virtual crossmatch" (VXM). This study investigates the utility and outcomes of VXM after transplantation of imported pancreata. METHODS We retrospectively compared outcomes of 153 patients undergoing pancreas transplantation at our institution over a 3.5-year period. RESULTS Three patient groups were analyzed based on geographic source of the pancreas graft and the type of prospective crossmatch performed: (1) imported VXM-only, n = 39; (2) imported VXM + FXM, n = 12; and (3) local VXM + FXM, n = 102. There were no episodes of hyperacute rejection and 1 episode of early antibody-mediated rejection (<90 days) in the imported VXM group. Death-censored graft survival, patient survival, and rejection rates were comparable among the recipient groups. For pancreata imported from United Network of Organ Sharing regions 3 and 4, proceeding to surgery without an FXM reduced CIT by 5.1 hours (P < 0.001). The time from organ arrival at the hospital to operation start was significantly shorter in the VXM-only group compared with the VXM + FXM group (P < 0.001). CONCLUSIONS Virtual crossmatch helps minimize CIT without increasing rejection or adversely affecting graft survival, making it a viable method to increase pancreas graft utilization across distant organ sharing regions.
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Juhl D, Marget M, Hallensleben M, Görg S, Ziemann M. Assignment of C1q-binding HLA antibodies as unacceptable HLA antigens avoids positive CDC-crossmatches prior to transplantation of deceased donor organs. Transpl Immunol 2017; 41:17-21. [DOI: 10.1016/j.trim.2017.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/30/2016] [Accepted: 01/06/2017] [Indexed: 10/20/2022]
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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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20
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Rohan VS, Taber DJ, Moussa O, Pilch NA, Denmark S, Meadows HB, McGillicuddy JW, Chavin KD, Baliga PK, Bratton CF. Transplanting Sensitized Kidney Transplant Patients With Equivalent Outcomes Utilizing Stringent HLA Crossmatching. EXP CLIN TRANSPLANT 2016; 15:47-55. [PMID: 27267614 DOI: 10.6002/ect.2015.0274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECIVES Elevated panel reactive antibody levels have been traditionally associated with increased acute rejection rate and decreased long-term graft survival after kidney transplant. In this study, our objective was to determine patient and allograft outcomes in sensitized kidney transplant recipients with advanced HLA antibody detection and stringent protein sequence epitope analyses. MATERIALS AND METHODS This was a subanalysis of a prospective, risk-stratified randomized controlled trial that compared interleukin 2 receptor antagonist to rabbit antithymocyte globulin induction in 200 kidney transplant recipients, examining outcomes based on panel reactive antibody levels of < 20% (low) versus ≥ 20% (high, sensitized). The study was conducted between February 2009 and July 2011. All patients underwent solid-phase single antigen bead assays to detect HLA antibodies and stringent HLA epitope analyses with protein sequence alignment for virtual crossmatching. Delayed graft function, acute rejection rates, and graft loss were the main outcomes measured. RESULTS Both the low (134 patients) and high (66 patients) panel reactive antibody level cohorts had equivalent induction and maintenance immunosuppression. Patients in the high-level group were more likely to be female (P < .001), African American (P < .001), and received a kidney from a deceased donor (P = .004). Acute rejection rates were similar between the low (rate of 8%) and high (rate of 9%) panel reactive antibody groups (P = .783). Delayed graft function, borderline rejection, graft loss, and death were not different between groups. Multivariate analyses demonstrated delayed graft function to be the strongest predictor of acute rejection (odds ratio, 5.7; P = .005); panel reactive antibody level, as a continuous variable, had no significant correlation with acute rejection (C statistic, 0.48; P = .771). CONCLUSIONS Appropriate biologic matching with single antigen bead assays and stringent epitope analyses provided excellent outcomes in sensitized patients regardless of the induction therapy choice.
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Affiliation(s)
- Vinayak S Rohan
- From the Division of Transplant Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
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21
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Baxter-Lowe LA, Kucheryavaya A, Tyan D, Reinsmoen N. CPRA for allocation of kidneys in the US: More candidates ≥98% CPRA, lower positive crossmatch rates and improved transplant rates for sensitized patients. Hum Immunol 2016; 77:395-402. [PMID: 27012168 DOI: 10.1016/j.humimm.2016.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 02/06/2023]
Abstract
In 2009 calculated panel reactive antibody (CPRA) replaced PRA as the metric for HLA sensitization in the US kidney allocation system. During the next four years, registrants with at least one unacceptable antigen increased (34-40%) and registrants with ≥98% PRA/CPRA increased from 7% to 9% of the waitlist. These changes were accompanied by a reduction in kidney offers refused for positive crossmatch: 14,137 (1.7%) in 2009 and 3,310 in 2013 (0.4%). Registrants with ≥98% PRA/CPRA had highest rates of refusal but also showed substantial improvement (20% in 2009 vs 8% in 2013). For registrants with ≥98% PRA/CPRA, 45% of accepted offers in 2009 were not transplanted into the intended recipient compared to 11% in 2013. Transplant rates remained low for these patients (∼50/1000 active patient-years), but rates improved for patients with 80-97% PRA/CPRA (223/1000 active patient-years in 2009 vs 354/1000 in 2013). In 2013, 40% regraft candidates had CPRA ≥98% compared to 4% of primary graft candidates. More females than males were ≥98% CPRA (14% vs 7%) and more females had CPRA above 0 (50% vs 28%). In the CPRA era, listing of unacceptable antigens increased, positive crossmatches were diminished and transplant rates for sensitized patients improved.
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Affiliation(s)
- Lee Ann Baxter-Lowe
- Children's Hospital Los Angeles and University of Southern California, Los Angeles, CA, United States.
| | | | - Dolly Tyan
- Stanford University, Palo Alto, CA, United States
| | - Nancy Reinsmoen
- Cedars-Sinai and University of California Los Angeles, Los Angeles, CA, United States
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22
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Alheim M, Paul PK, Hauzenberger DM, Wikström AC. Improved flow cytometry based cytotoxicity and binding assay for clinical antibody HLA crossmatching. Hum Immunol 2015; 76:849-57. [PMID: 26429307 DOI: 10.1016/j.humimm.2015.09.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 09/02/2014] [Accepted: 09/28/2015] [Indexed: 11/29/2022]
Abstract
The presence of preformed donor-specific HLA antibodies leads to early antibody mediated kidney allograft rejection. Therefore, detection and avoidance of donor reactive HLA antibodies prior to transplantation is of outmost importance in order to minimize the risk of rejection. Detection of pre-formed HLA antibodies is currently performed using complement-dependent cytotoxicity (CDC) assay alone or together with a flow cytometry based crossmatch (FCXM). This study was initiated to further evaluate our recently developed flow cytometry based procedure for determination of both cytotoxicity of and IgG binding to donor-derived lymphocytes by HLA antibodies. Highly enriched immuno-magnetic bead purified T and B lymphocytes were used as target cells for patient sera using 96-well plates. Importantly, the assay shows high sensitivity and specificity as determined by HLA typed donor cells and serum with defined HLA antibody IgG and C1q. Based on this and additional data generated in this paper, such as evaluation of appropriate serum and complements incubation times and assay reproducibility and stability, will enable us to more rapidly implement this assay in our clinical laboratory routines. In addition, we demonstrate that FCtox crossmatching of deceased donor cells has superior specificity compared to conventional CDC assay especially regarding high frequencies of false-positive reactions.
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Affiliation(s)
- Mats Alheim
- Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
| | - Prashanta Kumer Paul
- Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Dan-Mikael Hauzenberger
- Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ann-Charlotte Wikström
- Department of Laboratory Medicine, Division of Clinical Immunology and Transfusion Medicine, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, NOVUM, SE-141 57 Stockholm, Sweden
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Cruzado JM, Manonelles A, Vila H, Melilli E, Sala N, Bestard O, Torras J, Tebé C, Riera L, Grinyó JM. Residual urinary volume is a risk factor for primary nonfunction in kidney transplantation. Transpl Int 2015; 28:1276-82. [DOI: 10.1111/tri.12625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 02/26/2015] [Accepted: 06/15/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Josep M. Cruzado
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Anna Manonelles
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Helena Vila
- Urology Department; Hospital Universitari de Bellvitge; L'Hospitalet de Llobregat Spain
| | - Edoardo Melilli
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Neus Sala
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Oriol Bestard
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Joan Torras
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
| | - Cristian Tebé
- Statistical Advisory Service; Bellvitge Biomedical Institute-IDIBELL; Faculty of Medicine and Health Sciences; University Rovira i Virgili; L'Hospitalet de Llobregat Spain
| | - Lluís Riera
- Urology Department; Hospital Universitari de Bellvitge; L'Hospitalet de Llobregat Spain
| | - Josep M. Grinyó
- Nephrology Department; Hospital Universitari de Bellvitge; University of Barcelona; IDIBELL; L'Hospitalet de Llobregat Spain
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24
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Böhmig GA, Kikic Z, Wahrmann M, Eskandary F, Aliabadi AZ, Zlabinger GJ, Regele H, Feucht HE. Detection of alloantibody-mediated complement activation: A diagnostic advance in monitoring kidney transplant rejection? Clin Biochem 2015; 49:394-403. [PMID: 26118475 DOI: 10.1016/j.clinbiochem.2015.05.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/23/2015] [Accepted: 05/28/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Antibody-mediated rejection (ABMR) is an important cause of kidney allograft injury. In the last two decades, detection of complement split product C4d along transplant capillaries, a footprint of antibody-mediated classical complement activation, has evolved as a useful diagnostic marker of ABMR. While it was recognized that ABMR may occur also in the absence of C4d, numerous studies have shown that C4d deposition may indicate a more severe rejection phenotype associated with poor graft survival. Such studies suggest a possible diagnostic benefit of ex vivo monitoring the complement-activating capability of circulating alloantibodies. DESIGN AND METHODS We reviewed the literature between 1993 and 2015, focusing on in vivo (biopsy work-up) and in vitro detection (modified bead array technology) of HLA antibody-triggered classical complement activation in kidney transplantation. RESULTS Precise HLA antibody detection methods, in particular Luminex-based single antigen bead (SAB) assays, have provided a valuable basis for the design of techniques for in vitro detection of HLA antibody-triggered complement activation reflected by C1q, C4 or C3 split product deposition to the bead surface. Establishing such assays it was recognized that deposition of complement products to SAB, which critically depends on antibody binding strength, may be a cardinal trigger of the prozone effect, a troublesome in vitro artifact caused by a steric interference with IgG detection reagents. False-low IgG results, especially on SAB with extensive antibody binding, have to be considered when interpreting studies analyzing the diagnostic value of complement in relation to standard IgG detection. Levels of complement-fixing donor-specific antibodies (DSA) were shown to correlate with the results of standard crossmatch tests, suggesting potential application for crossmatch prediction. Moreover, while the utility of pre-transplant complement detection, at least in crossmatch-negative transplant recipients, is controversially discussed, a series of studies have shown that the appearance of post-transplant complement-fixing DSA may be associated with C4d deposition in transplant capillaries and a particular risk of graft failure. CONCLUSIONS The independent value of modified single antigen bead assays, as compared to a careful analysis of standard IgG detection, which may be affected considerably by complement dependent artifacts, needs to be clarified. Whether they have the potential to improve the predictive accuracy of our current diagnostic repertoire warrants further study.
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Affiliation(s)
- Georg A Böhmig
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
| | - Zeljko Kikic
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Markus Wahrmann
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Farsad Eskandary
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Arezu Z Aliabadi
- Department of Cardiac Surgery, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Gerhard J Zlabinger
- Institute of Immunology, Medical University Vienna, Lazarettgasse 19, A-1090 Vienna, Austria
| | - Heinz Regele
- Clinical Institute of Pathology, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria
| | - Helmut E Feucht
- Department of Organ Transplantation/Nephrology, Fachklinik Bad Heilbrunn, Wörnerweg 30, 83670 Bad Heilbrunn, Germany
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Lobashevsky AL. Methodological aspects of anti-human leukocyte antigen antibody analysis in solid organ transplantation. World J Transplant 2014; 4:153-67. [PMID: 25346888 PMCID: PMC4208078 DOI: 10.5500/wjt.v4.i3.153] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/16/2014] [Accepted: 07/25/2014] [Indexed: 02/05/2023] Open
Abstract
Donor human leukocyte antigen (HLA)-specific antibodies (DSA) play an important role in solid organ transplantation. Preexisting IgG isotype DSA are considered a risk factor for antibody mediated rejection, graft failure or graft loss. The post-transplant development of DSA depends on multiple factors including immunogenicity of mismatched antigens, HLA class II typing of the recipient, cytokine gene polymorphisms, and cellular immunoregulatory mechanisms. De novo developed antibodies require special attention because not all DSA have equal clinical significance. Therefore, it is important for transplant clinicians and transplant immunologists to accurately characterize DSA. In this review, the contemporary immunological techniques for detection and characterization of anti-HLA antibodies and their pitfalls are described.
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26
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Picascia A, Grimaldi V, Casamassimi A, De Pascale MR, Schiano C, Napoli C. Human leukocyte antigens and alloimmunization in heart transplantation: an open debate. J Cardiovasc Transl Res 2014; 7:664-75. [PMID: 25190542 DOI: 10.1007/s12265-014-9587-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 08/20/2014] [Indexed: 10/24/2022]
Abstract
Considerable advances in heart transplantation outcome have been achieved through the improvement of donor-recipient selection, better organ preservation, lower rates of perioperative mortality and the use of innovative immunosuppressive protocols. Nevertheless, long-term survival is still influenced by late complications. We support the introduction of HLA matching as an additional criterion in the heart allocation. Indeed, allosensitization is an important factor affecting heart transplantation and the presence of anti-HLA antibodies causes an increased risk of antibody-mediated rejection and graft failure. On the other hand, the rate of heart-immunized patients awaiting transplantation is steadily increasing due to the limited availability of organs and an increased use of ventricular assist devices. Significant benefits may result from virtual crossmatch approach that prevents transplantation in the presence of unacceptable donor antigens. A combination of both virtual crossmatch and a tailored desensitization therapy could be a good compromise for a favorable outcome in highly sensitized patients. Here, we discuss the unresolved issue on the clinical immunology of heart transplantation.
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Affiliation(s)
- Antonietta Picascia
- U.O.C. Division of Immunohematology, Transfusion Medicine and Transplant Immunology [SIMT], Regional Reference Laboratory of Transplant Immunology [LIT], Azienda Ospedaliera Universitaria (AOU), Second University of Naples, Piazza L. Miraglia 2, 80138, Naples, Italy,
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28
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Predicting alloreactivity in transplantation. J Immunol Res 2014; 2014:159479. [PMID: 24868561 PMCID: PMC4020392 DOI: 10.1155/2014/159479] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/13/2014] [Indexed: 01/10/2023] Open
Abstract
Human leukocyte Antigen (HLA) mismatching leads to severe complications after solid-organ transplantation and hematopoietic stem-cell transplantation. The alloreactive responses underlying the posttransplantation complications include both direct recognition of allogeneic HLA by HLA-specific alloantibodies and T cells and indirect T-cell recognition. However, the immunogenicity of HLA mismatches is highly variable; some HLA mismatches lead to severe clinical B-cell- and T-cell-mediated alloreactivity, whereas others are well tolerated. Definition of the permissibility of HLA mismatches prior to transplantation allows selection of donor-recipient combinations that will have a reduced chance to develop deleterious host-versus-graft responses after solid-organ transplantation and graft-versus-host responses after hematopoietic stem-cell transplantation. Therefore, several methods have been developed to predict permissible HLA-mismatch combinations. In this review we aim to give a comprehensive overview about the current knowledge regarding HLA-directed alloreactivity and several developed in vitro and in silico tools that aim to predict direct and indirect alloreactivity.
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29
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Djamali A, Kaufman DB, Ellis TM, Zhong W, Matas A, Samaniego M. Diagnosis and management of antibody-mediated rejection: current status and novel approaches. Am J Transplant 2014; 14:255-71. [PMID: 24401076 PMCID: PMC4285166 DOI: 10.1111/ajt.12589] [Citation(s) in RCA: 270] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 11/12/2013] [Indexed: 01/25/2023]
Abstract
Advances in multimodal immunotherapy have significantly reduced acute rejection rates and substantially improved 1-year graft survival following renal transplantation. However, long-term (10-year) survival rates have stagnated over the past decade. Recent studies indicate that antibody-mediated rejection (ABMR) is among the most important barriers to improving long-term outcomes. Improved understanding of the roles of acute and chronic ABMR has evolved in recent years following major progress in the technical ability to detect and quantify recipient anti-HLA antibody production. Additionally, new knowledge of the immunobiology of B cells and plasma cells that pertains to allograft rejection and tolerance has emerged. Still, questions regarding the classification of ABMR, the precision of diagnostic approaches, and the efficacy of various strategies for managing affected patients abound. This review article provides an overview of current thinking and research surrounding the pathophysiology and diagnosis of ABMR, ABMR-related outcomes, ABMR prevention and treatment, as well as possible future directions in treatment.
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Affiliation(s)
- A Djamali
- Division of Nephrology, Department of Medicine, University of Wisconsin School of Medicine and Public HealthMadison, WI
- Division of Transplantation, Department of Surgery, University of Wisconsin School of Medicine and Public HealthMadison, WI
| | - D B Kaufman
- Division of Transplantation, Department of Surgery, University of Wisconsin School of Medicine and Public HealthMadison, WI
| | - T M Ellis
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public HealthMadison, WI
| | - W Zhong
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public HealthMadison, WI
- Pathology and Laboratory Services, William S. Middleton Memorial Veterans HospitalMadison, WI
| | - A Matas
- Division of Transplantation, Department of Surgery, University of MinnesotaMinneapolis, MN
| | - M Samaniego
- Division of Nephrology, Department of Medicine, University of MichiganAnn Arbor, MI
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Yoo PS, Bonnel A, Kamoun M, Levine MH. Clinical outcomes among renal transplant recipients with pre-transplant weakly reactive donor-specific antibodies. Clin Transplant 2013; 28:127-33. [PMID: 24345281 DOI: 10.1111/ctr.12289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2013] [Indexed: 11/27/2022]
Abstract
BACKGROUND Alloantibody can lead to antibody-mediated rejection and graft loss in renal transplantation, necessitating an assessment of cross-match compatibility. Within the past decade, more specific solid phase assays of alloantibody have been widely adopted, allowing virtual cross-matching based on unacceptable antigens, the threshold of which is determined by individual centers. METHODS We examined the clinical outcomes of 482 patients transplanted 2007-2009 in a single center, focusing on 30 patients with weakly reactive donor-specific antibody (DSA) determined prospectively prior to renal transplant. RESULTS Compared with patients without DSA, patients with weakly reactive DSA do not have increased rates of antibody-mediated rejection, cellular rejection, or graft loss despite conventional immunosuppression utilization. CONCLUSIONS Using the screening methodology and immunosuppression regimen, we have applied to the patients with weak DSA allows them to be transplanted with equivalent outcomes as those without DSA, despite the overall higher risk characteristics of the patients in the weak DSA group.
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Affiliation(s)
- Peter S Yoo
- Department of Surgery, Section of Transplantation and Immunology, Yale University School of Medicine, New Haven, CT, USA
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31
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Al-Mohaissen MA, Virani SA. Allosensitization in heart transplantation: an overview. Can J Cardiol 2013; 30:161-72. [PMID: 24373761 DOI: 10.1016/j.cjca.2013.10.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 10/01/2013] [Accepted: 10/16/2013] [Indexed: 01/29/2023] Open
Abstract
Transplant candidates might manifest circulating antibodies against human leukocyte antigens and nonhuman leukocyte antigens, a condition termed allosensitization. The presence of these antibodies decreases a given candidate's possible donor pool, thereby prolonging the time to transplantation. They are also associated with poorer posttransplant outcomes including increased morbidity and mortality. With the increasing use of ventricular assist devices as a bridge to transplantation, the prevalence of allosensitized transplant candidates has increased. This has implications for transplant programs in terms of donor-recipient matching and managing transplant-related complications, which are more common in this high risk cohort. Controversy exists as to the best approach in managing sensitized patients, before and after transplantation. Transplant centres have used various strategies to reduce antibody loads with mixed results being reported; moreover, it remains unclear as to whether attempts at desensitization translate into better posttransplant outcomes. As an alternative management approach, some centres participate in large organ sharing strategies and allocate organs based on the probability of finding a successful donor-recipient match. In this article, the immunological basis of allosensitization, its causes, implications, and therapeutic strategies to manage sensitized patients are reviewed. The literature in relation to desensitization therapies in heart transplant candidates is also reviewed.
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Affiliation(s)
- Maha A Al-Mohaissen
- Division of Cardiology Adult Heart Transplant Program, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Sean A Virani
- Division of Cardiology Adult Heart Transplant Program, St Paul's Hospital, University of British Columbia, Vancouver, Canada.
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32
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Wahrmann M, Hlavin G, Fischer G, Marinova L, Schwaiger E, Hörl WH, Zlabinger GJ, Körmöczi GF, König F, Böhmig GA. Modified solid-phase alloantibody detection for improved crossmatch prediction. Hum Immunol 2013; 74:32-40. [DOI: 10.1016/j.humimm.2012.10.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/17/2012] [Accepted: 10/03/2012] [Indexed: 11/17/2022]
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33
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Gandhi MJ, Degoey S, Falbo D, Jenkins S, Stubbs JR, Noreen H, Lorentzen DF, Lee J, Stegall M. Inter and intra laboratory concordance of HLA antibody results obtained by single antigen bead based assay. Hum Immunol 2012; 74:310-7. [PMID: 23238217 DOI: 10.1016/j.humimm.2012.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 11/16/2012] [Accepted: 12/03/2012] [Indexed: 12/24/2022]
Abstract
Single antigen bead based assays (SAB) to identify antibodies to HLA are marketed as a qualitative test, however often used as a quantitative test as the results provide mean fluorescence intensity (MFI) which is found to correlate with the strength/avidity of the antibody. We studied the between and within laboratory variability in performing the SAB from one manufacturer. Ten samples were tested at four laboratories according to the manufacturer's suggested protocol. Additionally same samples were tested on four consecutive days in one laboratory. All tests were performed using the same lot of beads and secondary antibody. Results were classified as positive at four different MFI cutoffs: 1000, 5000, 8000 and 10,000. MFI values across and within the laboratory were compared in a pair-wise fashion with Pearson's correlations. Overall concordance for Class-I was 97% between laboratories and 98% within laboratory at all cutoffs. Pair-wise Pearson correlation between laboratories was 0.989-0.99, while within laboratory it was 0.998-0.999. For Class-II, overall concordance between and within laboratory was 98%. Pair-wise Pearson correlation between laboratories was 0.991-0.997, while within laboratory it was 0.997-0.999. There is good correlation between laboratories and within laboratory using the same manufacturer, same lot and same protocol while performing SAB.
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Affiliation(s)
- Manish J Gandhi
- Division of Transfusion Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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34
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Hawksworth JS, Rosen-Bronson S, Island E, Girlanda R, Guerra JF, Valdiconza C, Kishiyama K, Christensen KD, Kozlowski S, Kaufman S, Little C, Shetty K, Laurin J, Satoskar R, Kallakury B, Fishbein TM, Matsumoto CS. Successful isolated intestinal transplantation in sensitized recipients with the use of virtual crossmatching. Am J Transplant 2012; 12 Suppl 4:S33-42. [PMID: 22947089 DOI: 10.1111/j.1600-6143.2012.04238.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We evaluated virtual crossmatching (VXM) for organ allocation and immunologic risk reduction in sensitized isolated intestinal transplantation recipients. All isolated intestine transplants performed at our institution from 2008 to 2011 were included in this study. Allograft allocation in sensitized recipients was based on the results of a VXM, in which the donor-specific antibody (DSA) was prospectively evaluated with the use of single-antigen assays. A total of 42 isolated intestine transplants (13 pediatric and 29 adult) were performed during this time period, with a median follow-up of 20 months (6-40 months). A sensitized (PRA ≥ 20%) group (n = 15) was compared to a control (PRA < 20%) group (n = 27) to evaluate the efficacy of VXM. With the use of VXM, 80% (12/15) of the sensitized patients were transplanted with a negative or weakly positive flow-cytometry crossmatch and 86.7% (13/15) with zero or only low-titer (≤ 1:16) DSA. Outcomes were comparable between sensitized and control recipients, including 1-year freedom from rejection (53.3% and 66.7% respectively, p = 0.367), 1-year patient survival (73.3% and 88.9% respectively, p = 0.197) and 1-year graft survival (66.7% and 85.2% respectively, p = 0.167). In conclusion, a VXM strategy to optimize organ allocation enables sensitized patients to successfully undergo isolated intestinal transplantation with acceptable short-term outcomes.
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Affiliation(s)
- J S Hawksworth
- Georgetown Transplant Institute, Georgetown University Hospital, Washington, DC, USA
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35
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Abu-Elmagd KM, Wu G, Costa G, Lunz J, Martin L, Koritsky DA, Murase N, Irish W, Zeevi A. Preformed and de novo donor specific antibodies in visceral transplantation: long-term outcome with special reference to the liver. Am J Transplant 2012; 12:3047-60. [PMID: 22947059 DOI: 10.1111/j.1600-6143.2012.04237.x] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite improvement in early outcome, rejection particularly chronic allograft enteropathy continues to be a major barrier to long-term visceral engraftment. The potential role of donor specific antibodies (DSA) was examined in 194 primary adult recipients. All underwent complement-dependent lymphocytotoxic crossmatch (CDC-XM) with pre- and posttransplant solid phase HLA-DSA assay in 156 (80%). Grafts were ABO-identical with random HLA-match. Liver was included in 71 (37%) allografts. Immunosuppression was tacrolimus-based with antilymphocyte recipient pretreatment in 150 (77%). CDC-XM was positive in 55 (28%). HLA-DSA was detectable before transplant in 49 (31%) recipients with 19 continuing to have circulating antibodies. Another 19 (18%) developed de novo DSA. Ninety percent of patients with preformed DSA harbored HLA Class-I whereas 74% of recipients with de novo antibodies had Class-II. Gender, age, ABO blood-type, cold ischemia, splenectomy and allograft type were significant DSA predictors. Preformed DSA significantly (p < 0.05) increased risk of acute rejection. Persistent and de novo HLA-DSA significantly (p < 0.001) increased risk of chronic rejection and associated graft loss. Inclusion of the liver was a significant predictor of better outcome (p = 0.004, HR = 0.347) with significant clearance of preformed antibodies (p = 0.04, OR = 56) and lower induction of de novo DSA (p = 0.07, OR = 24). Innovative multifaceted anti-DSA strategies are required to further improve long-term survival particularly of liver-free allografts.
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Affiliation(s)
- K M Abu-Elmagd
- Department of Surgery Department of Pathology, Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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36
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Zachary AA, Vega RM, Lucas DP, Leffell MS. HLA antibody detection and characterization by solid phase immunoassays: methods and pitfalls. Methods Mol Biol 2012; 882:289-308. [PMID: 22665241 DOI: 10.1007/978-1-61779-842-9_17] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solid phase immunoassays for the detection and characterization of HLA-specific antibodies provide greatly increased sensitivity, specificity, and time and reagent efficiency, compared to the traditionally used cell-based methods. Testing is performed using commercially available test kits. The assays are of two general types: enzyme-linked immunosorbent assays and multianalyte bead. The types vary in both sensitivity and equipment requirements.While these assays afford great improvement over the cell-based assays, they can be confounded by interference from substances within the serum that result in high background reactivity. The high sensitivity of the assays also makes them more susceptible to environmental factors and operator variability. The user must be aware of the capabilities of the various formats, the factors that can affect test results, and lot to lot variability of any single product. Knowledge of the characteristics of each product and thorough and accurate analysis of the results are essential to the utility of these assays.
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Affiliation(s)
- Andrea A Zachary
- Immunogenetics Laboratory, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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37
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Liu C, Wetter L, Pang S, Phelan DL, Mohanakumar T, Morris GP. Cutoff values and data handling for solid-phase testing for antibodies to HLA: Effects on listing unacceptable antigens for thoracic organ transplantation. Hum Immunol 2012; 73:597-604. [DOI: 10.1016/j.humimm.2012.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/05/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
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38
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Picascia A, Grimaldi V, Zullo A, Infante T, Maiello C, Crudele V, Sessa M, Mancini FP, Napoli C. Current Concepts in Histocompatibility During Heart Transplant. EXP CLIN TRANSPLANT 2012; 10:209-18. [DOI: 10.6002/ect.2011.0185] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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39
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Moreno C, Burgos L, Pérez-Robles C, Delgado JA, Mata JJ, Errasti P, Martín P, Merino J, Sánchez-Ibarrola A. Predictive value of the Luminex single antigen panel for detecting flow cytometry cross-match positivity. Hum Immunol 2012; 73:517-21. [DOI: 10.1016/j.humimm.2012.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 02/21/2012] [Accepted: 02/27/2012] [Indexed: 02/01/2023]
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40
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41
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Bartel G, Schwaiger E, Böhmig GA. Prevention and treatment of alloantibody-mediated kidney transplant rejection. Transpl Int 2011; 24:1142-55. [PMID: 21831227 DOI: 10.1111/j.1432-2277.2011.01309.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Antibody-mediated rejection (AMR), which is commonly caused by preformed and/or de novo HLA alloantibodies, has evolved as a leading cause of early and late kidney allograft injury. In recent years, effective treatment strategies have been established to counteract the deleterious effects of humoral alloreactivity. One major therapeutic challenge is the barrier of a positive pretransplant lymphocytotoxic crossmatch. Several apheresis- and/or IVIG-based protocols have been shown to enable successful crossmatch conversion, including a strategy of peritransplant immunoadsorption for rapid crossmatch conversion immediately before deceased donor transplantation. While such protocols may increase transplant rates and allow for acceptable graft survival, at least in the short-term, it has become evident that, despite intense treatment, many patients still experience clinical or subclinical AMR. This reinforces the need for innovative strategies, such as complementary allocation programs to improve transplant outcomes. For acute AMR, various studies have suggested efficiency of plasmapheresis- or immunoadsorption-based protocols. There is, however, no established treatment for chronic AMR and the development of strategies to reverse or at least halt chronic active rejection remains a big challenge. Major improvements can be expected from studies evaluating innovative therapeutic concepts, such as proteasome inhibition or complement blocking agents.
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Affiliation(s)
- Gregor Bartel
- Department of Medicine III, Medical University Vienna, Vienna, Austria
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42
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Positive virtual crossmatch with negative flow crossmatch results in two cases. Transpl Immunol 2011; 25:77-81. [DOI: 10.1016/j.trim.2011.05.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 11/20/2022]
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43
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Willicombe M, Brookes P, Santos-Nunez E, Galliford J, Ballow A, Mclean A, Roufosse C, Cook HT, Dorling A, Warrens AN, Cairns T, Taube D. Outcome of patients with preformed donor-specific antibodies following alemtuzumab induction and tacrolimus monotherapy. Am J Transplant 2011; 11:470-7. [PMID: 21299828 DOI: 10.1111/j.1600-6143.2010.03421.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has been shown that low-level preformed donor-specific antibodies (DSAbs) detected by luminex beads in the setting of a negative CDC and flow cytometry crossmatch (CDC/FCXM) are associated with inferior allograft outcomes. The relevance of preformed DSAbs in patients receiving alemtuzumab induction and tacrolimus monotherapy has not been studied. Four hundred and eighty renal transplant recipients with a negative CDC/FCXM had their pretransplant sera retrospectively screened for DSAbs. 45/480 (9.4%) of patients were found to have preformed DSAbs. Females and patients receiving regrafts were more likely to have a DSAb (p = 0.008 and p < 0.0001, respectively). Patients with DSAbs had inferior allograft survival (p = 0.047), increased incidence of antibody-mediated rejection (p < 0.0001) and inferior allograft function at 6 months posttransplant (p = 0.017). Patients with HLA class I DSAb (alone or in combination with a Class II DSAb) with high mean fluorescence intensities (MFIs) were at highest risk. We conclude that patients with preformed DSAb are at high risk of adverse outcomes when receiving a minimal immunosuppressive regime incorporating alemtuzumab induction. Patients found to have a preformed DSAb despite a negative crossmatch might benefit from augmented immunosuppression.
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Affiliation(s)
- M Willicombe
- Imperial College Kidney and Transplant Institute, Hammersmith Hospital, London, UK.
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44
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Amico P, Hirt-Minkowski P, Hönger G, Gürke L, Mihatsch MJ, Steiger J, Hopfer H, Schaub S. Risk stratification by the virtual crossmatch: a prospective study in 233 renal transplantations. Transpl Int 2011; 24:560-9. [PMID: 21332582 DOI: 10.1111/j.1432-2277.2011.01235.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The virtual crossmatch (virtual-XM) has been proposed for accurate identification of donor-specific HLA-antibodies, but large prospective studies assessing its value for pretransplant risk stratification are lacking. A total of 233 consecutive renal allograft recipients were prospectively stratified according to the virtual-XM. In patients with a negative virtual-XM (n=190, 82%), prospective cytotoxicity crossmatches (CDC-XM) were omitted, and they received standard immunosuppression. Virtual-XM positive patients were only transplanted if CDC-XM were negative. They received additional induction with anti-T-lymphocyte-globulin and intravenous immunoglobulins (n=43, 18%). The cumulative incidence of clinical/subclinical antibody-mediated rejection (AMR) at 1 year was lower in the negative virtual-XM than in the positive virtual-XM group [15/190 (8%) vs. 18/43 (42%); P<0.0001]. After a median follow-up of 2.6 years, allograft loss because of AMR occurred less often in the negative virtual-XM group (1% vs. 7%; P=0.04) and death-censored allograft survival at 2 years was higher (98% vs. 91%; P=0.02). Serum creatinine was not different at the last follow-up (129 μm vs. 130 μm; P=0.58). We conclude that a negative virtual-XM defines patients at low risk for AMR and early allograft loss, while a positive virtual-XM represents a significant risk for AMR despite enhanced induction therapy. This supports the utility of the virtual-XM for risk stratification and treatment allocation.
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Affiliation(s)
- Patrizia Amico
- Transplantation Immunology and Nephrology, University Hospital Basel, Petersgraben 4, Basel, Switzerland
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45
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Abstract
PURPOSE OF REVIEW As human leukocyte (HLA) antigen and antibody testing has evolved, typing, screening, and crossmatching assays have become exquisitely specific and sensitive. How best to use this information is a focal point of the transplant community and of this review. RECENT FINDINGS Driven by advances in technology, two major changes in the transplant community recently occurred. Firstly, the United Network for Organ Sharing mandated the use of cPRA to replace the more subjective panel reactive antibody value. Secondly, the virtual crossmatch (vXM) became a reality. The vXM categorizes sensitized patients as compatible or incompatible with their donors by predicting the likelihood of a positive crossmatch. Although the use of cPRA and vXM represents major progress in organ allocation algorithms, there are compelling issues that must be addressed. These include defining appropriate threshold values for antibody assignment and recognizing the relevance of antibodies to HLA-Cw*, HLA-DQ*, and HLA-DP*. SUMMARY Undoubtedly, molecular HLA-typing and solid-phase antibody-detection assays have revolutionized clinical histocompatibility testing. These new testing methodologies have had a major impact in both allocation and outcome of transplanted kidneys. However, even these new methodologies are not flawless and pose new challenges to the transplant community.
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46
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Abstract
For most solid organ and selected stem cell transplants, antibodies against mismatched HLA antigens can lead to early and late graft failure. In recognition of the clinical significance of these antibodies, HLA antibody identification is one of the most critical functions of histocompatibility laboratories. Early methods employed cumbersome and insensitive complement-dependent cytotoxicity assays with a visual read-out. A little over 20 years ago flow cytometry entered the realm of antibody detection with the introduction of the flow cytometric crossmatch. Cytometry's increased sensitivity and objectivity quickly earned it popularity as a preferred crossmatch method especially for sensitized recipients. Although a sensitive method, the flow crossmatch was criticized as being "too sensitive" as false positive reactions were a know drawback. In part, the shortcomings of the flow crossmatch were due to the lack of corresponding sensitive and specific HLA antibody screening assays. However, in the mid 1990s, solid phase assays, capable of utilizing standard flow cytometers, were developed. These assays used microparticles coated with purified HLA molecules. Hence, the era of solid-phase, microparticle technology for HLA antibody detection was born permitting the sensitive and specific detection of HLA antibody. It was now possible to provide better correlation between HLA antibody detection and the flow cytometric crossmatch. This flow-based technology was soon followed by adaptation to the Luminex platform permitting a mutltiplexed approach for the identification and characterization of HLA antibodies. It is hoped that these technologies will ultimately lead to the identification of parameters that best correlate with and/or predict transplant outcomes.
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47
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Bächler K, Amico P, Hönger G, Bielmann D, Hopfer H, Mihatsch MJ, Steiger J, Schaub S. Efficacy of induction therapy with ATG and intravenous immunoglobulins in patients with low-level donor-specific HLA-antibodies. Am J Transplant 2010; 10:1254-62. [PMID: 20353473 DOI: 10.1111/j.1600-6143.2010.03093.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Low-level donor-specific HLA-antibodies (HLA-DSA) (i.e. detectable by single-antigen flow beads, but negative by complement-dependent cytotoxicity crossmatch) represent a risk factor for early allograft rejection. The short-term efficacy of an induction regimen consisting of polyclonal anti-T-lymphocyte globulin (ATG) and intravenous immunoglobulins (IvIg) in patients with low-level HLA-DSA is unknown. In this study, we compared 67 patients with low-level HLA-DSA not having received ATG/IvIg induction (historic control) with 37 patients, who received ATG/IvIg induction. The two groups were equal regarding retransplants, HLA-matches, number and class of HLA-DSA. The overall incidence of clinical/subclinical antibody-mediated rejection (AMR) was lower in the ATG/IvIg than in the historic control group (38% vs. 55%; p = 0.03). This was driven by a significantly lower rate of clinical AMR (11% vs. 46%; p = 0.0002). Clinical T-cell-mediated rejection (TCR) was significantly lower in the ATG/IvIg than in the historic control group (0% vs. 50%; p < 0.0001). Within the first year, allograft loss due to AMR occurred in 7.5% in the historic control and in 0% in the ATG/IvIg group. We conclude that in patients with low-level HLA-DSA, ATG/IvIg induction significantly reduces TCR and the severity of AMR, but the high rate of subclinical AMR suggests an insufficient control of the humoral immune response.
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Affiliation(s)
- K Bächler
- Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland
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