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Abdo RCT, Gobbi RG, Leite CBG, Pasoto SG, Leon EP, Lima ALLM, Bonfa E, Pécora JR, Demange MK. Quantitative alpha-defensin testing: Is synovial fluid dilution important? World J Orthop 2022; 13:760-767. [PMID: 36159623 PMCID: PMC9453281 DOI: 10.5312/wjo.v13.i8.760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 02/04/2022] [Accepted: 08/05/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Alpha-defensin has been widely studied for the diagnosis of periprosthetic joint infection (PJI). However, there is a lack of detailed information regarding the proper laboratory technique of the enzyme-linked immunosorbent assay (ELISA) method, such as sample dilution.
AIM To assess the influence of dilution in the synovial fluid during ELISA for the diagnosis of knee PJI; and determine which dilution presents a better performance.
METHODS Forty samples of synovial fluid from arthroplasty knees were included, 17 in the infected group and 23 in the aseptic group, according to Musculoskeletal Infection Society criteria. Initially, five synovial fluid samples from each group were assessed for quantitative analysis of alpha-defensin using ELISA. Different dilution ratios (1:10, 1:100, 1:500, 1:1000 and 1:5000) were tested based on the predetermined cutoff value of 5.2 mg/L. The dilutions that performed better were used to compare the results of all samples.
RESULTS For infected cases, a gradual increase in the dilution of synovial fluid samples led to an equivalent increase in alpha-defensin level. The same was not observed in the aseptic cases. Both 1:1000 and 1:5000 dilutions presented satisfactory results to differentiate infected and aseptic cases. Further analyses were performed using 1:1000 and 1:5000 for all 40 samples. The 1:1000 dilution resulted in a sensitivity of 88.2% (95%CI, 66%-98%) and specificity of 95.7% (95%CI, 79%-99%), whereas the 1:5000 dilution presented a sensitivity of 94.1% (95%CI, 73%-99%) and a specificity of 100% (95%CI, 86%-100%).
CONCLUSION The synovial fluid dilution had an important influence on the alpha-defensin ELISA results. Dilutions of 1:5000 showed the best performance for the diagnosis of knee PJI. The results of this study set the basis for a more reliable and reproducible alpha-defensin ELISA during the investigation of PJI, contributing to the expansion of this technique in different treatment centers worldwide.
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Affiliation(s)
- Rodrigo Calil Teles Abdo
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
- Orthopaedic Department, HCor - Hospital do Coração, Sao Paulo 04004-030, Brazil
| | - Riccardo Gomes Gobbi
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
- Orthopaedic Department, HCor - Hospital do Coração, Sao Paulo 04004-030, Brazil
| | - Chilan Bou Ghosson Leite
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - Sandra Gofinet Pasoto
- Division of Rheumatology, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - Elaine Pires Leon
- Division of Rheumatology, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - Ana Lucia Lei Munhoz Lima
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - Eloisa Bonfa
- Division of Rheumatology, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - José Ricardo Pécora
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
| | - Marco Kawamura Demange
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
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Kim JK, Bae H, Ko GY, Lee J, Jung J, Jekarl DW, Choi AR, Lee S, Chung BH, Yang CW, Park SC, Oh EJ. Successful ABO-incompatible living donor kidney transplantation in a recipient who developed flow cytometry crossmatch-positive donor-specific class I HLA antibodies following COVID-19 vaccination. HLA 2022; 100:52-58. [PMID: 35484951 DOI: 10.1111/tan.14649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/29/2022] [Accepted: 04/26/2022] [Indexed: 11/28/2022]
Abstract
The effects of COVID-19 vaccination on alloimmunization and clinical impact in transplant candidates remain largely unknown. In a 61-year-old man who had no donor-specific antibodies (DSA) and was planned to undergo ABO-incompatible kidney transplantation (ABOi KT), DSAs (anti-A24, anti-B51, anti-Cw14) developed after COVID-19 vaccination. After desensitization therapy, antibody level was further increased, leading to flow cytometric crossmatch-positive status. Donor-specific T cell immunity using interferon-gamma ELISPOT was continuously negative, whereas SARS-CoV-2 specific T cell immunity was intact. After confirming the C1q-negative status of DSA, the patient received ABOi KT. The patient had stable graft function and suppressed alloimmunity up to two months after KT. COVID-19 vaccination might relate to alloimmunization in transplant candidates, and desensitization through immune monitoring can help guide transplantation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jae Kwon Kim
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hyunjoo Bae
- Department of Biomedical Science, Graduate School, the Catholic University of Korea, Seoul, Korea
| | - Geon Young Ko
- Department of Biomedical Science, Graduate School, the Catholic University of Korea, Seoul, Korea
| | - Jihyun Lee
- Department of Biomedical Science, Graduate School, the Catholic University of Korea, Seoul, Korea
| | - Jin Jung
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Research and Development Institute for In Vitro Diagnostic Medical Devices of Catholic University of Korea, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Dong Wook Jekarl
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Research and Development Institute for In Vitro Diagnostic Medical Devices of Catholic University of Korea, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ae-Ran Choi
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sangyoon Lee
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Byung Ha Chung
- Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chul Woo Yang
- Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sun Cheol Park
- Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Eun-Jee Oh
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.,Research and Development Institute for In Vitro Diagnostic Medical Devices of Catholic University of Korea, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Norin AJ, Das B, Mondragon-Escorpizo MO, Bajaj H, Sumrani N, John D, Salifu MO. Determination of unacceptable antigens by summation of anti-HLA eplet antibody strength (MFI) based on single antigen bead assays: Excellent correlation with negative cell based cross matches. Hum Immunol 2022; 83:482-493. [DOI: 10.1016/j.humimm.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 11/04/2022]
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Filippone EJ, Gulati R, Farber JL. Noninvasive Assessment of the Alloimmune Response in Kidney Transplantation. Adv Chronic Kidney Dis 2021; 28:548-560. [PMID: 35367023 DOI: 10.1053/j.ackd.2021.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/28/2021] [Accepted: 08/26/2021] [Indexed: 11/11/2022]
Abstract
Transplantation remains the optimal mode of kidney replacement therapy, but unfortunately long-term graft survival after 1 year remains suboptimal. The main mechanism of chronic allograft injury is alloimmune, and current clinical monitoring of kidney transplants includes measuring serum creatinine, proteinuria, and immunosuppressive drug levels. The most important biomarker routinely monitored is human leukocyte antigen (HLA) donor-specific antibodies (DSAs) with the frequency based on underlying immunologic risk. HLA-DSA should be measured if there is graft dysfunction, immunosuppression minimization, or nonadherence. Antibody strength is semiquantitatively estimated as mean fluorescence intensity, with titration studies for equivocal cases and for following response to treatment. Determination of in vitro C1q or C3d positivity or HLA-DSA IgG subclass analysis remains of uncertain significance, but we do not recommend these for routine use. Current evidence does not support routine monitoring of non-HLA antibodies except anti-angiotensin II type 1 receptor antibodies when the phenotype is appropriate. The monitoring of both donor-derived cell-free DNA in blood or gene expression profiling of serum and/or urine may detect subclinical rejection, although mainly as a supplement and not as a replacement for biopsy. The optimal frequency and cost-effectiveness of using these noninvasive assays remain to be determined. We review the available literature and make recommendations.
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Kang H, Yoo J, Lee SY, Oh EJ. Causes of Positive Pretransplant Crossmatches in the Absence of Donor-Specific Anti-Human Leukocyte Antigen Antibodies: A Single-Center Experience. Ann Lab Med 2021; 41:429-435. [PMID: 33536364 PMCID: PMC7884190 DOI: 10.3343/alm.2021.41.4.429] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/20/2020] [Accepted: 11/24/2020] [Indexed: 01/25/2023] Open
Abstract
Pretransplant crossmatch (XM) testing is widely used for detecting preformed donor-specific antibodies (DSAs) against human leukocyte antigen (HLA). However, in some cases, there is a positive XM result in the absence of HLA-DSAs, the cause of which was rarely identified. We reviewed the causes of sequential positive XM results at a single center and analyzed the presence of non-HLA antibodies in patients with an unexplained positive pretransplant XM result. Among 251 patients with T-cell/B-cell complement-dependent cytotoxicity (CDC) or flow cytometric crossmatch (FCXM) positivity, HLA-DSAs were confirmed in 88 (35.1%) by a single antigen bead (SAB) assay, 150 (59.8%) used rituximab (anti-CD20), and 13 (5.2%) had neither HLA-DSAs nor a desensitization history. Anti-angiotensin II type 1 receptor IgG and 33 non-HLA antibodies were tested in the 13 patients with an unexplained positive pretransplant XM result, and more than one non-HLA antibody were revealed in all these patients; 11 patients had non-HLA antibodies reported to be associated with graft rejection, and two patients experienced rejection episode after kidney transplantation. Our study suggests considering non-HLA antibodies testing when a CDC or FCXM test is positive without a definite cause. Assessing non-HLA antibodies might be useful for interpreting XM results and evaluating immunologic risk in transplant recipients.
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Affiliation(s)
- Hyunhye Kang
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jaeeun Yoo
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang-Yoon Lee
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Eun-Jee Oh
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Yoo J, Lee S, Lee HW, Lee S, Choi J, Han J, Kang H, Choi A, Hee Jang J, Oh EJ. Assessment of Rapid Optimized 96-well Tray Flow Cytometric Crossmatch (Halifax-FCXM) with Luminex Single Antigen Test. Hum Immunol 2021; 82:302-308. [PMID: 33744026 DOI: 10.1016/j.humimm.2021.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Flow cytometric crossmatch assay (FCXM) is a sensitive cell-based method for evaluating the presence of donor-specific antibodies (DSA) before transplantation. Recently, 96-well tray FCXM protocol (Halifax FCXM) with improved test efficiency has been introduced. The objective of the present study was to assess the performance of Halifax FCXM by correlating with DSA results based on single antigen bead (SAB) assays (virtual crossmatch, VXM). METHODS A total of 341 FCXMs were evaluated for the detection of HLA-DSA. A positive VXM was defined as having at least one HLA - DSA (HLA-A, B, Cw, DR, DQB1) with ≥ 1000 MFI (mean fluorescence intensity) identified by SAB assay. RESULTS Of a total 341 cases, 113 showed class I VXM (+) with class I DSA MFI ≥ 1000 exclusively against one or more donor HLA class I antigens (HLA-A, B, Cw), 72 had class I-/II + DSA, and 156 had VXM(-). Halifax T-FCXM showed a sensitivity of 87.6% (99/113) and a specificity of 98.2% (224/228) for detecting class I VXM (+). The concordance between T-FCXM and class I VXM was 94.7% (323/341). Halifax B-FCXM showed a sensitivity of 58.3% (42/72) and a specificity of 98.7% (154/156) for detecting class I-/II + DSAs. The concordance between B-FCXM and class I-/II + VXM was 86.0% (196/228). When we separately analyzed data, B-FCXM detected HLA-DR (+) (68.8%) and HLA-DQ (+) DSAs (71.0%) similarly (P > 0.05). T-FCXM detected 87.6%, 97.2%, and 98.2% of class I DSA-positive cases with MFI values (sumDSA) ≥ 1000, ≥ 3000, and ≥ 5000, respectively. B-FCXM detected 58.3% of class I-II + DSA -positive (≥1000) cases, but detected 76.7% (33/43) and 89.2% (33/37) of class I-II + DSAs if MFI values of sumDSA and immunodominant DSA (iDSA) were above 5000, respectively. Halifax FCXM had sensitivities of 91.5% and 96.2% for detecting VXM (+) having MFI values above 5000 for class I or class II sumDSA and iDSA, respectively. CONCLUSION Halifax FCXM showed a good correlation, especially with SAB assay-based high MFI DSA or sumDSA. Concurrent application of FCXM with VXM can improve pre-transplant risk assessment and progress organ allocation efficiency.
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Affiliation(s)
- Jaeeun Yoo
- Department of Laboratory Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Sangyoon Lee
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Ho Won Lee
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Soojung Lee
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Jieun Choi
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Jaeho Han
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Hyunhye Kang
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Aeran Choi
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Joo Hee Jang
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea
| | - Eun-Jee Oh
- Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea.
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Launhardt K, Lefevre V, Souplet V, Prantl L, Marget M, Hovoricova B, Wenda S, Olivier C. Concordance with established tests and reproducibility of results obtained with a new single antigen chip array for HLA antibody detection (HISTO SPOT® HLA AB). J Immunol Methods 2021; 491:112971. [PMID: 33549571 DOI: 10.1016/j.jim.2021.112971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 12/30/2020] [Accepted: 01/21/2021] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to analyze performance of a new single antigen chip array system (HISTO SPOT® HLA AB) developed for HLA antibody detection and compare with results obtained using single antigen Luminex-based systems and serum samples from the Eurotransplant external proficiency testing scheme. Results were analysed from 11 independent Eurotransplant laboratories using HISTO SPOT® HLA AB utilising the Eurotransplant external proficiency testing (EPT) sera and these were compared to published results from 67 labs using the Luminex-based technologies. In addition, QC results from different batches of the test were analysed. Generally, concordance of results with the results from the Luminex technique was good. With the Luminex tests more consensus results and more questionable results were found than with the HISTO SPOT® HLA AB test. Within the HISTO SPOT® HLA AB testing group we found a discrepancy rate from the consensus of 2.9% for the EPT sera which is far below the 25% allowed to pass the quality test and only slightly higher than for the Luminex single antigen tests with 1.2%. The average global coefficient of variation (CV) of the mean signal (raw data) for the HISTO SPOT® HLA AB test was 13% which is lower than the values reported for Luminex tests in the literature. The average global CV for the signal/background ratio was higher with 28%. In the present study, the mean signal is the best parameter to compare results between labs and the new HISTO SPOT® HLA AB test is at least as good in terms of signal reproducibility as the Luminex tests. In conclusion, the HISTO SPOT® HLA AB test is a good alternative to be used in addition or instead of the Luminex tests in clinical labs.
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Affiliation(s)
| | | | - Vianney Souplet
- Innobiochips, 70, rue du Docteur Yersin, 59 120 Loos, France
| | - Livia Prantl
- Central Institute for Blood Transfusion and Immunology, University Hospital, Anichstr. 35, 6020 Innsbruck, Austria
| | - Matthias Marget
- Institute for Transfusion Medicine, University Hospital Hamburg Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Blanka Hovoricova
- University Hospital F. D. Roosevelta Banska Bystrica, Department of Laboratory Hematology - HLA Laboratory, Namestie L. Svobodu 1, 975 17, Banska Bystrica, Slovakia
| | - Sabine Wenda
- Medical University Vienna, University Hospital for Blood Group Serology and Transfusion Medicine, Währinger Gürtel 18-20 / Ebene 4i, 1090 Vienna, Austria
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Investigating complement mediated interference in class I HLA-specific antibodies following renal transplantation. Transpl Immunol 2020; 62:101310. [PMID: 32574596 DOI: 10.1016/j.trim.2020.101310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Single antigen bead testing (SAB) for HLA-specific antibody enables efficient organ allocation and aids in the diagnosis of antibody mediated rejection. In this retrospective cohort study, a population of kidney transplant recipients possessing HLA Class I antibodies was used to evaluate the best method for resolving complement interference, the so called "prozone" effect. The aim was to compare the use of EDTA versus a Biotin-Streptavidin Complex as methodological approaches for abating the prozone effect using a fixed 1 in 10 dilution as validation. METHODS One hundred and seventeen patients transplanted in our centre between 2009 and 2014 were identified as having class I HLA-specific antibody(-ies) using a Labscreen® Mixed assay. Positive sera underwent class I HLA-specific SAB testing; for comparison a standard SAB with and without EDTA, BSC and dilution (1 in 10) modifications were utilised. Samples were processed on the Luminex platform generating 11,349 bead reactions for analysis. RESULTS We identified sera from 23 patients giving rise to 170 bead reactions showing complement interference. Using linear modelling, we observed slightly higher MFIs on average in both EDTA and BSC modifications when compared to the standard assay, allowing the nominal threshold MFI of 2000 in the standard assay to be adjusted to 2097 and 2033 in the EDTA and BSC assays respectively. We calculated 99% prediction intervals to establish outlier bead reactions for each assay. The 1 in 10 dilution was used as a crosscheck for determining which prozone reactions were overcome by EDTA and BSC. Using ROC curve analysis, EDTA was found to be ~90% sensitive and 100% specific compared to BSC which was ~60% sensitive and 100% specific in ameliorating prozone positive reactions at the thresholds defined by linear models. DISCUSSION Our data indicates that both EDTA and BSC are suitable assays in overcoming CMI. We recommend that all clinical laboratories adopt a validated assay designed specifically to abrogate CMI for all potential renal transplant recipients, as the standard assay is inhibited in nearly 20% of a post-transplant cohort.
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Development of data-driven models for the flow cytometric crossmatch. Hum Immunol 2019; 80:983-989. [PMID: 31530432 DOI: 10.1016/j.humimm.2019.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/13/2019] [Accepted: 09/05/2019] [Indexed: 01/08/2023]
Abstract
HLA laboratories use virtual crossmatching (VXM) to predict recipient and donor compatibility using HLA antibody data and donor HLA type. Increasingly, transplant centers are utilizing VXM as the final compatibility determination prior to transplant. However, the VXM interpretation is based on HLA experience of individual transplant centers. This study developed data-driven algorithms that predicted flow cytometric crossmatch (FCXM) outcomes using HLA antibody mean fluorescent intensity (MFI) data and donor HLA typing without the need for human interpretation.Two algorithms were evaluated; an MFI Optimal-Threshold model and a Least-Squares-Fitting model. The Optimal-Threshold model correctly determined between 81.5% and 85.5% of T or B-cell responses. A class I antibody MFI threshold of 4670 was optimal for predicting T-cell response while an antibody MFI threshold of 6180 was optimal for predicting B-cell responses. HLA class I antibodies had a 1.47-fold greater influence on FCXM outcomes than class II antibodies. HLA-B antibodies influenced T and B-cell responses more than HLA-A or -C (-B > -A > -C). The Least-Squares-Fitting model increased accuracy to 94.1% and 88.8% for T and B-cell responses, respectively. The algorithms described here provide enhanced FCXM prediction and novel insights into the influence of specific HLA antibodies on the crossmatch outcome.
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