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All Posts (17)

  • O.O.Adebiyi, J.Gralla, P.Klem, B.Freed, S.Davis, A.C.Wiseman and J.E.Cooper

    Introduction
    The widespread utilization of single-antigen bead (SAB) assays prior to kidney transplantation has improved the detection of donor-specific antibody (DSA) in potential transplant recipients. Many studies have documented inferior renal graft outcomes in the presence of pretransplant DSA (1–15). However, the clinical importance of such DSA in the setting of a negative flow cytometry crossmatch (FCXM) at transplant remains controversial and the need for desensitization uncertain. There are limited published data regarding the impact of specific DSA characteristics such as class, strength or whether DSA persisted posttransplant on renal allograft outcomes when flow cytometry is negative. Additionally, the clinical significance…

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  • Dolores Redondo-Pachón, Julio Pascual, María J.Pérez-Sáez, Carmen García, Juan José Hernández, Javier Gimeno, Marisa Mir, Marta Crespoa

    The influence of antibodies against HLA-DP antigens detected with solid-phase assays on graft survival after kidney transplantation (KT) is uncertain.We evaluated with Luminex®the prevalence of pre- and posttransplant DP antibodies in 440 KT patients and their impact on graft survival. For 291 patients with available pretransplant samples, DP antibodies were present in 39.7% KT with pretransplant HLA antibodies and 47.7% with DSA. Graft survival of KT with pretransplant class-II DSA was worse than with non-DSA (p= 0.01). DP antibodies did not influence graft survival. Of 346 patients monitored post-KT, 17.1% had HLA class-II antibodies, 56% with DP antibodies. Class-II DSA was detected in 39%, 60.9% of them had DP antibodies. Graft survival was…

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  • Craig J.Taylor, Vasilis Kosmoliaptsis, Jessie Martin, Graham Knighton, Dermot Mallon, J. Andrew Bradley, and Sarah Peacock

    Background. Solid-phase assays to distinguish complement binding from noncomplement binding HLA-specific antibodies have been introduced, but technical limitations may compromise their interpretation. We have examined the extent to which C1q-binding to HLA-class I single-antigen beads (SAB) is influenced by denatured HLA on SAB, antibody titre, and complement interference that causes a misleading low assessment of HLA-specific antibody levels. Methods. Sera from 25 highly sensitized patients were tested using Luminex IgG-SAB and C1q-SAB assays. Sera were tested undiluted, at 1:20 dilution to detect highlevel IgG, and after ethylene diamine tetraacetic acid treatment to obviate complement interference. Conformational HLA and denatured HLA…

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  • Glen P.Westall, and Greg I.Snell

    The lung transplant community continues to struggle with the diagnosis and management of antibody-mediated rejection. The four diagnostic tenets of donor-specific antibodies, C4d staining, histopathologic changes, and allograft dysfunction, which were largely derived from the early Banff meetings on renal transplantation, have somewhat arbitrarily been applied to lung transplantation. With the passage of time, it is increasingly apparent that merits of these diagnostic pillars are less robust in lung transplantation. In this article, we summarize some of the controversies and challenges surrounding the diagnosis of antibody-mediated rejection in lung transplantation.

    Keywords: Lung transplantation, Antibody-mediated rejection, Humoral rejection, Chronic lung allograft syndrome.…

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  • Anat R.Tambur, Jimmy Rosati, Shirley Roitberg, Denis Glotz, John J.Friedewald and Joseph R.Leventhal

    Background. Human leukocyte antigen (HLA)-DQ has emerged as the alloantibody most frequently associated with the generation of de novo donor-specific antibody (DSA), antibody-mediated-rejection, and unfavorable transplantation outcome.
    Methods. The generation of HLA-DQ de novo DSA was interrogated in 40 transplant recipients who were immunologically naive before their failed transplantation. Eplet and epitope analyses were performed using HLAMatchmaker and Cn3D software.
    Results. Ten DQA and thirteen DQB eplets or eplet combinations were identified. All but one revealed an epitope footprint that includes both the DQa and DQb chains. Four examples are illustrated in detail, representing a range of different epitope landscapes. A disparity between antigen…

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  • Jeremy M.Blumberg, Hans A.Gritsch, Elaine F.Reed, J.M.Cecka, Gerald S.Lipshutz, Gabriel M.Danovitch, Suzanne McGuire, David W.Gjertson and Jeffrey L.Veale

    Incompatible donor/recipient pairs with broadly sensitized recipients have difficulty finding a crossmatch-compatible match, despite a large kidney paired donation pool. One approach to this problem is to combine kidney paired donation with lower-risk crossmatch-incompatible transplantation with intravenous immunoglobulin. Whether this strategy is non-inferior compared with transplantation of sensitized patients without donor-specific antibody (DSA) is unknown. Here we used a protocol including a virtual crossmatch to identify acceptable crossmatch-incompatible donors and the administration of intravenous immunoglobulin to transplant 12 HLA-sensitized patients (median calculated panel reactive antibody 98%) with allografts from our kidney paired donation program.…

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  • Immunoassays announcement on ASHI site

    IMMUNOASSAYS WEBSITE

    In response to discussions at the 16th International Histocompatibility and Immunogenetics Workshop, members of the Johns Hopkins Immunogenetics Laboratory have created a website for all things related to solid phase antibody immunoassays.  At www.immunoassays.net, you can enter into discussions about test interpretation and troubleshooting. The site provides information on the latest assays, performance of different test lots, correlations between solid phase and cell based test results, and serum treatments.  There is information on bead assays, flow cytometry and ELISA as well as links to relevant publications. Please visit the website and become a member at www.immunoassays.net.  You can become a site moderator and lead discussions.  

    Source: …

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  • B.J.Orandi, J.M.Garonzik-Wang, A.B.Massie, A.A.Zachary, J.R.Montgomery, K.J.Van Arendonk, M.D.Stegall, S.C.Jordan, J.Oberholzer, T.B.Dunn, L.E.Ratner, S.Kapur, R.P.Pelletier, J.P.Roberts, M.L.Melcher, P.Singh, D.L.Sudan, M.P.Posner, J.M.El-Amm, R.Shapiro, M.Cooper, G.S.Lipkowitz, M.A.Rees, C.L.Marsh, B.R.Sankari, D.A.Gerber, P.W.Nelson, J.Wellen, A.Bozorgzadeh, A.O.Gaber, R.A.Montgomery and D.L.Segev

    Incompatible live donor kidney transplantation (ILDKT) offers a survival advantage over dialysis to patients with anti-HLA donor-specific antibody (DSA). Programspecific reports (PSRs) fail to account for ILDKT, placing this practice at regulatory risk. We collected DSA data, categorized as positive Luminex, negative flow crossmatch (PLNF) (n¼185), positive flow, negative cytotoxic crossmatch (PFNC) (n¼536) or positive cytotoxic crossmatch (PCC) (n¼304), from 22 centers.…

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  • J.G.O’Leary, A.J.Demetris, L.S.Friedman, H.M.Gebel, P.F.Halloran, A.D.Kirk, S.J.Knechtle, S.V.McDiarmid, A.Shaked, P.I.Terasaki, K.J.Tinckam, S.J.Tomlanovich, K.J.Wood, E.S.Woodle, A.A.Zachary and G.B.Klintmalm

    Several insights emerged. Acute antibody-mediated rejection (AMR), although rarely diagnosed, is increasingly understood to overlap with T cell–mediated rejection. Isolated liver allograft recipients are at increased risk of early allograft immunologic injury when preformed DSA are high titer and persist posttransplantation. Persons who undergo simultaneous liver–kidney transplantation are at risk of renal AMR when Class II DSA persist posttransplantation. Other under-appreciated DSA associations include ductopenia and fibrosis, plasma cell hepatitis, biliary strictures and accelerated fibrosis associated with recurrent liver disease. Standardized DSA testing and diagnostic criteria for both…

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  • Brian D.Tait, Caner Susal, Howard M.Gebel, Peter W.Nickerson, Andrea A.Zachary, Frans H.J.Claas, Elaine F.Reed, Robert A.Bray, Patricia Campbell, Jeremy R.Chapman, P.Toby Coates, Robert B.Colvin, Emanuele Cozzi, Ilias I.N.Doxiadis, Susan V.Fuggle, John Gill, Denis Glotz, Nils Lachmann, Thalachallour Mohanakumar, Nicole Suciu-Foca, Suchitra Sumitran-Holgersson, Kazunari Tanabe, Craig J.Taylor, Dolly B.Tyan, Angela Webster, Adriana Zeevi, and Gerhard Opelz

    Background. The introduction of solid-phase immunoassay (SPI) technology for the detection and characterization of human leukocyte antigen (HLA) antibodies in transplantation while providing greater sensitivity than was obtainable by complement-dependent lymphocytotoxicity (CDC) assays has resulted in a new paradigm with respect to the interpretation of donor-specific antibodies (DSA). Although the SPI assay performed on the Luminex instrument…

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  • Andrea A. Zachary, Mary S. Leffell

    Summary: Desensitization protocols are being used worldwide to enable kidney transplantation across immunologic barriers, i.e. antibody to donor HLA or ABO antigens, which were once thought to be absolute
    contraindications to transplantation. Desensitization protocols are also being applied to permit transplantation of HLA mismatched hematopoietic stem cells to patients with antibody to donor HLA, to enhance the opportunity for transplantation of non-renal organs, and to treat antibody-mediated rejection. Although desensitization for organ transplantation carries an increased risk of antibody-mediated rejection, ultimately these transplants extend and enhance the quality of life for solid organ recipients, and desensitization that permits transplantation of hematopoietic stem cells is life saving for patients with limited donor options. Complex patient factors and…

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  • Annette M. Jackson, Mary S. Leffell, Robert A. Montgomery, and Andrea A. Zachary

    Purpose of review
    To identify factors that affect the choice of route to renal transplantation for the sensitized patient. The evolution of protocols for transplanting sensitized patients has been desensitization (DES), paired donation, and most recently, paired donation combined with DES. Use of these protocols has revealed various factors that influence which route is the most likely to work for a given patient.
    Recent findings
    The data indicate that patient blood type and HLA sensitization have the dominant influence on what route is best for a patient but numerous other factors, particularly the number, HLA type, and ABO type of donors a patient brings to a program will also affect the likelihood of transplantation. The distribution of these factors among patients transplanted or unable…

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  • Robert A. Montgomery, Bonnie E. Lonze and Annette M. Jackson

    Purpose of review
    Many sensitized patients have willing live donors but are unable to use them because of a human leukocyte antigen (HLA) incompatibility. The options for these patients include: remaining on the deceased-donor list, entering a kidney-paired donation scheme, or undergoing desensitization with high-dose IVIg or plasmapheresis and low-dose IVIg.
    Recent findings
    Mathematical simulations verified by actual data from several national kidney-paired donation (KPD) programs has shed light on which donor/recipient phenotypes are likely to benefit from each transplant modality. Pairs that are easy to match are likely to receive compatible kidneys in a KPD. Those who are hard to match may be better served by desensitization. The phenotype which is both hard to match and hard to desensitize due to board and…

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  • Annette M. Jackson, Edward S. Kraus, Babak J. Orandi, Dorry L. Segev, Robert A. Montgomery and Andrea A. Zachary

    Rituximab has been used to increase the efficacy of desensitization protocols for human leukocyte antigen (HLA)-incompatible kidney transplantation; however, controlled comparisons have not been reported. Here we examined 256 post-transplant HLA antibody levels in 25 recipients desensitized with and 25 without rituximab induction, to determine the impact of B-cell depletion. We found significantly less HLA antibody rebound in the rituximab-treated patients (7% of donor-specific antibodies (DSAs) and 33% of non-DSAs) compared with a control cohort desensitized and transplanted without rituximab (32%
    DSAs and 55% non-DSAs). The magnitude of the increase was significantly larger among patients who did not receive rituximab. Interestingly,…

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  • Mary Carmelle Philogene, Paul Sikorski, Robert A. Montgomery, Mary S. Leffell, and Andrea A. Zachary

    Background. Bortezomib has been used to reduce HLA antibody in patients either before transplantation or as treatment
    for antibody-mediated rejection (AMR). Reports on its efficacy show mixed results. The mechanism of action
    of this agent is via proteasome inhibition. The primary route of synthesis of HLA class I molecules is dependent on
    peptide generation by the proteasome, whereas that of class II is not. We observed a differential effect of bortezomib on
    class I versus class II antibody and hypothesized that this was related to a reduced expression of class I HLA antigens.
    Methods. The effect of bortezomib on HLA antibody levels was evaluated in 13 patients who were desensitized for
    incompatible renal…

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  • Andrea A. Zachary , Renato M. Vega , Donna P. Lucas , and Mary S. Leffell

    Abstract
    Solid phase immunoassays for the detection and characterization of HLA-speci fi c antibodies provide greatly increased sensitivity, speci fi city, and time and reagent ef fi ciency, 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…

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  • Announcement:  Development of Solid Phase Immunoassay Collaborative Website*

    *The place to go for all things related to solid phase immunoassays

    To Include:

    • Collection of data on Luminex based assays
    • Summary of test performance
    • Identification of anomalous reactions with controls
    • Serum Treatments
    • MFI Correlations with Crossmatch testing
    • Discussion Boards/Blogs/Forums
    • Trending analyses of bead lots
    • Links to Human Immunology
    • Individual Sections for Single Antigen/Pooled Antigen/Screen Assays

    Part of the ongoing Evaluation of Antibody Frequencies and Solid Phase Assays of the

    15th & 16th International Histocompatibility Workshops

     

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