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#119
MONITORING THE REMOVAL OF HLA ALLOANTIBODY USING LUMINEX MICROBEAD ARRAYS.
Mark Hathaway BSc MSc PhD 1, Robert Higgins MD 2, David P. Lowe BSc MSc 1 and David C. Briggs BSc PhD 1. 1 Histocompatibility & Immunogenetics, National Blood Service, Birmingham, United Kingdom and 2 Renal Unit, Walsgrave Hospital, Coventry, United Kingdom .
Background: Renal allografts transplanted in the presence of donor specific HLA alloantibodies are at risk of hyperacute rejection. Artificial antibody removal can render a positive crossmatch negative to allow a successful transplant. In order to monitor the efeectiveness of the removal process and to identify re-emergence of donor specific antibody following transplantation, a precise and rapid testing of antibody levels is required.
Methods: Two patients undergoing antibody removal by plasma exchange (PE) were studied. Each had antibody specific for HLA class II mismatches in their potential live donor (DR15 and DR53 respectively). Antibody specificity and levels were characterised using a luminex based assay.
Results: Using Luminex we were able to track quantitative and qualitative changes in donor specific antibodies during successive rounds of PE. Antibody specificity and level were reported within 3 hours of receiving a sample. Reductions in antibody level measured by Luminex correlated with both cytotoxic antibody titre and with strength of donor-specific crossmatch measured by FACS. We monitored one patient post-transplant and could clearly demonstrate the reemergence then modulation of donor-specific antibody despite the presence and sustained high level of third party specific antibody.
Conclusion: Monitoring antibody removal by Luminex is rapid and reliable and is a quicker and more consistent alternative to traditional cell-based methods of determining antibody strength. Evaluating antibody specificity and level in real time allows monitoring of antibody removal and the ability to respond effectively to post-transplant reemergence of donor-specific antibody.