PF810 ABO INCOMPATIBLE KIDNEY TRANSPLANTATION – ONE CENTRE EXPERIENCE
Authors: M. Sampaio, M. Bini Antunes, J. Malheiro, L. Dias, L.S. Martins, S. Pedroso, M. Almeida, A. Castro Henriques, S. Tafulo, R. Oliveira, F. Vasconcelos, M. Amil
Journal: HemaSphere (2019)

Background: Donor living kidney transplantation (KT) is an available optionfor end‐stage renal disease, improving survival and quality of life when compared with other treatments. ABO incompatibility was considered an important barrier for long but, with the increasing organ shortage and due to improvement of immunosuppression protocols, ABO‐incompatible (ABOi) KT has achieved remarkable success in the last decades, with graft survivals and patient overall survivals comparable to compatible transplantations. Consensually, initial goal is to lower patient ABO antibodies titter to ≤1:16 before transplantation, ≤1:8 during the first week and ≤1:16 during the second week after surgery. Thereafter, even a rebound of ABO antibodies does not appear to harm the graft due to accommodation phenomenon. Current strategies for desensitization include B‐cell‐depleting therapies and intensified immunosuppression as well as plasmapheresis to remove ABO antibodies. Aims: Retrospective evaluation of donor/recipient pairs proposed for ABOi Kidney transplantation between 2015 and 2018. Methods: Donor‐patient pairs were proposed by the Kidney Transplantation Centre. Patients were evaluated for ABO/Rh group, relationship with donor, diagnosis, pre‐KT isoagglutinin anti‐A and anti‐B (IgG and IgM), pre‐KT donor specific HLA antibodies, post‐KT isoagglutinin titter (daily up to D14, at D30, and at sixth month after KT), number of plasmapheresis performed (target: IgG isoagglutinin &lt;1: 8 between D0‐D7 and &lt;1:16 to D14), graft function titter (serum creatinine), transfusion support, significant associated complications and overall patient survival. An initial IgG isoagglutinin titter ≥1: 512 was considered contraindication for KT as well as the presence of donor specific anti‐HLA antibodies. Immunosuppression protocol included rituximab and basiliximab for B cell depletion and standard triple immunosuppression with tacrolimus, mofetil mycophenolate and corticosteroids. Results: We studied 43 donor‐receptor pairs for ABOi‐KT over a period of four years. Sixteen patients were excluded due to ABO IgG titters ≥1:512 and 10 out of 17 pairs considered suitable for transplantation were transplanted in the considered period. Results are summarized in table 1. Graft survival so far is 100% on a follow‐up period between 7 and 49 months. All patients are independent from dialysis and the creatinine level has steady levels (average of 1.61 mg/dL). However, in one patient a renal biopsy performed at sixteenth month documented an incipient glomerulopathy, even if ABO titters maintained low and no evidence of HLA Ab was found out. Summary/Conclusion: The presented results are in accordance with those described by some authors and confirm that ABOi KT is a viable alternative for the treatment of patients with chronic kidney disease, permit to expand the living donor pool and to reduce the time access to transplantation. image