Applying virtual crossmatch approach in portuguese kidney transplants

ORAL SESSIONS - Best AbstractsPresence of donor specific antibodies anti-human leukocyte antigen (HLA) is generally a contra-indication for transplantation and nowadays the identification of these antibodies are part of most pre-transplantation evaluations. In Portugal, the implemented protocol for the registration and maintenance of the active list for kidney transplant includes a complement-dependent cytotoxity (CDC) panel-reactive antibody (PRA) screening method, and Luminex technology for detecting and characterizing HLA alloantibodies. Under the current Portuguese kidney allocation system from deceased donors, implemented in August 2007, deceased donor kidneys are primarily allocated via ABO identical and time on dialysis with extra points to hyperimmunized patients, namely PRA CDC>50%. Additional risk for the candidate or transplant organ can be represented by a proposed calculated PRA (cPRA) based upon unacceptable HLA antigens detected by Luminex to which the patient has been sensitized. These unacceptable HLA antigens used to generate cPRA represents a ‘virtual’ crossmatch (XM). Sensitized patients are less likely to be matched with a suitable donor organ. Even after clearing the hurdle of procuring a living donor, it is still possible that this is not sufficient due to the likelihood of having a XM-positive. In these cases and in the presence of incompatible blood type between recipients and their intended living donors, kidney paired donation (KPD) can provide an answer by facilitating exchanges between willing donors’ kidneys. A national Portuguese KPD program, when realized, may prevent the current loss of a significant number of suitable living donors and reduce waiting list time for a deceased donor. An upgrade of a suggested point system in a Portuguese KPD program will be the use of cPRA instead of the values of PRA CDC. In Portugal, the virtual XM approach simply represents the optimization of an existing technique