engleski

HLA-DP highly sensitized patient in acceptable mismatch program

Introduction Antibodies directed against donor mismatched Human Leukocyte Antigens (HLA) can cause graft loss after transplantation. Many studies describe the influence of donor-recipient HLA class I mismatches (MM) on transplant outcome, but effects of HLA class II MMs are still unknown, especially for HLA-DP locus. Some studies show that there are no deleterious effects of HLA-DP mismatching in first transplants, but that there is a significant impact on re-transplants. As avoiding such MMs is crucial for highly sensitized patients, the Eurotransplant Acceptable mismatch (AM) program has been initiated and is based on finding a donor with HLA antigens to which the patient has never made antibodies. Still, long term analysis revealed that most highly sensitized patients were most likely to die or be removed from the list than transplanted. This led to the development of clinical trials for desensitization therapies that would enable HLA-incompatible transplantation. European Medicines Agency has recently approved novel agent, the IgG-degrading enzyme (Imlifidase) that cleaves all four human subclasses of IgG and enables rapid degeneration of anti-HLA donor specific antibodies after drug administration. Case Study Here, we report a case of a 39-year-old female patient who received a first kidney transplant in 1990 from a deceased donor and suffered from graft rejection 12 years later. In January 2015 the patient received a second deceased donor transplant, but this graft failed right after the transplantation. Being a highly sensitized patient, with two previous cadaveric transplantations, pregnancy and transfusion, there were no suitable donor offers for her afterwards. All available living donors were excluded due to positive DSAs and strong positive crossmatch (CM), among which CM with father stood out as weak positive, probably due to lower titer of HLA class I DSAs. For all these reasons she applied for the AM program in which she was registered in November 2021. Since then, she got two kidney offers with no HLA-A, B, C, DR and DQ MMs, but both offers were rejected due to the poor organ quality. It still remains the question whether they would be suitable offers since there was no information on HLA-DP typing of the donors. The main challenge for this patient is high HLA-DP sensitization and whether she should be transplanted across HLA-DP DSAs and possibly a positive crossmatch. Conclusion Here we present a highly sensitized patient with a high HLA-DP sensitization that could be a candidate for Imlifidase administration in order to expand the pool of possible donors.

HLA-DP ; kidney transplantation ; acceptable mismatch program

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