A Case of De Novo Membranous Nephropathy Causing Renal Transplant Rejection.

We present a novel case of de novo membranous nephropathy (DNMN) leading to transplant rejection in a 51-year-old female patient. The patient has a transplant history of two renal transplants for end-stage renal disease due to lupus nephritis. She had a prior unrelated, living donor kidney transplant that was subsequently replaced by a deceased donor kidney transplant due to graft failure. This patient's case is intriguing because DNMN is a rare cause of transplant rejection, and the literature demonstrates a scarcity of clinical examples. Interestingly, post-transplant DNMN has been suggested to be a separate disease from recurrent post-transplant MN and is associated with separate risk factors and diagnostic findings. As DNMN is considered a manifestation of antibody-mediated rejection, it should be treated with immunosuppressive therapy. As such, the presented case has received immunosuppressive therapy. In addition, DNMN is associated with humoral alloimmunity. Potentially other inflammatory processes (such as infection/potential UTI in our patient's case) could cause exposure to undetectable donor antigens on renal transplants leading to antibody-mediated rejection via DNMN.