LAUSR

Introduction BK viremia is rarely reported in non-kidney solid organ transplant recipients. We present a case of a heart transplant recipient with BK viremia. We highlight the challenges of treating BK viremia in a patient with multiple post-transplant morbidities. Case Report Our patient is a 16 year old male with history of complex single ventricle anatomy status post heart transplant due to failing Fontan physiology with protein losing enteropathy (PLE). His early post-transplant course was complicated by continued PLE, post-transplant lymphoproliferative disorder (PTLD), and acute kidney injury requiring temporary hemodialysis for nine months. Three years post-transplant, he presented with worsening renal function and proteinuria in the setting of relapsed PTLD. Serum BK virus was found to be positive at high viral loads. Antiviral therapy with leflunomide was initiated. He underwent renal biopsy that showed 70% glomerulosclerosis with BK inclusions consistent with BK virus nephritis. Adjunct therapy with cidofovir was started, but was discontinued due to its side effect of nephrotoxicity. He is currently undergoing treatment with rituximab and virus specific T-cells to both Epstein-barr and BK viruses with a promising initial response. This patient's history of chronic kidney disease and long-term immunosuppressive therapy including multiple exposures to nephrotoxic agents makes the decision of how to treat his BK viremia a challenge. Summary BK viremia in post heart transplant recipients is not commonly reported, but poses a challenge to management given the limited therapeutic options available. Development of standard monitoring protocols as well as refinement of treatment options is necessary in this patient population that is at high risk for acute and chronic kidney injury.