Donor-Derived AA Amyloidosis in a Kidney Allograft

Introduction: AA amyloidosis in renal allograft is an exceptionally rare occurrence. It typically arises in the context of chronic inflammatory or infectious diseases. We present a distinctive case of AA amyloidosis in a renal allograft. Case Description: A 62-year-old man with end-stage kidney disease secondary to diabetes mellitus underwent a preemptive deceased donor kidney transplant. Immunosuppresion consisted of thymoglobulin and methylprednisolone, followed by belatacept, mycophenolate mofetil and prednisone. Post-transplant serum creatinine (Cr) improved to 2.5 mg/dl. Urine-protein creatinine ratio (UPCR) improved to 3.97 g/g compared to 6.08 g/g pre-transplant. Five months post-transplant, the Cr increased to 3.95 mg/dl and UPCR increased to 9.36 g/g. Allograft biopsy showed Banff 1A acute cellular rejection (ACR), moderate expansion of mesangium and glomerular capillary walls by an amorphous pink material with apple-green birefringence on Congo red stain, signifying amyloid deposition. Liquid chromatography-tandem mass spectrometry analysis revealed AA type amyloid. The patient had no known chronic inflammation, infection, or autoimmune disorder. The donor had a history of intravenous drug use and died of necrotizing pneumonitis. The mate kidney thrombosed within a week of being implanted and required explantation. Donor kidney biopsy at the time of donation revealed eosinophilic material in the glomeruli, which in hindsight may have represented amyloidosis. The clinical impression was donor-derived AA amyloidosis. His ACR was treated with corticosteroids. Repeat biopsy confirmed resolution of acute rejection but kidney function worsened, and hemodialysis was initiated 7 months after transplantation. Discussion: Donor-derived AA amyloidosis in a kidney allograft has not been reported. Despite successful treatment of acute rejection, the patient developed graft failure. This complication may be avoidable by thorough pathologic evaluation of donor biopsy prior to transplantation.Note the deposition of amorphous pink material in the glomerulus