Acute Rejection Mediated by Preformed Anti-HLA-C Antibody in a Kidney Transplant Patient: A Case Report.

Recently, the clinical relevance of donor-specific anti-HLA-C antibodies has been recognized in kidney transplantation (KT). In this case report, we describe the diagnosis and treatment response of acute antibody-mediated rejection in a patient with preformed anti-HLA-C. A 66-year-old male who had returned to hemodialysis 8 years prior, after losing his first living donor graft underwent a second KT with a standard deceased donor. He had an antibody reactivity panel of 99.8%, a negative crossmatch, and an identified anti-HLA-C antibody (11,032 mean fluorescence intensity). He presented with delayed graft function, and the biopsy showed acute antibody-mediated rejection positive for C4d. The episode was treated with 3 doses of methylprednisolone 500 mg/d, five plasmapheresis sessions, and 1 g/kg/d of human immunoglobulin for 2 days, with clinical, laboratory, and histological response, maintaining a GFR (CKD Epidemiology Collaboration 2021) of 93 mL/min/1.73 m² for 3 years after the KT. Considering the less frequent detection of anti-HLA-C antibodies and their potential to trigger rejection, which impacts kidney graft survival, this report and the published work on the topic reinforce the importance of evaluating their pathogenic role. With the recent recognition and understanding of the subject, early identification, and inclusion of HLA-C in routine typing will improve analysis of transplant conditions and rejection risk.