Rewriting Unacceptable Antigens: HLA Delisting to Permit Transplantation - A Clinical Case Report

Abstract

Highly sensitized kidney transplant candidates experience limited access to compatible donors, prolonged waiting times, and increased mortality while on dialysis due to broad anti-human leukocyte antigen (HLA) antibody reactivity. Advances in immunologic assessment, particularly single-antigen bead assays, have enabled more precise characterization of donor-specific antibodies (DSAs) and facilitated risk-adapted strategies such as antigen delisting, in which low-level or clinically insignificant antibodies are reclassified as acceptable to expand donor compatibility. We report the case of a 67-year-old woman with end-stage kidney disease secondary to autosomal dominant polycystic kidney disease and a calculated panel reactive antibody (cPRA) of 100%, who remained on the transplant waiting list for 12 years without a suitable living donor. Following implementation of a structured delisting protocol, low-intensity class I DSAs with a mean fluorescence intensity below 2000 were reclassified as acceptable, reducing her PRA to 99.75% and enabling a successful deceased-donor kidney transplantation. Induction immunosuppression included antithymocyte globulin, tacrolimus, mycophenolate mofetil, corticosteroids, and intravenous immunoglobulin, with adjunctive rituximab given her elevated immunologic risk. Although early postoperative hypotension required transient dialysis support, no evidence of rejection was documented. Donor-specific antibodies became undetectable after transplantation, and at three months, she exhibited excellent graft function with normal creatinine and minimal proteinuria. This case illustrates that individualized antigen-delisting strategies combined with intensified immunosuppression and careful immunologic risk stratification can safely expand transplant access for highly sensitized patients, offering improved outcomes and a meaningful survival advantage compared with continued dialysis.