Living-Donor Kidney Transplant With Preformed Donor-Specific Antibodies.

OBJECTIVES: We investigated outcomes in living-donor kidney transplant recipients with preformed donor-specific antibodies (detected with flow cytometry and specified with the LABScreen single antigen test) under desensitization pretransplant and immunosuppression posttransplant.

MATERIALS AND METHODS: Of 15 recipients included, 8 had ABO-incompatible kidney transplant. Six patients had sensitization caused by pregnancy, 8 by blood transfusion, 5 by previous transplants, and 1 by unknown cause. Desensitization was initiated using calcineurin inhibitors, methylprednisolone, and mycophenolate mofetil 30 days pretransplant, with rituximab administered 1 and 10 days pretransplant. Patients underwent plasmapheresis 1, 3, and 5 days pretransplant. Antithymocyte globulin was admi nistered for 5 days posttransplant as induction therapy. At 3 and 12 months posttransplant, all recipients underwent protocol renal allograft biopsies, with donor-specific antibodies simultaneously measured with the single antigen test.

RESULTS: T-cell complement-dependent cytotoxicity crossmatch was negative in all 15 recipients, but T-cell and B-cell flow cytometry was positive in 8 and 14 recipients, respectively. Anti-HLA class I antibodies became negative, except in 1 recipient 3 months posttransplant. Class II antibodies remained positive in 8 recipients 3 months posttransplant. No clinical or subclinical T-cell-mediated rejection occurred, but 1 recipient experienced clinical acute antibody-mediated rejection. At 3 and 12 months posttransplant, 8 and 5 recipients had subclinical acute antibody-mediated rejection. Cytomegalovirus test showed positivity in 14 recipients, but none developed cytomegalovirus disease. BK viremia was detected in 2 recipients, with 1 developing BK virus nephropathy, which was reversed by reducing immunosuppression.

CONCLUSIONS: Transplant patients with preformed donor-specific antibodies showed good outcomes in terms of desensitization and immunosuppression. However, most anti-HLA class II donor-specific antibodies remained, and microvascular inflammation score could indicate long-term risk of renal allograft dysfunction.