Managing Concurrent Antibody-Mediated Rejection and BK Polyomavirus Nephropathy After Kidney Transplantation: Successful Treatment Using CD38 Blockade.

The coexistence of antibody-mediated rejection (AMR) and BK polyomavirus-associated nephropathy (BKPyVAN) represents a major therapeutic challenge after kidney transplantation. Whereas treatment of AMR typically requires intensification of immunosuppression, management of BKPyVAN relies on reduction of immunosuppressive therapy to restore antiviral immune control. We report a kidney transplant recipient who developed active AMR with de novo donor-specific antibodies and concurrent BKPyVAN 12 weeks after transplantation. Given ongoing BKPyV replication, recent infectious complications, and concerns regarding further escalation of conventional immunosuppressive therapy, the patient was treated with pulse methylprednisolone followed by anti-CD38 therapy using daratumumab. Treatment resulted in recovery of allograft function, disappearance of donor-specific antibodies, and complete histological resolution of AMR. BKPyV replication subsequently declined and ultimately resolved without recurrent rejection. This case highlights CD38 blockade as a potential therapeutic option in selected patients with concomitant AMR and BKPyVAN. However, given the concurrent administration of corticosteroids and optimization of maintenance immunosuppression, these findings should be regarded as hypothesis-generating.