Treatment of antibody-mediated rejection in kidney transplant recipients: a single-center experience with a bortezomib-based regimen.

Objectives: Antibody-mediated rejection after kidney transplant is less responsive to conventional antirejection therapies. The proteasome inhibitor bortezomib has activity against mature plasma cells that produce damaging donor-specific antibodies. We present our experience of using a bortezomib-based regimen in patients with severe antibody-mediated rejection.

Materials And Methods: A retrospective chart review was performed on patients with biopsy-proven antibody-mediated rejection after kidney transplant at our institution over 12 months. Diagnosis of antibody-mediated rejection was made on the basis of positive peritubular capillary C4d staining along with either histologic evidence of acute rejection or positive donor-specific antibody titers. Treatment for antibody-mediated rejection included plasmapheresis, intravenous immunoglobulin, steroids, single-dose rituximab (375 mg/m²) along with bortezomib (1.3 mg/m²) on days 1, 4, 8, and 11. Antibody-mediated rejection was diagnosed in 6 patients. Patients received induction with either alemtuzumab (n=4) or rabbit-antithymocyte globulin (n=2) and were maintained on a tacrolimus/mycophenolate mofetil/early steroid withdrawal protocol.

Results: Four of 6 patients responded to treatment. Patients had stable kidney function during followup (median 14 months) after bortezomib therapy.

Conclusions: In this series, we demonstrated the effectiveness of a bortezomib-based treatment regimen in achieving reduction of donor-specific antibody titers and stable renal function in patients experiencing severe antibody-mediated rejection.