Bortezomib alone fails to decrease donor specific anti-HLA antibodies: 4 case reports.

In renal transplant recipients, the persistence of donor specific anti-HLA antibodies (DSA) associated with antibody-mediated graft injuries predicts evolution toward chronic humoral rejection and lower graft survival. Targeting plasma cells with the proteasome inhibitor bortezomib may be a promising desensitization strategy. We evaluated the in vivo efficacy of one cycle of bortezomib (1.3 mg/m2 x 4 doses), used as the sole desensitization therapy, in four renal transplant recipients experiencing sub-acute antibody-mediated rejection with persisting DSA (>2000 [Mean Fluorescence Intensity] MFI). Bortezomib treatment did not significantly decrease DSA MFI within the 270-day post-treatment period in any patient. In conclusion, one cycle of bortezomib alone does not decrease DSA levels in sensitized kidney transplant recipients.