Bortezomib Treatment for Refractory Antibody-Mediated Rejection Superimposed with BK Virus-Associated Nephropathy during the Progression of Recurrent C3 Glomerulonephritis

A 38-year-old man, who underwent a second kidney transplantation (KT), was admitted because of antibody-mediated rejection (AMR) complicated by BK virus-associated nephropathy (BKVAN). He was placed on hemodialysis at the age of 24 years because of membranoproliferative glomerulonephritis. At the age of 28 years, he underwent a living donor KT from his father; however, 1 year after the transplantation, he developed a recurrence of the primary glomerular disease, resulting in graft failure 2 years after the first KT. Ten years later, he received a deceased-donor kidney with a B-cell-positive-cross-match. He received 600 mg of rituximab before the KT with three cycles of plasmapheresis and immunoglobulin (0.5 g/kg) therapy after KT. During the follow-up, the first and second allograft biopsies at 4 and 10 months after KT revealed AMR with a recurrence of primary glomerular disease that was reclassified as C3 glomerulonephritis (C3GN). He received a steroid pulse, rituximab, plasmapheresis, and immunoglobulin therapies. The third allograft biopsy demonstrated that the BKVAN was complicated with AMR and C3GN. As the azotemia did not improve after repeated conventional therapies for AMR, one cycle of bortezomib ($1.3mg/m^2{\times}4\;doses$) was administered. The allograft function stabilized, and BK viremia became undetectable after 6 months. The present case suggests that bortezomib therapy may be applicable to patients with refractory AMR, even in cases complicated with BKVAN.