A Phased Desensitization Protocol With Rituximab and Bortezomib for Highly Sensitized Kidney Transplant Candidates

UNLABELLED Desensitization protocols comprising plasmapheresis, IVIGs, and rituximab and/or bortezomib have allowed for successful kidney transplantation in some highly HLA-sensitized patients with end-stage renal disease. However, the optimal combination of these therapies and their proper timing remains entirely unknown. We propose a phased desensitization strategy using rituximab followed by bortezomib as a safer method. METHODS Three sensitized kidney transplant candidates who could not be desensitized using our conventional protocol, which consists of a single rituximab dose combined with plasmapheresis, were enrolled in this study. When IgM(+) CD27(-) naive B cells reappeared but IgM(+) CD27(+) memory B cells remained undetectable in their peripheral blood, the patients were treated with 1 cycle of bortezomib followed by plasmapheresis. RESULTS After bortezomib treatment, patients' donor-specific anti-HLA antibodies (DSA) values were decreased, and cross-match tests were consistently negative. All 3 patients underwent living donor kidney transplantation. They showed immediate renal function, and both DSA and non-DSA were undetectable during the observation period. Neither antibody-mediated rejection nor severe acute cellular rejection was encountered in these patients after transplantation. CONCLUSIONS The present cases suggest that a phased use of rituximab and bortezomib can safely desensitize highly sensitized kidney transplant candidates.