Single fixed low-dose rituximab as induction therapy suppresses de novo donor-specific anti-HLA antibody production in ABO compatible living kidney transplant recipients

This study was conducted to evaluate de novo donor-specific anti-human leukocyte antigen (HLA) antibody (dnDSA) production leading to antibody-mediated rejection (ABMR) after rituximab induction in non-sensitized ABO-compatible living kidney transplantation (ABO-CLKTx). During 2008-2015, 318 ABO-CLKTx were performed at the Department of Surgery III at Tokyo Women's Medical University Hospital. To reduce confounding factors, we adopted a propensity score analysis, which was applied with adjustment for age, gender, duration of pretransplant dialysis, HLA mismatch count, preformed DSA, non-insulin-dependent diabetes mellitus, immunosuppressive treatment, and estimated glomerular filtration rate (eGFR) on postoperative day 7. Using a propensity score matching model (1:1, 115 pairs), we analyzed the long-term outcomes of 230 ABO-CLKTx recipients retrospectively. Recipients were classified into a rituximab-treated (RTX-KTx, N = 115) group and a control group not treated with rituximab (C-KTx, N = 115). During five years, adverse events, survival rates for grafts and patients, and incidence of biopsy-proven acute rejection (BPAR) and dnDSA production for the two groups were monitored and compared. All recipients in the RTX-KTx group received rituximab induction on preoperative day 4 at a single fixed low dose of 100 mg; the CD19+ B cells were eliminated completely before surgery. Of those recipients, 13 (11.3%) developed BPAR; 1 (0.8%) experienced graft loss. By contrast, of C-KTx group recipients, 25 (21.7%) developed BPAR; 3 (2.6%) experienced graft loss. The RTX-KTx group exhibited a significantly lower incidence of BPAR (P=.041) and dnDSA production (13.9% in the RTX-KTx group vs. 26.9% in the C-RTx group, P=.005). Furthermore, lower incidence of CMV infection was detected in the RTX-KTx group than in the C-KTx group (13.9% in the RTX-KTx group vs. 27.0% in the C-KTx group, P=.014). No significant difference was found between groups for several other factors: renal function (P=.384), graft and patient survival (P=.458 and P=.119, respectively), and the respective incidences of BK virus infection (P=.722) and leukopenia (P=.207). During five-year followup, single fixed low-dose rituximab therapy is sufficient for ensuring safety, reducing rejection, and suppressing dnDSA production for immunological low-risk non-sensitized ABO-CLKTx.