Should living-unrelated renal transplant recipients receive antibody induction? Results of a clinical experience trial

Background. Living-donor kidney transplant recipients generally do not receive antibody induction. Induction avoidance may not be appropriate, particularly for living-unrelated renal transplant (LURT) recipients, in whom matching may not be optimal. We compared the incidence of acute rejection and graft outcome of LURT recipients who were administered no induction and cadaveric renal transplant (CRT) recipients who were administered anti-CD25 antibody. These groups both had immediate graft function and similar maintenance immunosuppression. Methods. This retrospective analysis included patients who received kidney transplants between 1999 and 2000. CRT recipients received basiliximab, corticosteroids, mycophenolate mofetil (MMF), and delayed tacrolimus (serum creatinine <3 mg/dL). LURT recipients received tacrolimus (initiated pretransplantation), MMF, and corticosteroids. Results. The analysis included 136 LURT recipients and 126 CRT recipients. CRT recipients included more African Americans (52.4% vs. 30.9% P<0.01). LURT recipients included more patients with at least one human leukocyte antigen mismatch (97.8% vs. 85.7%, P<0.01). A higher acute rejection rate was observed in LURT recipients at both 6 months (LURT recipients 19.1% vs. CRT recipients 3.2%, P<0.01) and 1 year (21.3% vs. 4.0%, P<0.0004); a higher rate also was observed in African American LURT recipients compared with African American CRT recipients (35.7% vs. 4.5%, P<0.0015) at I year. LURT recipients demonstrated a threefold greater rejection risk than CRT recipients who were administered basiliximab (relative risk: 3.6, P<0.002). Graft survival was similar at 1 year. Conclusion. The higher rejection rates in LURT recipients (no induction) compared with CRT recipients (basiliximab induction), despite similar chronic immunosuppression (tacrolimus, MMF, and steroids) and immediate graft function, indicate the potential advantage of anti-CD25 induction in LURT protocols to reduce the risk of acute rejection.