INDUCTION IMMUNOSUPPRESSION

K. Samy¹, M. Rees², S. Selman², D. Malhotra², D. Kaw², S. Ratnam², J. Shapiro^2
1, University of Toledo, Toledo/OH/UNITED STATES OF AMERICA, ², University of Toledo Medical Center, Toledo/OH/UNITED STATES OF AMERICA

Body: Background: Basiliximab (Simulect) blocks the IL-2 receptor (CD25) preventing T-helper cell signaling. Alemtuzumab (Campath 1-H) is an anti-CD52 antibody, inducing a lymphocyte and macrophage depleted state. In our experience, Campath induction allowed for a steroid-free post-transplant immunosuppressive regimen. We compare Simulect induction followed by standard three drug immunosuppression with Campath induction followed by steroid-free immunosuppression.

Methods: Data was collected retrospectively from patients transplanted between 1/1/2005 to 12/31/2007. Exclusion criteria limited transplants to two surgeons and the two specific drug regimens, resulting in a total study population of 184 patients. The first group underwent Simulect induction (88 patients), followed by cyclosporine (target trough level 250 ng/ml), mycophenolate mofetil (Cellcept 1 g PO bid), and prednisone maintenance. The Campath induction group (96 patients) was given tacrolimus (Prograf, target trough level 8-12 ng/ml) and mycophenolic acid (Myfortic 720 mg bid). Data collection included demographics, graft/patient survival, biopsy proven rejection episodes, and creatinine levels. Rejections were assessed for Banff score and the presence of a humoral component. The information was analyzed using SAS statistical software.

Results: Review of the study populations showed no significance differences between the two immunosuppression groups for demographic details, death censored graft survival, patient survival, graft survival, rejection rate, one or two year creatinine level, severity of rejection (Banff score) or humoral rejection. Death-censored graft survival rates after one year were 95.2% and 89.4% in the Simulect and Campath induction groups respectively. Two year death-censored graft survival was 91.4%, and 85.6% respectively. Patient survival with Simulect induction was 92.0% (one year) and 88.6% (two years). Patient survival with Campath induction was 95.8% (one year) and 90.6% (two years). Overall rejection rates were calculated to be 12.5% (one year) and 19.3% (two years) for the Simulect group. Campath rejection rates were 15.6% (one year) and 19.8% (two years). When rejection occurred, humoral rejection was slightly more prevalent in the Simulect group (31.5% vs 25.0%), but showed no statistical significance. Analysis for ethnicity was also performed. After two years, the rejection rate for Caucasians was 20.0% (Simulect) and 22.5% (Campath); the rate for African Americans was 23.0% (Simulect) and 13.0% (Campath). Creatinine level at one year was 1.6+0.6 mg/dL (Simulect) and 1.5+0.6 mg/dL (Campath) and at two years was 1.7+0.8 mg/dL (Simulect) and 1.5+0.4 mg/dL (Campath).

Conclusion: In this small, retrospective study, graft survival, patient survival and rejection rates were not statistically different between Campath induction followed by steroid free immunosuppression and Simulect induction followed by triple drug immunosuppression. While there was a trend toward lower graft survival in the Campath groups, lower patient survival in the Simulect group may have impaired our ability to detect differences in graft failure before death. Rejections in the Campath group demonstrated a unique acellular tubulitis and/or vasculitis not adequately represented in the Banff score. Based on these studies, our transplant program continues to use Campath induction with steroid-free maintenance immunosuppression and longer term studies of these two immunosuppressive approaches are ongoing.

Disclosure: All authors have declared no conflicts of interest.