Sirolimus exposure during the early post-transplant period reduces the risk of CMV infection relative to tacrolimus in renal allograft recipients

Introduction: There are limited data regarding the role of individual maintenance immunosuppressive agents in the development of cytomegalovirus (CMV) infection. We examined the association between exposure to sirolimus (SRL) and risk of CMV infection after kidney transplantation when compared with tacrolimus (TCL). Methods: This is a retrospective observational study of adult renal allograft recipients transplanted between 2001 and 2005 at our center. Patients received anti-lymphocyte antibody induction, and mycophenolate mofetil with either SRL or TCL prednisone. D + /R- patients received valganciclovir 900 mg/d and CMV + patients 450 mg/d for three months. CMV infection was diagnosed with pp65 antigenemia testing prompted by clinical suspicion. Results: A total of 14 Cases with CMV infection and 129 Controls were identified for primary analysis, and 11 D + /R- Cases and 19 D + /RControls for secondary analysis. The groups were comparable in both analyses, except for D + /R- serostatus in the primary analysis. All 14 Cases were on TCL for at least three months prior to diagnosis of CMV infection. In the primary analysis, zero Cases, but 30.2% and 34.9% of Controls (p = 0.009 and 0.004), and in secondary analysis, zero Cases, but 31.6% and 42. 1 % of Controls (p = 0.046 and 0.013), were on SRL at one and three months, respectively. In the primary analysis, zero Cases vs. 45 Controls (p = 0.004), and in secondary analysis, zero Cases vs. eight Controls (p = 0.013), were on SRL for at least three months early posttransplantation. Conclusion: These findings suggest that SRL as a component of a multidrug immunosuppressive regimen decreases the risk of CMV infection after kidney transplantation when compared with TCL.