EVOLVING TRENDS IN ACUTE REJECTION AND CMV INFECTION EPISODES AMONG KIDNEY TRANSPLANT RECIPIENTS FROM 1995 TO 2003: A SINGLE-CENTER STUDY

Abstract

P351 Aims: Acute rejection and CMV infection episodes are two important risk factors in renal transplantation. We performed a retrospective study to determine the incidence of both events, and their evolution over time with respect to changes in immunosuppressive protocols and anti-CMV prophylaxis strategies. Methods: All patients who received kidney transplants at our institution from January 1995 to November 2003 (with the exception of those who died peri-operatively or did not have a minimal follow-up of at least 3 months) were included in the study. Immunosuppressive regimens were as follows: from 1995 to 1999 (period I), after various induction regimens, patients received CsA and prednisone. From 2000 to march 2003 (period II), basiliximab induction was followed by administration of CsA, prednisone +/- mycophenolate mofetil. Since April 2003 (period III), patients received basiliximab (or thymoglobuline) for induction, and then tacrolimus, prednisone and mycophenolate mofetil. Acute rejection episodes were defined for the purpose of the study by anti-acute rejection therapy (i.e., ≥3 daily pulses of methylprednisolone or antilymphocyte therapy). Acute rejection episodes had been diagnosed by the team based on clinical or histological criteria during the first 6 months after transplantation. No anti-CMV prophylaxis was prescribed during period I, whereas valaciclovir was administered to high risk patients (D+/R-) during period II, and valganciclovir to all D+/R-, D+/R+ and D-/R+ combinations during period III. For the monitoring of CMV infection, blood cultures (shell vial method) were performed weekly for the first 6 weeks and once every two weeks for the next 6 weeks. Weekly cultures for 4 weeks and biweekly cultures for an extra 4 weeks were proposed after the treatment of a rejection episode. CMV viremia was defined as a positive culture from blood leucocytes, and classified either as CMV infection (in the absence of symptoms) or CMV disease. Results: 208 patients underwent kidney transplantation, 126 in period I, 64 in period II and 18 in period III. CMV serostatus patterns were not significantly different between the 3 periods (D+/R- 17-24%; D+/R+ 39-50%; D-/R+ 22-35% and D-/R- 11-17%). Acute rejection episodes were treated in 73 patients (58%), 22 patients (34%) and 1 patient (6%) during period I, II and III, respectively (p<0.0001). CMV infection or disease was diagnosed in 82 (65%), 27 (42%) and 3 patients (17%) during period I, II and III, respectively (p<0.0001). Conclusions: We observed a marked decrease in the frequency of acute rejection episodes in period III when newer immunosuppressive combinations were introduced. Importantly, the simultaneous implementation of daily valganciclovir prophylaxis decreased incidence of CMV infection despite the more potent immunosuppressive therapy used.