Retreatment by antithymocyte globulin for second kidney transplantation: efficacy, tolerance and safety.

BACKGROUND: It is unknown whether kidney transplant patients who receive rabbit antithymocyte globulin (rATG) become immunized against rabbit antibodies, leading to reduced efficacy, or are at higher risk of cytomegalovirus infection or post-transplant lymphoproliferative disorder (PTLD) on retreatment. The efficacy and tolerance of rATG when used as induction for the second time in patients undergoing retransplantation have not been evaluated. METHODS: In a retrospective case-control study, 54 retransplanted patients who received rATG (Thymoglobulin) induction for the second time during 2004-2010 were compared to a matched cohort of 108 patients receiving rATG induction for a first kidney transplantation during the same period. Maintenance treatment was similar in both groups. RESULTS: Median follow-up was 45.8 months and 47.3 months in the second and first treatment groups, respectively. No differences were observed between the two groups in terms of leukocyte, lymphocyte or platelet depletion. Dose and duration of rATG treatment were similar in both groups, suggesting a similar tolerance profile. Cytomegalovirus infection (including primoinfection and reactivation) occurred in 4/54 retreated patients versus 22/108 controls (p=0.108). Use of cytomegalovirus prophylaxis was similar between groups. PTLD occurred in one control patient and no retreated patients. CONCLUSION: A second course of rATG induction results in similar lymphocyte depletion and is as well tolerated as a first course. The incidence of cytomegalovirus infection and post-transplant lymphoproliferative disease was not increased during retreatment. Further studies are required to evaluate specific T cell subpopulation depletion and compare long-term outcome in patients receiving a second induction with rATG.