Stepwise minimization of the immunosuppressive therapy in pediatric liver transplantation. A conceptual approach towards operational tolerance.

The evolution of immunosuppression in pediatric liver transplantation has been characterized by a steady reduction of the immunosuppressive load, including removal of anti-lymphocyte antibodies, with the aim to reduce the incidence of EBV-related post-transplant lymphoproliferative disorders. Acute rejection rates were studied retrospectively over two decades of pediatric liver transplantation, according to the successive immunoprophylactic regimens. 318 primary pediatric liver transplant recipients, included between 1984 and 2004 in successive prospective trials, were analyzed, with respect to the impact of the immunosuppressive protocol on acute rejection occurrence. A progressive decrease of rejection incidences was observed, which corresponded to reduced immunosuppressive load and to transplant eras. Such trend might be related to changing approaches towards acute rejection histology and therapy by transplant clinicians, but also to the stepwise minimization of immunosuppressive protocols, putatively enhancing graft acceptance. We hypothesize that the recent population of liver transplant recipients with low immunosuppression might be more suitable for progressive immunosuppression withdrawal trial, with the aim to reach ultimately operational tolerance.