Sirolimus-based immunosuppression for transplant-associated thrombotic microangiopathy.

Abstract

Thrombotic microangiopathy (TMA) is a well-recognized complication of solid organ transplanta-tion. Both calcineurin inhibitors cyclosporine [1] andtacrolimus [2] have been associated with TMA.Treatment strategies for TMA have included plasma-pheresis [1,2], calcineurin inhibitor dose reduction[1,2], calcineurin inhibitor withdrawal [1,2], and con-version from one calcineurin inhibitor to the other [3].However, calcineurin inhibitor dose reduction or dis-continuation increases the risk of acute allograft rejec-tion and recurrent TMA has been described in patientsthat were converted from cyclosporine to tacrolimus[4,5]. We present two cases of biopsy-proven trans-plant-associated TMA that were successfully treatedby discontinuation of tacrolimus followed by the useof sirolimus, mycophenolate mofetil (MMF) andprednisone for the prevention of allograft rejection.