title: De novo tacrolimus-induced thrombotic microangiopathy in the early stage after renal transplantation successfully treated with conversion to everolimus.
abstract: BACKGROUND
  Calcineurin inhibitor (CNI)-induced thrombotic microangiopathy (TMA) is a rare complication after renal transplantation. It may be difficult to distinguish from CNI toxicity and acute antibody-mediated rejection (AMR). Its clinical presentation may vary from isolated localised forms up to catastrophic systemic presentations.
  
  
  METHODS
  We report a case of tacrolimus-induced TMA soon after renal transplantation in an 11-year-old boy who received his second renal transplantation. His first graft was lost because of AMR. On day 12 after his second renal transplantation, his renal function started worsening and a kidney biopsy was performed, which showed histopathological signs of TMA. The diagnosis of tacrolimus-induced TMA was established after excluding AMR and other causes of de novo TMA. Genetic complement investigation disclosed two complement factor H risk polymorphisms as possible modifiers of TMA emergence. Treatment was based on replacing tacrolimus with everolimus, with a subsequent normalisation of renal function.
  
  
  CONCLUSIONS
  A prompt diagnosis of de novo TMA by early allograft biopsy is essential for the allograft outcome and genetic investigations for possible complement abnormalities are reasonable, not only for patients with a systemic aspect of their post-transplant TMA. Replacing tacrolimus with everolimus effectively controlled the TMA and stabilised renal function in our patient.
authors.affiliation: Department of Paediatrics I, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria.
authors.forename: Gerard
authors.initials: G
authors.lastname: Cortina
authors.forename: Raphaela
authors.initials: R
authors.lastname: Trojer
authors.forename: Siegfried
authors.initials: S
authors.lastname: Waldegger
authors.forename: Stefan
authors.initials: S
authors.lastname: Schneeberger
authors.forename: Nadezda
authors.initials: N
authors.lastname: Gut
authors.forename: Johannes
authors.initials: J
authors.lastname: Hofer
mesh_terms: D065095:Calcineurin Inhibitors / Q000009:adverse effects*; D002648:Child; D057915:Drug Substitution; D000068338:Everolimus / Q000627:therapeutic use; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation; D008297:Male; D016559:Tacrolimus / Q000009:adverse effects*; D057049:Thrombotic Microangiopathies / Q000139:chemically induced* / Q000175:diagnosis
chemical_list: D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D000068338:Everolimus; D016559:Tacrolimus