title: BK virus-associated nephropathy in sirolimus-treated renal transplant patients: incidence, course, and clinical outcomes.
abstract: BACKGROUND
  Because the course of polyoma virus-associated nephropathy (PVAN) has not been evaluated in a large cohort of patients receiving sirolimus (SRL)-based regimens, we have herein presented the incidence, clinical characteristics, and outcomes of 378 renal transplant recipients treated with SRL-based immunosuppression.
  
  
  METHODS
  This retrospective single center study evaluated 344 kidney alone (KTX) and 34 simultaneous pancreas-kidney (SPK) transplantations performed between June 2000 and December 2004.
  
  
  RESULTS
  At a mean follow-up of 43.3 months, six kidney (1.7%) and three kidney-pancreas (9.0%) transplanted patients displayed biopsy-proven PVAN. The mean time to diagnosis after transplantation was 18.2 months (range: 3.5-31.1 months), with a higher incidence among patients exposed (4.23%) versus not exposed to rabbit antithymocyte globulin (rATG; 0.53%; P=0.019) or SPK (9.0%) versus KTX (1.7%) recipients (odds ratio: 5.43; confidence interval: 1.29-22.8; P=0.038). Despite treatment with cidofovir, reduced immunosuppression and maintenance therapy with no agents other than SRL (C0=10.2+/-2.7 ng/dL) plus modest doses of prednisone (< or =5 mg), five patients (55.5%) experienced renal allograft failure. No rejection episodes were documented during the PVAN treatment and pancreatic function continued to be excellent among the SPK patients.
  
  
  CONCLUSIONS
  Patients treated with SRL-based immunosuppression showed an incidence at the lower end of the range described with various other contemporaneous immunosuppressive regimens and with other cohorts not undergoing BK virus polymerase chain reaction surveillance. Exposure to rATG and SPK transplantation represented risk factors for the occurrence of PVAN, which showed a pernicious course despite withdrawal of calcineurin antagonists and/or mycophenolate mofetil.
authors.affiliation: Division of Immunology and Organ Transplantation, Department of Surgery, University of Texas Medical School at Houston, Houston, TX, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Benavides
authors.forename: Vida B
authors.initials: VB
authors.lastname: Pollard
authors.forename: Shamila
authors.initials: S
authors.lastname: Mauiyyedi
authors.forename: Hemangshu
authors.initials: H
authors.lastname: Podder
authors.forename: Richard
authors.initials: R
authors.lastname: Knight
authors.forename: Barry D
authors.initials: BD
authors.lastname: Kahan
mesh_terms: D000328:Adult; D000818:Animals; D000961:Antilymphocyte Serum / Q000009:adverse effects / Q000627:therapeutic use; D001739:BK Virus; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D015994:Incidence; D007674:Kidney Diseases / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology / Q000821:virology*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D016035:Pancreas Transplantation / Q000009:adverse effects; D027601:Polyomavirus Infections / Q000150:complications*; D011817:Rabbits; D012189:Retrospective Studies; D012307:Risk Factors; D020123:Sirolimus / Q000627:therapeutic use*; D014184:Transplantation, Homologous; D014412:Tumor Virus Infections / Q000150:complications*
chemical_list: D000961:Antilymphocyte Serum; D007166:Immunosuppressive Agents; D020123:Sirolimus