title: Risk factors for polyoma virus nephropathy.
abstract: BACKGROUND
  Polyoma virus-associated nephropathy (PVN) is a common cause of renal transplant failure. The risk factors for the development of PVN have not yet been studied in large cohorts of patients for periods of 20 years.
  
  
  METHODS
  We collected clinical, renal biopsy and urinary cytology data from all patients with renal transplantations performed at the University Hospital of Basel from 1985 to 2005. All patients with a renal biopsy and urine cytology were included (n = 880). Renal transplants were divided into three groups, according to evidence of polyoma virus (PV) infection (decoy cells in the urine) and biopsy-proven PVN: Renal transplants without evidence of a PV infection (n = 751). Renal transplants with PV reactivation, e.g. decoy cell (DC) found by urinary cytology, but without PVN (n = 90). Renal transplants with PVN (n = 39).
  
  
  RESULTS
  The prevalence of biopsy-proven PVN in this cohort of patients was 3.3%. Immunosuppression with mycophenolate and/or tacrolimus, ATGAM, male gender of the recipient and a higher number of transplant rejection episodes were factors significantly associated with PVN development.
  
  
  CONCLUSIONS
  The most important risk factors for the development of PVN are acute rejection and ATGAM used as induction therapy as well as tacrolimus and mycophenolate as maintenance therapy. Therefore, we conclude that patients with tacrolimus and mycophenolate maintenance therapy should be carefully monitored for the development of PVN.
authors.affiliation: Geriatric Medicine, University Hospital Basel, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Prince
authors.forename: Spasenija
authors.initials: S
authors.lastname: Savic
authors.forename: Michael
authors.initials: M
authors.lastname: Dickenmann
authors.forename: Jürg
authors.initials: J
authors.lastname: Steiger
authors.forename: Lukas
authors.initials: L
authors.lastname: Bubendorf
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mihatsch
mesh_terms: D015331:Cohort Studies; D005260:Female; D006085:Graft Survival; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology / Q000601:surgery / Q000821:virology*; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D011120:Polyomavirus; D027601:Polyomavirus Infections / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D014412:Tumor Virus Infections / Q000453:epidemiology*