title: Frequency of Polyomavirus BK Infection in Kidney Transplant Patients Suspected to Nephropathy.
abstract: BACKGROUND
  Polyomavirus BK is a major cause of nephropathy in immunosuppressed transplanted patients. Non-invasive diagnostic protocols such as molecular detection of polyomavirus BK replication are a useful strategy to predict BK virus-associated nephropathy (BKVAN).
  
  
  OBJECTIVE
  To determine the prevalence of polyomavirus BK infection among kidney transplant patients suspected to have BKVAN.
  
  
  METHODS
  In a cross-sectional study 108 kidney transplanted patients whose laboratory and clinical presentation were in favor of nephropathy between 2010 and 2012, were enrolled for analysis. Polyomavirus BK replication was evaluated in plasma and tissue samples of studied patients using a quantitative real-time PCR. Active cytomegalovirus infection was analyzed in studied patients using antigenemia method. A possible association between polyomavirus BK infection with clinical and laboratory risk factors of BKVAN were evaluated.
  
  
  RESULTS
  The polyomavirus BK replication was found in 17 (15.7%) of 108 of plasma and 9 (11%) of 82 tissue samples in kidney transplanted patients. Cytomegalovirus co-infection was found in 3 of 17 and 3 of 9 plasma and tissue samples in polyomavirus BK infected patients, respectively. Significant associations were found between polyomavirus BK infection with tubulointerstitial nephritis and acute cellular rejection, as important pathologic findings of BKVAN.
  
  
  CONCLUSIONS
  Diagnosis of single and co-infection of polyomavirus BK infection in plasma samples is a useful assay to evaluate the risk of BKVAN in kidney transplant patients. Established threshold values for studied viral infections have beneficial use in screening of kidney transplant patients at risk of BKVAN, need to confirm and standardized in completed further studies.
authors.affiliation: Department of Internal Medicine, Shiraz Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Pakfetrat
authors.affiliation: Shiraz Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: R
authors.initials: R
authors.lastname: Yaghobi
authors.affiliation: Department of Internal Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Z
authors.initials: Z
authors.lastname: Salmanpoor
authors.affiliation: Department of Internal Medicine, Shiraz Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: J
authors.initials: J
authors.lastname: Roozbeh
authors.affiliation: Pathology Department, Shiraz Nephrology-Urology Research Center, Shiraz Medical School, University of Medical Sciences, Shiraz, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Torabinezhad
authors.affiliation: Shiraz Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Kadkhodaei
keywords: Kidney transplantation; Nephropathy; Polyomavirus BK