title: Polyomavirus nephropathy: quantitative urinary polyomavirus-Haufen testing accurately predicts the degree of intrarenal viral disease.
abstract: BACKGROUND
  A qualitative highly predictive urinary test for polyomavirus nephropathy (PVN) is the PV-Haufen test. This article evaluates whether a quantitative PV-Haufen analysis, that is, the number of PV-Haufen shed per milliliter urine, predicts PVN disease grades and the severity of intrarenal PV replication.
  
  
  METHODS
  Polyomavirus-Haufen were counted in 40 urine samples from patients with biopsy-proven definitive PVN. The number of PV-Haufen was correlated with both histologic PVN disease grades 1 to 3 and the number of SV40-T-expressing cells as indicators of intrarenal PV replication in corresponding renal allograft biopsies (manual counts and automated morphometry). Findings from quantitative PV-Haufen analyses were compared to conventional laboratory test results, that is, BK viremia (quantitative polymerase chain reaction [PCR]) and BK viruria (quantitative PCR and decoy cell counts).
  
  
  RESULTS
  Polyomavirus-Haufen counts showed excellent correlation (α0.77-0.86) with the severity of intrarenal PV replication and disease grades. In particular, low PV-Haufen numbers strongly correlated with early PVN grade 1 and minimal intrarenal expression of SV40-T antigen (P < 0.001). In comparison, BK viremia and viruria levels by PCR showed only modest correlations with histologic SV40-T expression (α0.40-0.49) and no significant correlation with disease grades or minimal intrarenal PV replication. No correlations were seen with urinary decoy cell counts. In contrast to conventional quantitative PCR assays or decoy cell counts, quantitative urinary PV-Haufen testing accurately reflects the severity of PV replication, tissue injury, and PVN disease grades.
  
  
  CONCLUSIONS
  Quantitative PV-Haufen testing is a novel noninvasive approach to patient management for the diagnosis and prediction of PVN disease grades and monitoring of disease course during therapy.
authors.affiliation: 1 Division of Nephropathology, Department of Pathology and Laboratory Medicine, The University of North Carolina School of Medicine, Chapel Hill, NC. 2 Division of Nephrology and Hypertension, Department of Medicine, The University of North Carolina, Chapel Hill, NC. 3 Division of Abdominal Transplant Surgery, Department of Surgery, The University of North Carolina, Chapel Hill, NC.
authors.forename: Harsharan K
authors.initials: HK
authors.lastname: Singh
authors.forename: Howard
authors.initials: H
authors.lastname: Reisner
authors.forename: Vimal K
authors.initials: VK
authors.lastname: Derebail
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kozlowski
authors.forename: Volker
authors.initials: V
authors.lastname: Nickeleit
mesh_terms: D000952:Antigens, Polyomavirus Transforming / Q000737:chemistry; D001706:Biopsy; D004279:DNA, Viral / Q000652:urine*; D006085:Graft Survival; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis* / Q000821:virology*; D016133:Polymerase Chain Reaction; D011120:Polyomavirus / Q000502:physiology; D027601:Polyomavirus Infections / Q000175:diagnosis*; D015203:Reproducibility of Results; D014766:Viremia / Q000652:urine* / Q000821:virology*; D014779:Virus Replication
chemical_list: D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral