title: Sustained BK viruria as an early marker for the development of BKV-associated nephropathy: analysis of 4128 urine and serum samples.
abstract: BACKGROUND
  BKV reactivation plays the causative role in the development of BKV-associated nephropathy (BKVAN). Because of the lack of effective therapy, early diagnosis of BKV reactivation is paramount for the prevention of BKVAN. Resting in uroepithelial cells, BKV is excreted first in urine before it can be detected in plasma. The present study analyzed predictive value of BK viruria for the development of BK viremia and its possible advantage for the early BKVAN prediction.
  
  
  METHODS
  Total of 4128 urine and serum samples obtained from renal transplant patients were analyzed for BKV positivity by real-time polymerase chain reaction in 433 patients in cross-sectional and in 233 patients in longitudinal manner, respectively. The prospective longitudinal analysis included seven measurements during the first posttransplant year.
  
  
  RESULTS
  A total of 7% and 19% patients were positive for BKV in serum and urine, respectively. Sustained BK viruria showed sensitivity of 100% and specificity of 94% for BK viremia and was associated with significantly higher level of BK load than the patients with transient viruria (P<0.01). Interestingly, BK viremia was preceded by BK viruria: the peak of viral load and number of positive patients appeared during the third and fifth posttransplant month for urine and serum, respectively. BKVAN diagnosed in 21.4% of patient with persistent BK viruria appeared 5 and 11 weeks after BKV reactivation in serum and urine, respectively, was detected.
  
  
  CONCLUSIONS
  Sustained BK viruria is a reliable marker allowing an early identification of patients at high risk of BKVAN development and therefore assure precocious therapeutic interventions.
authors: Department of Nephrology, Charité University Medicine Berlin, Campus Virchow Clinic, Berlin, Germany. nina.babel@charite.de
authors: Nina
authors: N
authors: Babel
authors: Juliane
authors: J
authors: Fendt
authors: Stoyan
authors: S
authors: Karaivanov
authors: Gantuja
authors: G
authors: Bold
authors: Steffen
authors: S
authors: Arnold
authors: Anett
authors: A
authors: Sefrin
authors: Evelyn
authors: E
authors: Lieske
authors: Martin
authors: M
authors: Hoffzimmer
authors: Mikalai
authors: M
authors: Dziubianau
authors: Nicole
authors: N
authors: Bethke
authors: Christian
authors: C
authors: Meisel
authors: Gerald
authors: G
authors: Grütz
authors: Petra
authors: P
authors: Reinke
mesh_terms: D000328:Adult; D001739:BK Virus / Q000235:genetics / Q000302:isolation & purification*; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000097:blood / Q000302:isolation & purification* / Q000652:urine; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000652:urine / Q000821:virology; D016030:Kidney Transplantation / Q000009:adverse effects*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D027601:Polyomavirus Infections / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000652:urine / Q000821:virology; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013997:Time Factors; D019562:Viral Load; D014766:Viremia / Q000175:diagnosis; D014775:Virus Activation
chemical_list: D004279:DNA, Viral