title: Relationship of pretransplantation polyoma BK virus serologic findings and BK viral reactivation after hematopoietic stem cell transplantation.
abstract: BACKGROUND
  Reactivation of polyoma BK virus (BKV) infection is consistently associated with hemorrhagic cystitis in persons who undergo hematopoietic stem cell transplantation (HSCT). In this study, we examined the relationship of reactivation of BKV infection with pre-HSCT serologic findings of BKV antibody.
  
  
  METHODS
  Serial urine samples (n=1118) obtained from 140 HSCT recipients were prospectively obtained, and BKV loads were quantified by quantitative polymerase chain reaction. Pre-HSCT anti-BKV immunoglobulin G (IgG) levels were determined by indirect immunofluorescence.
  
  
  RESULTS
  In 68 patients, there was significant peaking (i.e., > or = 3-log increase) in the urine BKV load (median peak, 1.7x10(9) copies/mL; range, 1.1x10(4) to 3.2x10(14) copies/mL) occurring at a median time of 24.5 days (range, 7-49 days). In 72 patients, low-level BKV viruria occurred without peaking (median BKV load, 10 copies/mL; range, 9.9x10(3) to 1.2x10(10) copies/mL) at a median time of 24.5 days (range, 7-49 days). Pre-HSCT anti-BKV IgG was positively related to elevated urine BKV load during HSCT (P<.001). Binary logistic regression revealed that pre-HSCT anti-BKV IgG level was the only statistically significant factor (P=.009) to be associated with a > or = 3-log increase in the peak urine BKV load (positive and negative predictive values, 69% and 68%, respectively). Nine patients developed hemorrhagic cystitis at a median of 56 days (range, 29-160); 7 of these patients were evaluable and were found to have a > or = 3-log increase in the peak BKV load. In binary logistic regression, peaking of the urine BKV load (P=.026) and graft-versus-host disease (P=.033) were found to be statistically significant risks for hemorrhagic cystitis.
  
  
  CONCLUSIONS
  The identification of the serologic status of BKV as a significant risk factor for BKV viruria suggests that it should be included as an integral part of the pre-HSCT evaluation.
authors.affiliation: Department of Medicine, University of Hong Kong, China.
authors.forename: Anders S Y
authors.initials: AS
authors.lastname: Wong
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Chan
authors.forename: Vincent C C
authors.initials: VC
authors.lastname: Cheng
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
authors.forename: Yok-Lam
authors.initials: YL
authors.lastname: Kwong
authors.forename: Anskar Y H
authors.initials: AY
authors.lastname: Leung
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001739:BK Virus / Q000302:isolation & purification*; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005500:Follow-Up Studies; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000150:complications / Q000175:diagnosis*; D011300:Preoperative Care; D011336:Probability; D011446:Prospective Studies; D012008:Recurrence; D018570:Risk Assessment; D012698:Serologic Tests; D017678:Sex Distribution; D014181:Transplantation Immunology / Q000502:physiology; D016482:Urinalysis; D019562:Viral Load
chemical_list: D004279:DNA, Viral