title: WU and KI polyomavirus infections in pediatric hematology/oncology patients with acute respiratory tract illness.
abstract: BACKGROUND
  WU and KI polyomaviruses (PyV) were discovered in 2007 in respiratory tract samples in adults and children. Other polyomaviruses (BKPyV and JCPyV) have been associated with illness in immunocompromised patients, and some studies suggest a higher prevalence of WUPyV and KIPyV in this population.
  
  
  OBJECTIVE
  To determine whether a higher prevalence or viral load for WUPyV and KIPyV exists in immunocompromised children compared with immunocompetent children.
  
  
  METHODS
  We measured the prevalence and viral load of WU and KI PyV by quantitative real-time PCR of viral DNA in respiratory tract specimens from pediatric hematology/oncology patients and immunocompetent controls with acute respiratory illnesses.
  
  
  RESULTS
  The prevalence of WUPyV in the immunocompromised population was 5/161 (3%) versus 14/295 (5%) in the control population (P=0.5), and 9/161 (5.6%) versus 7/295 (2.3%) respectively for KIPyV (P=0.13). The mean viral load (in copies per cell or mL of sample) for KIPyV, was higher in the immunocompromised group compared to the control group (P=0.019), but was not statistically different for WUPyV. A higher prevalence was seen in the hematopoietic stem cell transplant recipients compared with other immunocompromised patients (6/26 versus 3/43, P=0.054). Viral persistence was demonstrated only in 1/25 (4%) of sequential samples for KIPyV, and no persistence was seen for WUPyV.
  
  
  CONCLUSIONS
  A higher prevalence of WUPyV or KIPyV in the immunocompromised population compared with the immunocompetent group was not demonstrated. Higher viral loads for KIPyV in the immunocompromised group may suggest an increased pathogenic potential in this population.
authors.affiliation: Department of Pediatrics, B158 The Children's Hospital and University of Colorado School of Medicine, Aurora, CO 80045, USA. rao.suchitra@tchden.org
authors.forename: Suchitra
authors.initials: S
authors.lastname: Rao
authors.forename: Robert L
authors.initials: RL
authors.lastname: Garcea
authors.forename: Christine C
authors.initials: CC
authors.lastname: Robinson
authors.forename: Eric A F
authors.initials: EA
authors.lastname: Simões
mesh_terms: D015331:Cohort Studies; D060085:Coinfection / Q000453:epidemiology / Q000821:virology*; D004279:DNA, Viral / Q000235:genetics; D006402:Hematologic Diseases / Q000150:complications* / Q000453:epidemiology; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D016867:Immunocompromised Host; D009369:Neoplasms / Q000150:complications* / Q000453:epidemiology; D011120:Polyomavirus / Q000302:isolation & purification*; D027601:Polyomavirus Infections / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D012141:Respiratory Tract Infections / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D012189:Retrospective Studies; D019562:Viral Load
chemical_list: D004279:DNA, Viral