title: The polyomaviruses WUPyV and KIPyV: a retrospective quantitative analysis in patients undergoing hematopoietic stem cell transplantation.
abstract: BACKGROUND
  The polyomaviruses WUPyV and KIPyV have been detected in various sample types including feces indicating pathogenicity in the gastrointestinal (GI) system. However, quantitative viral load data from other simultaneously collected sample types are missing. As a consequence, primary replication in the GI system cannot be differentiated from swallowed virus from the respiratory tract. Here we present a retrospective quantitative longitudinal analysis in simultaneously harvested specimens from different organ sites of patients undergoing hematopoietic stem cell transplantation (HSCT). This allows the definition of sample types where deoxyribonucleic acid (DNA) detection can be expected and, as a consequence, the identification of their primary replication site.
  
  
  RESULTS
  Viral DNA loads from 37 patients undergoing HSCT were quantified in respiratory tract secretions (RTS), stool and urine samples as well as in leukocytes (n = 449). Leukocyte-associated virus could not be found. WUPyV was found in feces, RTS and urine samples of an infant, while KIPyV was repeatedly detected in RTS and stool samples of 4 adult patients.RTS and stool samples were matched to determine the viral load difference showing a mean difference of 2.3 log copies/ml (p < 0.001).
  
  
  CONCLUSIONS
  The data collected in this study suggest that virus detection in the GI tract results from swallowed virus from the respiratory tract (RT). We conclude that shedding from the RT should be ruled out before viral DNA detection in the feces can be correlated to GI symptoms.
authors.affiliation: Max von Pettenkofer-Institute, Ludwig-Maximilians-University, Department of Virology, Pettenkoferstr, 9a, Munich D-80336, Germany. motamedi@mvp.uni-muenchen.de
authors.forename: Nasim
authors.initials: N
authors.lastname: Motamedi
authors.forename: Helga
authors.initials: H
authors.lastname: Mairhofer
authors.forename: Hans
authors.initials: H
authors.lastname: Nitschko
authors.forename: Gundula
authors.initials: G
authors.lastname: Jäger
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: Koszinowski
mesh_terms: D000328:Adult; D005243:Feces / Q000821:virology; D005260:Female; D005767:Gastrointestinal Diseases / Q000821:virology; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D011120:Polyomavirus / Q000145:classification* / Q000302:isolation & purification*; D027601:Polyomavirus Infections / Q000821:virology*; D012141:Respiratory Tract Infections / Q000821:virology; D012189:Retrospective Studies; D013183:Sputum / Q000821:virology; D014556:Urine / Q000821:virology