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The polyomaviruses WUPyV and KIPyV: a retrospective quantitative analysis in patients undergoing hematopoietic stem cell transplantation

Nasim Motamedi*, Helga Mairhofer, Hans Nitschko, Gundula Jäger and Ulrich H Koszinowski

Author Affiliations

Max von Pettenkofer-Institute, Ludwig-Maximilians-University, Department of Virology, Pettenkoferstr. 9a, Munich D-80336, Germany

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Virology Journal 2012, 9:209  doi:10.1186/1743-422X-9-209

Published: 18 September 2012



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.


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).


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.

WU polyomavirus; KI polyomavirus; Gastrointestinal Tract; Respiratory system; Urine; Hematopoietic Stem Cell Transplantation; Immunocompromised Host; Viral Load