title: Merkel cell polyomavirus DNA in tumor-free tonsillar tissues and upper respiratory tract samples: implications for respiratory transmission and latency.
abstract: BACKGROUND
  Merkel cell polyomavirus (MCPyV) was discovered recently. It is considered a potential causative agent of Merkel cell carcinoma, a life-threatening skin cancer.
  
  
  OBJECTIVE
  To study the prevalence of MCPyV in a large number of clinical samples of various types. Most of the samples were examined also for the other newly found polyomaviruses KI (KIPyV) and WU (WUPyV).
  
  
  METHODS
  Altogether 1390 samples from immunocompetent or immunocompromised patients, including (i) tonsillar tissues and sera from tonsillectomy patients; (ii) nasopharyngeal aspirates (NPAs) and sera from wheezing children and (iii) nasal swabs, sera and stools from febrile leukemic children were studied for MCPyV. The tonsils, nasal swabs and stools were also studied for KIPyV and WUPyV.
  
  
  RESULTS
  MCPyV DNA was detected in 14 samples altogether; 8 of 229 (3.5%) tonsillar tissues, 3 of 140 (2.1%) NPAs, 2 of 106 (1.9%) nasal swabs and 1 of 840 (0.1%) sera. WUPyV and KIPyV were detected in 5 (2.2%) and 0 tonsils, 1 (0.9%) and 4 (3.8%) nasal swabs and 0 and 2 (2.7%) fecal samples, respectively. The patients carrying in tonsils MCPyV were of significantly higher age (median 42years) than those carrying WUPyV (4years, p<0.001).
  
  
  CONCLUSIONS
  MCPyV DNA occurs in tonsils more frequently in adults than in children. By contrast, WUPyV DNA is found preferentially in children. MCPyV occurs also in nasal swabs and NPAs, in a frequency similar to that of KIPyV and WUPyV. The tonsil may be an initial site of WUPyV infection and a site of MCPyV persistence.
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, P.O. Box 21, FIN-00014, Helsinki, Finland. kalle.kantola@helsinki.fi
authors.forename: Kalle
authors.initials: K
authors.lastname: Kantola
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Sadeghi
authors.forename: Anne
authors.initials: A
authors.lastname: Lahtinen
authors.forename: Minna
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Leena-Maija
authors.initials: LM
authors.lastname: Aaltonen
authors.forename: Merja
authors.initials: M
authors.lastname: Möttönen
authors.forename: Jaana
authors.initials: J
authors.lastname: Rahiala
authors.forename: Ulla
authors.initials: U
authors.lastname: Saarinen-Pihkala
authors.forename: Pekka
authors.initials: P
authors.lastname: Riikonen
authors.forename: Tuomas
authors.initials: T
authors.lastname: Jartti
authors.forename: Olli
authors.initials: O
authors.lastname: Ruuskanen
authors.forename: Maria
authors.initials: M
authors.lastname: Söderlund-Venermo
authors.forename: Klaus
authors.initials: K
authors.lastname: Hedman
mesh_terms: D000234:Adenoids / Q000821:virology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002353:Carrier State / Q000453:epidemiology* / Q000821:virology; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000821:virology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018862:Merkel Cells / Q000821:virology*; D008875:Middle Aged; D011120:Polyomavirus / Q000235:genetics / Q000302:isolation & purification*; D027601:Polyomavirus Infections / Q000453:epidemiology* / Q000821:virology; D015995:Prevalence; D012137:Respiratory System / Q000821:virology*; D044967:Serum / Q000821:virology; D055815:Young Adult
chemical_list: D004279:DNA, Viral