Merkel cell polyomavirus DNA in tumor-free tonsillar tissues and upper respiratory tract samples: implications for respiratory transmission and latency.
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.
Kantola
Kalle
K
Department of Virology, Haartman Institute, University of Helsinki, P.O. Box 21, FIN-00014, Helsinki, Finland. kalle.kantola@helsinki.fi
Sadeghi
Mohammadreza
M
Lahtinen
Anne
A
Koskenvuo
Minna
M
Aaltonen
Leena-Maija
LM
Möttönen
Merja
M
Rahiala
Jaana
J
Saarinen-Pihkala
Ulla
U
Riikonen
Pekka
P
Jartti
Tuomas
T
Ruuskanen
Olli
O
Söderlund-Venermo
Maria
M
Hedman
Klaus
K
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
D004279:DNA, Viral