Merkel cell polyomavirus DNA in immunocompetent and immunocompromised patients with respiratory disease

Abstract

Merkel cell polyomavirus (MCPyV) was identified originally in association with a rare but aggressive skin cancer, Merkel cell carcinoma. The virus has since been found in the respiratory tract of some patients with respiratory disease. However, the role of MCPyV in the causation of respiratory disease has not been established. To determine the prevalence of MCPyV in 305 respiratory samples from immunocompetent and immunocompromised patients and evaluate their contribution to respiratory diseases, specimens were screened for MCPyV using single, multiplex, or real-time PCR; co-infection with other viruses was examined. Of the 305 samples tested, 10 (3.27%) were positive for MCPyV. The virus was found in two groups of patients: in 6 (2%) nasopharyngeal aspirate samples from children aged 26 days to 7 months who were immunocompetent; and in 4 (1.3%) of nasopharyngeal aspirate samples taken from patients aged 41 to 69 years who were severely immunosuppressed from leukemia or transplant therapy. Both groups had upper or lower respiratory tract infection. Co-infections with other viruses were found in 30% of the MCPyV positive samples. The data present a pattern of infection similar to that seen with the polyomaviruses JC and BK in which the virus is acquired during childhood, probably by the respiratory route. The viruses then establish latency and become reactivated in the event of immunosuppression.

Detection of Merkel Cell Polyomavirus in Respiratory Tract Specimens

“…It is possible that this could result in a higher sensitivity of PCR and accordingly a higher frequency of virus detection. Using primers targeting the large T-antigen gene, Abedi Kiasari et al [15] determined their PCR sensitivity to be 1,000 copies/mL. This is more than 5 times less sensitive than our VP1 PCR (<200 copies/ mL).…”

“…In this group, the MCPyV prevalence rate reached 8.2%, which is higher than the results of previous studies in other countries. The frequency of detection of MCPyV DNA in NPS obtained from patients with respiratory symptoms ranges from 1.3% (Australia) to 4.2% (Sweden) [12][13][14][15]22] . It has been previously shown that the variation in MCPyV prevalence may be partially explained by methodological differences.…”

“…However, the route of MCPyV transmission and the sites of the initial and latent infections have not yet been identified. Many studies have demonstrated the existence of MCPyV DNA in diverse specimens, including respiratory tract specimens [12][13][14][15] . MCPyV DNA has been detected in a variety of non-MCC cancers, including chronic lymphocytic leukemia, malignant tonsillar tissues, cervical carcinomas, nonmelanoma skin cancers, and lung cancer [16][17][18][19][20][21] .…”

“…It has been shown that MCPyV can infect the upper and lower respiratory tract [12][13][14][15]22] . Sequence data have indicated that MCPyV found in respiratory secretions is similar to the virus identified in MCC [23] .…”

Characterising the pathogenesis and biology of newly described human polyomaviruses

“…[254]- [256] A high prevalence of MCPyV was found in respiratory secretions with and without clinical symptoms suggesting it may, like other human polyomaviruses, have a respiratory route of infection. [257]- [259] Confounding studies to date are the high levels of MCPyV DNA in the environment and from skin swabs. [159], [260] MCPyV DNA is detected in 75% of environmental swabs, and can still be detected after DNAse digestion, suggesting that like HPyV6,7 & 9, MCPyV is shed as whole virions from healthy human skin.…”