What is it about?

Objective: EBV detection using nasopharyngeal swabs has been suggested as a potential screening test that could improve the specificity of current EBV-based serological assays. However, application requires insertion of the swab deep into the nasopharynx, a procedure not amenable to non-clinic screening. We reasoned that swabbing the more easily accessible nasal cavity might provide an appealing alternative for NPC detection. Methods: Patients >18 years of age diagnosed with histologically confirmed NPC were recruited from the Otolaryngology Department at the National Taiwan University Hospital. ENT clinicians collected both nasal and nasopharyngeal swabs. EBV DNA and cellular beta-globulin DNA were quantified using quantitative PCR targeting a highly-conserved region of the BKRF1 gene. Results: EBV DNA was detectable (non-zero) in all nasopharyngeal swabs and above the positivity threshold of 1,666 EBV copies in 30 patients. EBV DNA was detectable in 50% of nasal swabs and above the positivity threshold in 4 patients. Average EBV DNA levels were >3-fold higher (P<0.001) in nasopharyngeal compared to nasal swabs. Among the 17 NPC patients with detectable EBV DNA in both swab types, we observed correlation (P<0.01) between EBV DNA measurements. Conclusion: Our data represent the first evaluation of EBV DNA collected from nasal swabs. Given current EBV DNA amplification techniques, nasopharyngeal swabs remain more sensitive than nasal swabs for NPC detection.

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Why is it important?

The study indicates that , -in order to accurately and sensitively detect the presence "in situ" of nasopharyngeal carcinoma via measuring EBV-DNA load-, proper deep nasopharyngeal swabbing/brushing is important and superior to nasal brushing.

Perspectives

This study highlights and supports earlier demonstrations indicating that nasopharyngeal brushing combined woth EBV-DNA load measurement (by PCR) is an excellent minimal invasive procedure to detect the presence of nasopharyngeal carcinoma (NPC) "in situ", and may replace the painful biopsy. This approach may be useful for early-stage NPC diagnosis in "high risk" persons, presenting to the clinic with suspicious non-specific symptoms of NPC, for screening "high risk" family members of NPC patients and for confirmation of individuals with elevated EBV-IgA serology in screening programs.

prof.dr. (emeritus professor) Jaap Michiel Middeldorp
VU University medical center and Cancer Center Amsterdam, dept. Pathology

Read the Original

This page is a summary of: Evaluation of nasal and nasopharyngeal swab collection for the detection of Epstein-Barr virus in nasopharyngeal carcinoma, Journal of Medical Virology, September 2017, Wiley,
DOI: 10.1002/jmv.24918.
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