PLoS ONE (Jan 2022)

Evidence of SARS-CoV-2 in nasal brushings and olfactory mucosa biopsies of COVID-19 patients

  • Carlotta Pipolo,
  • Daniele Bottai,
  • Emanuela Fuccillo,
  • Eleonora Aronica,
  • Fabio Bruschi,
  • Antonio Mario Bulfamante,
  • Luca Castellani,
  • Maria Paola Canevini,
  • Davide Chiumello,
  • Sergio Ferrari,
  • Carla Martinelli,
  • Stefano Muttini,
  • Alberto Priori,
  • Alberto Maria Saibene,
  • Chiara Spoldi,
  • Delfina Tosi,
  • Gianluigi Zanusso,
  • Gaetano Pietro Bulfamante,
  • Giovanni Felisati

Journal volume & issue
Vol. 17, no. 4

Abstract

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The aim of the present study is to detect the presence of SARS-CoV-2 of patients affected by COVID-19 in olfactory mucosa (OM), sampled with nasal brushing (NB) and biopsy, and to assess whether a non-invasive procedure, such as NB, might be used as a large-scale procedure for demonstrating SARS-CoV-2 presence in olfactory neuroepithelium. Nasal brushings obtained from all the COVID-19 patients resulted positive to SARS-CoV-2 immunocytochemistry while controls were negative. Double immunofluorescence showed that SARS-CoV-2 positive cells included supporting cells as well as olfactory neurons and basal cells. OM biopsies showed an uneven distribution of SARS-CoV-2 positivity along the olfactory neuroepithelium, while OM from controls were negative. SARS-CoV-2 was distinctively found in sustentacular cells, olfactory neurons, and basal cells, supporting what was observed in NB. Ultrastructural analysis of OM biopsies showed SARS-CoV-2 viral particles in the cytoplasm of sustentacular cells. This study shows the presence of SARS-CoV-2 at the level of the olfactory neuroepithelium in patients affected by COVID-19. For the first time, we used NB as a rapid non-invasive tool for assessing a potential neuroinvasion by SARS-CoV-2 infection.