Liquid-based cytological and immunohistochemical study of nasopharyngeal swab from persons under investigation for SARS-CoV-2 infection

Abstract

Introduction: We describe cytologic and immunohistologic findings in virus transport medium on cases under investigation of SARS-CoV-2 infection.

Methods: Cytologic findings in cases under investigation of SARS-CoV-2 infection from one hundred consecutive nasopharyngeal swab were reviewed. Immunohistochemistry and SARSCoV-2 RT-PCR determination were performed to detect virus.

Results: No viral inclusions were noted in squamous cells obtained from virus transport medium. Immunohistochemical study with monoclonal antibody against SARS-CoV-2 viral nucleoprotein showed positivity in squamous cells. No positivity was present in others cellular components.

Conclusions: SARS-CoV-2 predominantly localizes squamous cells in cytology samples of patients with RT-PCR positive determination of SARSCoV-2. The results of the current study support the notion that the nasopharyngeal region is the anatomical station that SARS-CoV-2 infects first, and the infection can lead to the migration of the virus into the lower airways.

Keywords: COVID-19; RT-PCR; SARS-CoV-2; cytology; immunohistochemical; liquid-based; nasopharynx; swab; viral transport medium.