ABSTRACT
Background: Viral entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) via the spike protein enables endocytosis into host cells using the ACE2 receptor and TMPRSS2. The frequent upper respiratory tract symptoms of COVID-19 and the localization of the virus to the nasopharynx, the most common site of swabbing, indicate that the sinonasal mucosa may play an important role in SARS-CoV2 infection and viral replication. Methods: This paper investigates the presence of ACE2 receptor and TMPRESS2 expression in the primary human nasal epithelial cells (HNECs) from the following: chronic rhinosinusitis without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP) and control (non-CRS) patients, and maps the expression changes when exposed to Th1, Th2, Th17-associated cytokines. Results: We found that ACE2 and TMPRSS2 expression was higher in control HNECs than CRSwNP HNECs, and that both ACE2 and TMPRSS2 were downregulated further by Th2 cytokines in CRSwNP HNECs. Conclusions: This indicates an immune dysregulated state of CRSwNP mucosa, which normally contributes to a chronic inflammatory state, and might support an altered susceptibility to SARS-CoV2 infection and transmission.