Anosmia and ageusia in covid-19 patients: the cytokines profile in upper airways

OBJECTIVE: COVID-19 is a systemic disease affecting multiple organs, beyond the respiratory system. Although sensorineural symptoms, including anosmia and ageusia, have been frequently associated with milder forms of SARS-CoV-2 infection, the pathogenic mechanism and its relation with oromucosal immunomodulation remains poorly understood. Therefore, the main objective of this pilot study was to provide some pieces of evidence concerning the cytokines pattern in the mucosa of the upper airways in COVID-19 patients with and without anosmia and/or ageusia. METHODS: Samples of nasopharyngeal/oropharyngeal swabs were obtained from 12 patients diagnosed with COVID-19. The patients were separated into two groups: with anosmia and/or ageusia (A/A,n=4), and a control group with patients without anosmia and/or ageusia (NA/A,n=8). RESULTS: Mucosal cytokines concentration was determined by ELISA. Levels of IFN-γ, IL-6, and IL-10 in the mucosa of the upper airways were similar between the groups. In addition, no significant differences were found in the ratio of IFN-γ/IL-6, IFN-γ/IL-10, and IL-10/IL-6 between the two groups. However, using Pearson's correlation coefficient we found a significant positive correlations between IL-6 and IFN-γ, IL-10 and IFN-γ, and also IL-10 and IL-6 in the control group (NA/A), whereas a significant negative correlation between IL-10 and IFN-γ was found in A/A group. CONCLUSION: Our results suggest that patients with mild forms of COVID-19, presenting anosmia and/or ageusia, have an altered mucosal immune response in the upper airways. DESCRIPTORS: SARS-CoV-2, Sensorineural symptoms, IL-6, IL-10, IFN-gamma.