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

ABSTRACT 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. RESUMO OBJETIVO: COVID-19 e uma doenca sistemica que afeta multiplos orgaos, alem do sistema respiratorio. Embora os sintomas neurossensoriais, incluindo anosmia e ageusia, tenham sido frequentemente associados a formas mais leves de infeccao por SARS-CoV-2, o mecanismo patogenico e sua relacao com a imunomodulacao oromucosa permanecem pouco conhecidos. Portanto, o objetivo principal deste estudo piloto foi fornecer algumas evidencias sobre o padrao de citocinas na mucosa das vias aereas superiores em pacientes com COVID-19 com e sem anosmia e/ou ageusia. METODOS: Amostras de swabs nasofaringeos/orofaringeos foram obtidas de 12 pacientes com diagnostico de COVID-19. Os pacientes foram separados em dois grupos: com anosmia e/ou ageusia (A / A, n = 4) e um grupo controle com pacientes sem anosmia e/ou ageusia (NA / A, n = 8). A concentracao de citocinas na mucosa foi determinada por ELISA. RESULTADOS: Os niveis de IFN-γ, IL-6 e IL-10 na mucosa das vias aereas superiores foram semelhantes entre os grupos. Alem disso, nao foram encontradas diferencas significativas na proporcao de IFN-γ / IL-6, IFN-γ / IL-10 e IL-10/IL-6 entre os dois grupos. No entanto, usando o coeficiente de correlacao de Pearson encontramos correlacoes positivas significativas entre IL-6 e IFN-γ, IL-10 e IFN-γ, e tambem IL-10 e IL-6 no grupo controle (NA / A), enquanto a correlacao negativa significativa entre IL-10 e IFN-γ foi encontrada no grupo A / A. CONCLUSAO: Nossos resultados sugerem que pacientes com formas leves de COVID-19, apresentando anosmia e/ou ageusia, apresentam alteracao da resposta imune da mucosa das vias aereas superiores. DESCRITORES: SARS-CoV-2. Sintomas neurossensoriais. IL-6. IL-10. IFN-gama.