Background: Interleukin 6 (IL-6) is a proinflammatory cytokine that is secreted by cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and it is widely recognized as a negative prognostic factor. The purpose of this study was to analyze the correlations between the olfactory scores determined by psychophysical tests and the serum levels of IL-6 in patients affected by coronavirus disease 2019 (COVID-19) Methods: Patients underwent psychophysical olfactory assessment with Connecticut Chemosensory Clinical Research Center test and IL-6 plasma level determination within 10 days of the clinical onset of COVID-19. Results: Seventy-four COVID-19 patients were included in this study. COVID-19 staged as mild in 34 patients, moderate in 26 and severe in 14 cases. There were no significant differences in olfactory scores across the different COVID-19 severity groups. In the patient series, the median plasma level of IL-6 was 7.7 pg/mL (IQR 3.7–18.8). The concentration of IL-6 was found to be significantly correlated with the severity of COVID-19 with a directly proportional relationship. The correlation between IL-6 plasma concentrations and olfactory scores was weak (rs = 0.182) and not significant (p = 0.12). Conclusions: In COVID-19 patients, psychophysical olfactory scores did not show significant correlations with the plasma levels of a well-recognized negative prognostic factor such as IL-6. This observation casts some shadows on the positive prognostic value of olfactory dysfunctions.
Correlations between IL-6 serum level and olfactory dysfunction severity in COVID-19 patients: a preliminary study / Vaira, L. A.; De Vito, A.; Deiana, G.; Pes, C.; Giovanditto, F.; Fiore, V.; Lechien, J. R.; Le Bon, S. -D.; Saussez, S.; Madeddu, G.; Babudieri, S.; Pazzola, A.; Bandiera, F.; Fois, A. G.; Piana, A. F.; Hopkins, C.; De Riu, G.. - In: EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY. - ISSN 0937-4477. - 279:2(2022), pp. 811-816. [10.1007/s00405-021-06868-5]