Journal Article

Longitudinal Analysis of Inflammatory Response to SARS-CoV-2 in the Upper Respiratory Tract Reveals an Association with Viral Load, Independent of Symptoms

Kaiser, Laurent, Pigny Fiona, Lemeille Sylvain, Vono, Maria, Didierlaurent, Arnaud M, Huttner, Angela, Blanchard-Rohner Géraldine, Eberhardt, Christiane S, Meyer, Benjamin, Martinez-Murillo, Paola, Von Dach Elodie, Diem-Lan, Vu, Eckerle Isabella, Siegrist Claire-Anne

2021

Overview

BackgroundSARS-CoV-2 infection leads to high viral loads in the upper respiratory tract that may be determinant in virus dissemination. The extent of intranasal antiviral response in relation to symptoms is unknown. Understanding how local innate responses control virus is key in the development of therapeutic approaches.MethodsSARS-CoV-2-infected patients were enrolled in an observational study conducted at the Geneva University Hospitals, Switzerland, investigating virological and immunological characteristics. Nasal wash and serum specimens from a subset of patients were collected to measure viral load, IgA specific for the S1 domain of the spike protein, and a cytokine panel at different time points after infection; cytokine levels were analyzed in relation to symptoms.ResultsSamples from 13 SARS-CoV-2-infected patients and six controls were analyzed. We found an increase in CXCL10 and IL-6, whose levels remained elevated for up to 3 weeks after symptom onset. SARS-CoV-2 infection also induced CCL2 and GM-CSF, suggesting local recruitment and activation of myeloid cells. Local cytokine levels correlated with viral load but not with serum cytokine levels, nor with specific symptoms, including anosmia. Some patients had S1-specific IgA in the nasal cavity while almost none had IgG.ConclusionThe nasal epithelium is an active site of cytokine response against SARS-CoV-2 that can last more than 2 weeks; in this mild COVID-19 cohort, anosmia was not associated with increases in any locally produced cytokines.

• Publisher: Springer Nature B.V
• Subject: Anosmia / Antiviral drugs / Cell activation / COVID-19 / CXCL10 protein / Cytokines / Epithelium / Granulocyte-macrophage colony-stimulating factor / Immunoglobulin A / Immunoglobulin G / Infections / Inflammation / Interleukin 6 / Monocyte chemoattractant protein 1 / Myeloid cells / Nose / Olfaction disorders / Patients / Respiratory tract / Severe acute respiratory syndrome coronavirus 2 / Spike protein