Avaliação in vitro de biomarcadores inflamatórios específicos para SARS-CoV-2 em sangue total de pacientes recuperados e com COVID-19 longa

Abstract

Cytokines induced by SARS-CoV-2 infection play a crucial role in the pathophysiology of COVID-19 and hyperinflammatory responses have been associated with poor clinical outcomes, with progression to severe conditions or long-term subacute complications named as post-COVID or long COVID. In this cross-sectional study, we aimed to evaluate a set of antigen-specific inflammatory cytokines in blood from recovered COVID-19 individuals or who suffered a post-acute phase of SARS-CoV-2 infection compared to healthy individuals with no history of COVID-19 exposition or infection. Interferon-gamma (IFN-γ), IFN-γ-induced protein 10 (IP-10), tumor necrosis factor (TNF), IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, and IL-17A were quantified by multiplex cytometric bead assay (CBA) and enzyme-linked immunosorbent assay (ELISA) after stimulation of whole blood with recombinant Spike protein from SARS-CoV-2. Additionally, all participants have evaluated for anti-(S) protein-specific IgG antibodies. Clinical specimens were collected approximately within two and half months of COVID-19 diagnosis. A total of 47 individuals were enrolled in the study, the median age of 43 years (IQR=14.5), grouped into healthy individuals with no history of infection or exposure to SARS-CoV-2 (unexposed group; N=21); and patients from the Health Complex of the Rio de Janeiro State University (UERJ), who were SARS-CoV-2 positive by RT-PCR (COVID-19 group) – categorized as recovered COVID (N=11) or long-COVID (N=15). All COVID-19 patients presented at least one signal or symptom during the first two weeks of infection. Six patients were hospitalized and required invasive mechanical ventilation. Our results showed that COVID-19 patients had significantly higher levels of IFN-γ, TNF, IL-1β, IL-2, IL-6, IL-8, and IP-10 compared to the unexposed group. The long COVID group has presented significantly high levels of IL-1β and IL-6 compared to unexposed individuals, but not from recovered COVID. A principal-component analysis demonstrated 84.3% of the total variance of inflammatory-SARS-CoV-2 response in the first two components, and it was possible to stratify IL-6, TNF, IL-1β, IL-10, and IL-2 as the top-five cytokines which are candidates to discriminate COVID-19 group (including long COVID subgroup) and healthy unexposed individuals. Our study showed differential S-protein-specific biomarkers of SARS-CoV-2 in individuals affected by COVID-19, bringing a better understanding of the inflammatory state and determination of exposure to SARS-CoV-2