Increased systemic levels of inflammatory cytokines have been associated with the development of pathophysiologic events during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To further explore differences in the pattern and dynamics of plasma cytokines in individuals with coronavirus disease-19 (COVID-19), and the relationship with disease mortality, here we evaluated the plasma levels of proinflammatory and regulatory cytokines in Colombian patient survivors and nonsurvivors of SARS-CoV-2 infection. Individuals with confirmed COVID-19, with other respiratory diseases requiring hospitalization, and healthy controls, were included. Plasma levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon-γ, IL-10, soluble tumor necrosis factor receptor I (sTNFRI), and transforming growth factor-β1 were measured by a bead-based assay or enzyme-linked immunosorbent assay and clinical, laboratory, and tomographic parameters were registered during hospitalization. The levels of most of the evaluated cytokines were increased in COVID-19 individuals relative to healthy controls. The levels of IL-6, IL-10, and sTNFRI were directly associated with the development of respiratory failure, immune dysregulation, and coagulopathy, as well as with COVID-19 mortality. Particularly, the early, robust, and persistent increase of circulating IL-6 characterized COVID-19 nonsurvivors, while survivors were able to counteract the inflammatory cytokine response. In addition, IL-6 systemic levels positively correlated with the tomographic extension of lung damage in individuals with COVID-19. Thus, an exacerbated inflammatory cytokine response, particularly mediated by IL-6 added to the inefficiency of regulatory cytokines, distinguishes COVID-19-associated tissue disturbances, severity, and mortality in Colombian adults.
Keywords: COVID-19; SARS-CoV-2; interleukin-10; interleukin-6; total severity score.