Cytokine profiles dynamics in COVID-19 patients: a longitudinal analysis of disease severity and outcomes

The outcome of the immune response depends on the content and magnitude of inflammatory mediators, the right time to start, and the duration of inflammatory responses. Patients with coronavirus disease 2019 (COVID-19) represent diverse disease severity. Understanding differences in immune responses in individuals with different disease severity levels can help elucidate disease mechanisms. Here, we serially analyzed the cytokine profiles of 809 patients with mild to critical COVID-19. The cytokine profile revealed an overall increase in IL-1β, IL-1Ra, TNF-α, IL-6, IL-2, IL-8, and IL-18 and impaired production of IFN-α and -β. Only an early rise in IL-1Ra, IL-6, and IL-2 levels was linked to worse disease outcomes. On the other hand, long-term rises in IL-1β, IL-1Ra, TNF-α, IL-6, IL-2, IL-8, and IL-18 levels were linked to worse disease outcomes. Principal component analysis identified a component, including IL-1β, TNF-α, IFN-α, and IL-12, that was associated with disease severity. Spearman analysis revealed that the correlation of IL-1β and IFN-α was entirely different between mild and critical patients. Therefore, the ratio of IL-1β to IFN-α seemed to be a suitable criterion for distinguishing critical patients from mild ones. The higher levels of the IL-1β to IFN-α ratio correlated with improved outcomes. These data point to an imbalance of IL-1β/IFNα, contributing to hyperinflammation in COVID-19.