Inflammatory markers and cytokines in moderate and critical cases of COVID-19

Background: Inflammatory responses have been suggested to be associated with coronavirus disease 2019 (COVID-19). This study investigated the inflammatory markers and cytokines in COVID-19 according to its severity. Methods: We enrolled 49 patients with COVID-19, who were classified as either moderate or critical cases. Serum or plasma interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) levels were measured. Results: Lactate dehydrogenase, ferritin, C-reactive protein, and procalcitonin levels were significantly higher in the critical group than in the moderate group (p < 0.001). IL-6 and TNF-α levels were significantly higher in the critical group, with elevated IL-6 levels from the first to third weeks after confirmed PCR (p < 0.05). Conclusions: Inflammatory markers and cytokines were increased in COVID-19 and closely related to the severity of the disease. We recommend early active monitoring of IL-6 levels along with inflammatory markers for severe COVID-19.