IL6 and COVID-19: Severe COVID-19 are characteristic by uncontrolled inflammatory responses and cytokine storm-like syndromes, so abnormally increased inflammatory biomarkers and cytokines (e.g., procalcitonin (PCT), C-reactive protein (CRP), interleukin-6 (IL-6), IL-1β, IL-1RA, IL-17A, and tumor necrosis factor-α (TNF-α)) also were observed in COVID-19 patients without bacterial infection [10–13].