IL6 and COVID-19: Furthermore, the five cytokines and chemokines with up-regulated expression during the progression of COVID-19 were interleukin 6 (IL-6), interleukin 10 (IL-10), interferon gamma-induced protein 10 (IP-10), TNF-related apoptosis-inducing ligand (TRAIL), and stem cell growth factor beta (SCGF-β).