IL1RN and COVID-19: Intriguingly, we observed relatively higher levels of anti-inflammatory cytokines (IL1R2, IL1RN, and TGFB1) and lower levels of IL18 in BALF monocyte-macrophages from severe COVID-19 than mild cases, whereas classical pro-inflammatory cytokines (IL1A, IL1B, IL6, and TNF) were comparable between the two groups (Fig. 3f).