IL21 and COVID-19: First, we studied the profile of different soluble pro-inflammatory cytokines (GM-CSF, TNF-α, IFN-γ, IL-1β, IL-2, IL-6, IL-7, IL-10, IL-17A, IL-21) and chemokines mediating monocyte and neutrophil recruitment (IL8, CCL3), whose exacerbated production is associated with severe COVID-19 [23,26,31,32].