IL15 and COVID-19: First, we studied the circulating levels of IL-1α, IL-1β, IL-18, IL-15, IL-12p40, IL-12p70, IL-6, IL-27, IL-1Ra, IL-1RI, IL-1RII, IL-6R and sgp130, which are innate proinflammatory cytokines, and their receptors in survivors and non-survivors of severe COVID-19 and healthy controls.