IL18 and acute respiratory distress syndrome: IL-18, a pro-inflammatory cytokine of the IL-1 family, is synthesized as an inactive precursor, processed to its active form by Casp1, and released.8 Based on prior reports of its role in multiple forms of lung injury including ARDS,9 SARS10, and influenza,11 IL-18 is expected to contribute to inflammatory lung injury caused by SARS-CoV-2 infection.