Dysregulated and excessive inflammatory responses, characterizedby the hyperproduction of several pro-inflammatory cytokines and theinitiation of different inflammatory signaling cascades, are hallmarksof ARDS and multiorgan failure.10 Alongwith cytokine and chemokine increases, the S-protein–LPS-inducedmouse model, with its reductionist approach, also captures featuresof the complex lung pathology seen in patients with severe COVID-19in the acute phase. Here, PROS1 is linked to acute respiratory distress syndrome.