CASP1 and COVID-19: However, IL-1β and IL-18, together with the caspase-1 substrate gasdermin D (GSDMD) and lactate dehydrogenase (LDH, released during pyroptosis), have been associated with severe courses of COVID-19.1,5 The current study identifies infected monocytes as the likely source of these inflammatory drivers of disease and suggests that enhanced inflammasome activation contributes to excessive inflammation and severe COVID-19.