For this, we have measured the expression of the different players implicated in the NLRP3 inflammasome pathway including NLRP3, CASP-1, ASC, IL-1β and IL-18 in whole blood of severe COVID-19 patients treated or not with 50,000 IU cholecalciferol once per week for 2–3 weeks during their stay at ICU. The gene discussed is PYCARD; the disease is COVID-19.