Furthermore, our DEG analysis of scRNA-seq of bronchoalveolar fluid of patients with COVID-19 showed that expression of DPP9, NLRP1, and GSDMD, an effector protein for pyroptosis (Mathur et al., 2018), was significantly altered in Mo/Mφs of patients with severe COVID-19 compared to their moderate counterparts. Here, NLRP1 is linked to COVID-19.