RIPK1 and COVID-19: We found a strikingly enriched presence of activated RIPK1 in the ciliated epithelial cells in the airways of severe COVID-19 patients which corresponds to elevated levels of proinflammatory cytokines and factors in the BALF, lung and PBMCs in patients compared to that of control individuals (Fig. 1b and Supplementary information Figs. S1b and S2b).