CD1C and influenza: Analysis of CITE-seq-defined clusters (STAR Methods; Data S4) revealed increases in plasmablasts in severe disease; naive CD1c+ naive and cycling naive B cells were reduced in COVID-19, but overall, naive B cells were significantly more reduced in influenza than COVID-19 of comparable severity; and in mild hospitalized COVID-19, only the interferon-responsive naive B cell cluster showed an increase (Figures 4B and S6J).