BSG and COVID-19: Despite their CD69 expression, activated eosinophils from severe COVID-19 patients displayed lower CD11a, CD66b, and CD147 expression compared to CD69+ eosinophils from the group with moderate disease (Fig. 4 G and H and SI Appendix, Fig. S4C), suggesting a partial functional impairment of eosinophils in the more severe COVID-19 stages.