C1B score is associated with the final outcome of the patient and predicts patients’ evolution. (A-F) Correlation between (A,D) the percentage of CD14^dimCD16⁺ nonclassical monocytes of live CD45⁺ cells, (B,E) the nigericin-triggered fold of FAM-FLICA in CD66b⁺C16^dim cells compared with control, (C,F) the C1B score (defined as the percentage of CD14^dimCD16⁺ × fold FAM-FLICA in CD66b⁺CD16^dim cells) and the Spo₂/Fio₂ ratio at (A-C) day 1 and (D-F) day 3 of inclusion. The line represents the linear regression. Each dot represents a COVID-19 patient and the color its condition at the day of inclusion (blue, moderate; orange, severe; and red, critical). (G-I) Nigericin-triggered fold of FAM-FLICA in CD66b⁺C16^dim cells compared with control (H), percentage of CD14^dimCD16⁺ nonclassical monocytes of live CD45⁺ cells (G) and C1B score (I) as previously defined, observed in healthy donors or COVID-19 patients with favorable or unfavorable outcome. *P < .05; **P < .01; ***P < .001; ****P < .0001. r, Spearman coefficient.