Figure 1. The identification of a CD16 intermediate low-density neutrophil population in COVID-19 patients.

(A) The averaged percentage of CD16-negative (CD16^Neg), CD16 intermediate (CD16^Int), and CD16 high (CD16^hi) neutrophils from serially drawn whole blood samples among healthy donors (HD, n = 6), comorbid control patients (Cm Ctrl, n = 9), and moderate (n = 24) and severe (n = 12) COVID-19 patients. Cells were gated on the CD45⁺CD66b⁺ population. Summarized data and representative dot plots are shown. (B) Cluster maps for moderate and severe COVID-19 patients compared with HD and Cm Ctrl. The data were generated from CyTOF-based analysis of CD45⁺ PBMCs isolated from peripheral blood. (C) Representative dot plots (left) and summarized data (right) showing the overall percentage of CD66b⁺ neutrophils (gated on viable, CD45⁺) and the CD16^Int subset as found in Ficoll-isolated PBMCs analyzed using CyTOF mass cytometry in HD, Cm Ctrl, and moderate and severe COVID-19 patients. (D) Representative viSNE cluster plots show the CD66b (left) and CD16 (right) expression within the CD45⁺ PBMC populations in Cm Ctrl and patients with moderate and severe COVID-19. Red circles indicate the location of the neutrophil population; blue circles indicate the CD16^Int neutrophil population. Data are presented as mean ± SD. P values were determined using 1-way ANOVA with multiple comparisons. **P < 0.01, ***P < 0.001, ****P < 0.0001.