Imaging flow cytometry analysis of mouse BM EBIs. (A) Cell clusters with more than 250 (Area_BF) were gated (a) as potential EBIs; (b) plot of F4/80 and Ter119 of the gated cell clusters. (B) Top: a representative EBI structure showing F4/80⁺Epor-eGFP⁺ macrophage was surrounded by multiple Ter119⁺ erythroid cells; bottom: a representative image showing the F4/80⁺Epor-eGFP⁻ macrophage was surrounded by 1 Ter119⁺ erythroid cell. (C) Quantitative analyses revealing >90% EBIs were formed by the F4/80⁺Epor-eGFP⁺ macrophages. (D) Quantitative analyses showing percentages of EBIs with 3, 4, and 5 or more erythroid cells. (C-D) Quantitative analyses were performed using 2000 EBIs from 8 independent experiments.