Study flow chart and the number of eosinophils and their progenitors after endotoxin challenge. (A) Study design. Seven healthy volunteers underwent a baseline bone marrow aspiration and vena puncture (blue). Seven volunteers were challenged with an intravenous dose of 2 ng/kg lipopolysaccharide (LPS) at day 7 and a second bone marrow aspiration and blood withdrawal 4 h later (red). Finally, 6 volunteers underwent a final bone marrow aspiration and blood withdrawal at day 14 (orange). (B) Number of eosinophils in the bone marrow and blood, and their progenitors (from eosinophil promyelocyte stage and further) in the bone marrow are depicted as a percentage of total nucleated cells. (C) Number of EoPs (CD34+ and IL-5Rα+ cells) in the bone marrow is depicted as a percentage of total nucleated cells or (D) as a percentage of CD34+ cells. (E) Number of CD34+ cells is depicted as a percentage of total nucleated cells. Results are plotted as median ± IQR (interquartile range). A Wilcoxon matched-pairs signed rank test was performed. NS, not significant. *P ≤ 0.05; **P ≤ 0.01; ****P ≤ 0.0001