Increased neutrophilic inflammation in CGD mice in response to zymosan was dependent on LTB4. (A-E) Wild-type and CGD mice were treated with zileuton or vehicle 30 minutes before and 4 hours after 20 μg zymosan challenge and examined at 8 or 24 hours, as indicated. (A) Representative immunohistochemical images of lung sections stained with MPO. Scale bars, 100 µm. (B,D) BAL leukocytes and PMNs (identified by Cytospin) and (C,E) lung PMNs (CD45⁺Ly6G⁺CD11b⁺ by flow cytometry) were analyzed 8 hours or 24 hours after challenge. (F) Mice were treated with zileuton or vehicle 8 hours after 20 µg zymosan challenge. BAL leukocytes and PMNs (identified by Cytospin) were analyzed 24 hours after challenge. n ≥ 3 per group from at least 2 separate experiments. Data are means ± standard error of the mean . (B-F) *P < .05, **P < .01, ***P < .001, ****P < .0001, by 1-way ANOVA.