Neutrophil transmigration is delayed in treml1^−/−mice. (A) Examples of gross BALF obtained from treml1^−/− and WT mice after 24 hours of intranasal PBS or LPS treatment. The reddish BALF in treml1^−/− is consistent with increased bleeding. (B) Hematoxylin and eosin histological analysis of the lungs of the WT and treml1^−/− mice treated with either PBS or LPS. (C) Flow cytometric based quantification of bleeding in BALF from treml1^−/− and WT mice after 24 hours of intranasal PBS or LPS treatment. As shown, BALF from treml1^−/− mice had significantly more red blood cells (RBCs) compared with WT (n = 5-7 per group; *P ≤ .05, 1-way analysis of variance [ANOVA]). (D-E) WT and Treml1^−/− mice were given LPS or PBS control intranasally. The number of neutrophils in BALF was examined 12 hours (D) and 24 hours (E) after intranasal LPS or PBS treatment (n = 6 mice per group; *P ≤ .05, **P ≤ .001; 1-way ANOVA). All cytometric quantifications were done using BD Accuri C6 software (BD Biosciences).