Excessive neutrophil adhesion impairs histamine-induced vascular permeability in EHCgp130^−/−mice. (A) Extravasation of Evan’s blue dye (injected intravenously) into the skin of WT or EHCgp130^−/− mice was measured 30 minutes after intradermal injection of saline or histamine. As indicated, anti–P-selectin mAb was injected intravenously before Evan’s blue dye was injected. (B) Whole-mount confocal images of skin from LysMCre⁺ or EHCgp130^−/−/LysMCre⁺ mice. The mice were injected intradermally with saline or histamine. After 20 minutes, they were injected intravenously with biotin-conjugated anti-CD31 mAb. After another 10 minutes, they were sacrificed. The skin was rapidly excised, fixed, permeabilized, and stained with secondary Alexa 546–conjugated streptavidin. GFP-positive neurophils show as green and CD31-positive endothelial cells show as red. As indicated, anti–P-selectin mAb was injected intravenously before the intradermal injection. The bar represents 50 µm. The data in (A) represent the mean ± SEM from 5 mice in each group. The data in (B) are representative of 3 experiments. *P < .05.