Loss of S100A10 results in increased tissue fibrin deposition. Lung, liver, kidney, and spleen tissues from 6 WT and S100A10^−/− mice were collected, and the fibrin content of tissue lysates was determined by SDS-PAGE and Western blot analysis. A total of 10 ng of each tissue was loaded. Quantification of fibrin deposition was normalized to WT levels. Immunohistochemistry for fibrin was performed on perfused sections of formalin-fixed tissues. Sections were deparaffinized and incubated with antifibrin antibody followed by antirabbit HRP. Arrows indicate areas with fibrin deposition. Tissues observed were lung (A), liver (B), spleen (C), and kidney (D). Statistical analysis was performed with the use of Student t test, and the data are expressed as the mean (±) SEM of 6 independent experiments (**P < .01, ***P < .001). Sections were mounted by the use of Cytoseal 60 mounting media (Richard-Allen Scientific) and viewed with a 20×/0.5 NA objective lens. Images were captured by the Nikon Eclipse E600 microscope with a Nikon DXM1200F camera. Digital acquisition of the images was performed with ACT-1 Version 2.7 software (Nikon). Figures were generated with Adobe Photoshop CS3 Version 10 (Adobe Systems Incorporated).