['Particulate air pollution is associated with cardiovascular diseases and myocardial infarction (MI).', 'We investigated the relationship between airway inflammation and thrombosis 24 hours after intratracheal (IT) instillation of diesel exhaust particles (DEP; 50 microg/hamster). Mild thrombosis was induced in the femoral vein by endothelial injury, and the consequences of airway inflammation on thrombogenicity were studied via online video microscopy. Lung inflammation and histamine analysis in bronchoalveolar lavage (BAL) and plasma were performed after pretreatment with dexamethasone (DEX) or sodium cromoglycate (SC). DEP induced airway inflammation and histamine release in BAL and in plasma, and increased thrombosis, without elevating plasma von Willebrand factor (vWF) levels. The IT instillation of 400-nm positively charged polystyrene particles (500 microg/hamster), serving as particles that do not penetrate into the circulation, equally produced airway inflammation, histamine release, and enhanced thrombosis. Histamine in plasma resulted from basophil activation. Intraperitoneal (IP) pretreatment with DEX (5 mg/kg) abolished the DEP-induced histamine increase in BAL and plasma and abrogated airway inflammation and thrombogenicity. The IT pretreatment with DEX (0.5 mg/kg) showed a partial but parallel inhibition of all of these parameters. Pretreatment with SC (40 mg/kg, IP) strongly inhibited airway inflammation, thrombogenicity, and histamine release.'] Does pharmacological stabilization of mast cells abrogate late thrombotic events induced by diesel exhaust particles in hamsters?