CMA1 and deep vein thrombosis: The role of MCs in allergic inflammation, a risk factor for DVT and PE,19 has been well documented.20 MC granules contain potent anticoagulants, such as heparin and tPA (tissue-type plasminogen activator); endothelial activators (histamine and tumor necrosis factor-α); and many enzymes (tryptases, chymases, and others).21,22 In tissues, MCs are located in the vicinity of blood vessels,23 and their presence at the site of human DVT has been reported.24