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 This evidence concerns the gene PLAT and deep vein thrombosis.