Which of these factors predominate in triggering dengue-associated endothelial permeability is widely debated, but likely candidates include vascular endothelial growth factor (VEGF), platelet activating factor (PAF), leukotrienes, matrix metalloproteinase-9 (MMP-9), sphingosine-1-phosphate (S1P), DENV NS1 protein (reviewed in [8]) as well as MIF [31] and glycosaminoglycans such as hyaluronic acid and heparan sulfate [32]. This evidence concerns the gene MMP9 and dengue disease.