MMP9 and psoriasis: The serum levels of IL-16 are also positively correlated with the psoriatic area and severity index score, indicating that IL-16 is a potential marker for evaluating the activity of psoriasis.[45] Moreover, Park et al have suggested that IL-16 can induce the migration and invasion of vascular smooth muscle cells through the p38MAPK/Sp-1/MMP-9 pathway.