In advanced atherosclerosis, foam cell formation and production of matrix-degrading metalloproteinase (MMPs) by activated macrophages are significantly induced by CD40-CD40L cross-talk and stromal cell derived factor 1 (SDF-1) following platelet activation, which will lead to plaque destabilization and rupture (100, 101). This evidence concerns the gene CXCL12 and atherosclerosis.