Interleukin-18 (IL-18) is a cytokine that is capable of inducing production of interferon-y (IFN-y) in T lymphocytes and of supporting differentiation of the TH1 subset of helper T lymphocytes. IL-18 production is increased by stimulation from IL-1p. The resultant increase in IL-18 and the binding to the IL-18 receptor on macrophages and vascular smooth muscle cells results in upregulation of IFN-y, MMPs, various cytokines, and vascular cell adhesion molecules (VCAMs). Furthermore, IL-18 has been found in atherosclerotic plaques. Increased IL-18 expression results in a "vulnerable plaque morphology," defined by thin cap atheroma and more intraplaque hemorrhage.22 However, the exact mechanism by which IL-18 contributes to atherosclerotic disease remains controversial.
Although increased IL-18 expression has been noted in patients with ACS as well as in those with known coronary artery disease who are at increased risk of death from cardiovascular causes, the role of IL-18 in ACS is still undetermined and needs to be understood in relation to other factors. The ratio of IL-18, a pro-inflammatory cytokine, to that of IL-10, an anti-inflammatory cytokine, may be more important than the actual quantity of IL-18 itself.23 Nevertheless, future investigation is necessary before the utility of this cytokine is fully understood.
Was this article helpful?