Interleukin 17 in vascular inflammation

Interleukin (IL)-17 (also known as IL-17A) is produced by activated T cells. It is a marker cytokine of the T_H17 lineage. IL-17 production is induced in infections, autoimmune diseases and other inflammatory events. IL-17 is involved in host defense, but also inflammatory tissue destruction. Vascular disease, mostly in the chronic form of atherosclerosis, is a leading cause of death. While normal vessels harbor only few leukocytes, large numbers of both innate and adaptive immune cells accumulate during vascular inflammation, both in chronic forms such as atherosclerosis and in acute vasculitis. IL-17 has a role in chronic vascular inflammation of atherosclerosis and possibly hypertensive vascular changes. In acute inflammation, IL-17 is elevated and may be causally involved in the autoimmune vasculitides including vasculitis in systemic lupus erythematodes. Blood vessels are important targets in alloimmune graft rejection and a number of studies provide data on a role of IL-17 in this context. This brief review summarizes the currently available evidence for and putative mechanisms of action of IL-17 in mouse models of and human vascular disease.