Serum Interleukin-15 Concentration in Patients With Essential Hypertension

Background Interleukin (IL)-15 is one of the cytokines produced by neutrophils and monocytes/macrophages, and its expression is found immunohistochemically in inflammatory cells adjacent to vulnerable atherosclerotic plaques. However, the influence of systemic IL-15 on cardiovascular disease is still unclear. Therefore, we designed clinical investigations to clarify the relationship between cardiovascular complications and serum IL-15 levels. Methods and Results Three hundred ninety-nine patients with essential hypertension were analyzed. We divided the study subjects into the following three groups according to the modified World Health Organization–International Society of Hypertension classification of 1999: patients with no organ damage (n = 213), patients with mild organ damage (n = 128), and patients with severe organ damage (n = 58). We measured serum IL-15, highly sensitive C reactive protein, IL-6, soluble intercellular adhesion molecule, and soluble vascular cell adhesion molecule levels. Serum IL-15 concentration in patients with severe organ damage was significantly higher than that in those with no organ damage (P< .01) and those with mild organ damage (P< .01). Serum IL-15 concentration in patients with coronary artery disease or peripheral artery disease was significantly higher than that in those without coronary artery disease or peripheral artery disease. Moreover, serum IL-15 concentration in patients with lacunar infarction was significantly higher than that in those without lacunar infarction (P< .005). By multiple linear logistic regression analysis, serum IL-15 concentration was independently correlated with cardiovascular disease. Conclusions These data suggest that a systemic inflammatory response involving IL-15 might be involved in the occurrence of cardiovascular disease in patients with essential hypertension.