TNF and internal carotid artery stenosis: Patients with untreated SCH who underwent thromboendarterectomy due to asymptomatic severe internal carotid artery stenosis presented higher plasma TNF-α, IL-6, and interleukin-18 levels, and their atherosclerotic plaques presented an active inflammatory reaction with higher TNF-α levels and other characteristics of instability compared with non-SCH controls [26].