IL6 and obstructive sleep apnea syndrome: High circulating levels of proinflammatory cytokines, such as tumour necrosis factor α (TNF-α), interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), and vascular cell adhesion molecule 1 (VCAM-1), have been found in OSA patients [11–14].