IL6 and obstructive sleep apnea syndrome: In patients with OSA, an increase in blood biomarkers has been described as inflammation biomarkers (C-reactive protein (CRP) and tumor necrosis alpha factor (TNF-alpha)) [21,22], inflammatory cytokines (interleukin 6 (IL-6), interleukin 8 (IL-8)) [21], endothelial dysfunction markers (nitric oxide) [23], hypercoagulability disorders (D-dimer, tissue factor, thrombin and antithrombin levels) [24] and oxidative stress markers (reactive oxygen species (ROS)) [25].