TNF and sleep disorder: Sleep disorders are also associated with an increased systemic immune and inflammatory dysregulation, mainly due to hyperexpression of pro-inflammatory mediators and cytokines (e.g., IL-1β, IL-2, IL-6, TNF-α, IL-18, sTNF-R1, and sTNF-R2), and intermittent hypoxia-induced oxidative stress [60,173,178].