Untreated sleep apnea is associated with immune activation, as characterized by increased levels of inflammatory markers such as C-reactive protein (CRP) and proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), which may be mediated by hypoxemia and related oxidative stress [21–24]. This evidence concerns the gene IL6 and sleep apnea syndrome.