TLR2 and obstructive sleep apnea syndrome: In recent years, additional research on cellular immune has reported that macrophage polarization towards M1 subsets (Khalyfa, Kheirandish-Gozal & Gozal, 2018), increased ratio of NLR (Rha et al., 2020), PLR (Kıvanc et al., 2018), CD8+T/CD4+T (Domagała-Kulawik et al., 2015), and Th17/Treg (Reale et al., 2020), as well as DNA methylation of toll-like receptor 2/6 (Huang et al., 2020) in OSA patients, suggesting possible reactions to new endogenous antigens.