CD8A and obstructive sleep apnea syndrome: Although it has been reported that NLR, PLR, and CD4+/CD8+T ratio can serve as a biomarker for OSA in diagnosis (Rha et al., 2020; Domagała-Kulawik et al., 2015; Kıvanc et al., 2018), these studies neither provided any necessary validation in separate samples nor exhibited the AUC of ROC; the ROC in our study failed to support their diagnostic value for the sake of their poor AUCs.