Therefore, we extended our investigation into OSA patients with long-term continuous positive airway pressure (CPAP) treatment, hypertension, or excessive daytime sleepiness (EDS) by analyzing whole-genome gene expression profiles of PBMC in three comparisons: (1) treatment-naïve moderate to very severe OSA patients versus subjects with primary snoring; (2) moderate to very severe OSA patients with hypertension or EDS versus those without hypertension or EDS, respectively; (3) treatment-naïve very severe OSA patients versus those receiving at least one year of adequate CPAP treatment. Overall design: We analyzed whole-genome gene expression profiles of peripheral blood mononuclear cells from 48 patients with sleep-disordered breathing stratified into four groups: primary snoring (PS), moderate to severe OSA (MSO), very severe OSA (VSO), and very severe OSA patients with long-term continuous positive airway pressure (CPAP) treatment (VSOC).