FPR2 and obstructive sleep apnea syndrome: Subgroup analysis in treatment-naïve sleep disordered breathingpatients, including PS and treatment-naive OSA groups, showed that both FPR1 expression (7.24±3.2 vs. 4.11±1.67 MFI, p<0.001) and FPR1/FPR2 MFI expression ratio (0.78±0.38 vs. 0.43±0.19, p = 0.001) on neutrophil were significantly increased in treatment-naïve OSA patients as compared with that in PS group.