Cell surface FPR2 protein expressions on neutrophil were decreased in the treatment-naive OSA (9.71±3.32 MFI, p = 0.001/adjusted p<0.001) group as compared with that in the HS (14.93±5.11) group, and increased in the severe OSA on CPAP (15.89±6.78 MFI) group as compared with that in the treatment-naive OSA (p<0.001/adjusted p<0.001) group and that in the PS (p = 0.001/adjusted p = 0.014) group, respectively (Fig 2B). This evidence concerns the gene FPR2 and obstructive sleep apnea syndrome.