Serum IL-17A levels in the severe group were elevated (median value: control group 0.89 pg/ml, mild OSAHS 1.02 pg/ml, moderate OSAHS 1.18 pg/ml, and severe OSAHS 1.62 pg/ml; p < 0.05) and positively correlated with AHI (r = 0.52, p < 0.05) but negatively related to the mean O2 saturation and lowest O2 saturation (r = −0.349, p < 0.05; and r = −0.336, p < 0.05, respectively). This evidence concerns the gene IL17A and obstructive sleep apnea syndrome.