TNF and obstructive sleep apnea syndrome: Ryan et al. (18) found that circulating TNF-α levels were higherin OSA patients (2.56 pg/mL; IQR, 2.01 to 3.42 pg/mL) than in control subjects (1.25pg/mL; IQR, 0.94 to 1.87 pg/mL; P<0.001).