TNFRSF1A and obstructive sleep apnea syndrome: OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals (p = 1.8 × 10−13 to 4 × 10−8).