TNF and postural orthostatic tachycardia syndrome: Other elevated proinflammatory biomarkers included IL-17 (p < 0.0001), MCP-1 (p < 0.0002), and RANTES (p < 0.0001; an indicator of platelet activation), whereas the proinflammatory TNFα was found to be at a similar concentration to that in non-POTS subjects.