TNF and irritable bowel syndrome: This finding is consistent with the systemic response to enteric microorganisms reported by Maes et al in a number of reports and demonstration of correlation between this systemic response and pathological ME/CFS processes and symptoms, including higher serum IL-1, TNFα, and neopterin levels, autoimmune responses to serotonin, and increased symptoms of irritable bowel syndrome [9,23–26].