Immune activation, with an increase in proinflammatory cytokine concentrations, including IL-6, TNFα, and IL-1 [2, 44, 45], has been rather inconsistently, for example [32], demonstrated in CFS, may be secondary to insufficient glucocorticoid signaling [7], and may result in pain, fatigue, cognitive deficits, and other symptoms which are characteristic of CFS [12, 16, 38, 46]. Here, TNF is linked to myalgic encephalomeyelitis/chronic fatigue syndrome.