In CFS/ME, cytokines such as IL-4, IL-10, IL-17, tumor necrosis factor- (TNF-) α, and interferon- (IFN-) γ have been observed to be equivocally expressed in the serum and plasma samples and following mitogenic or inflammatory stimulation of lymphocytes [12–15]. The gene discussed is IL17A; the disease is myalgic encephalomeyelitis/chronic fatigue syndrome.