Besides, up-regulated immune-related genes in patients affected by CFS such as lactotransferrin, defensin-α1, integrins [8], CMRF35 antigen, IL-8, HD protein [10], and cathepsin C [9] are supportive of the notion that CFS is characterized by immune system activation. This evidence concerns the gene CXCL8 and myalgic encephalomeyelitis/chronic fatigue syndrome.