The combination of the CD8+ and MAIT markers had an AUC of 0.7843 (p < 0.0001) (Fig. 8f), indicating that the activation, inflammation, cytotoxicity and immunosenescence markers have the capability to discriminate between people with mild/moderate or severe ME/CFS disease. This evidence concerns the gene CD8A and myalgic encephalomeyelitis/chronic fatigue syndrome.