We also observed hypomethylation of promoters of MMP14, MAP4K4, MAPK12 and CREB5 (S6 and S7 Tables) possibly activating the TNF signaling pathway, that fits with the reported over-expression of pro-inflammatory cytokines [60] in ME/CFS. Here, MAP4K4 is linked to myalgic encephalomeyelitis/chronic fatigue syndrome.