Phosphorylation of MEK1/2 and p38 has been implicated in the pathogenesis of many chronic inflammatory diseases and increased production of IFN-γ may be a result of increased MEK1/2 and p38 in CD56brightCD16dim/− NK cells from CFS/ME patients [27, 46, 63]. This evidence concerns the gene MAPK1 and myalgic encephalomeyelitis/chronic fatigue syndrome.