Further investigations into the regulation of MEK1/2 and p38 in CD56brightCD16dim/− NK cells from CFS/ME patients are required to determine if a regulatory mechanism such as MPK1 may contribute to increased MEK1/2 and p38 activity and IFN-γ cytokine production. This evidence concerns the gene MAPK14 and myalgic encephalomeyelitis/chronic fatigue syndrome.