Six pairs of proteins were significantly and negatively correlated in the ME/CFS group only (orange squares, Fig. 5c), with 3 including SERPINA7, and one unique to the control group (SERPINA1/KNG1, r = − 0.82, q < 0.01, light blue square, Fig. 5c). This evidence concerns the gene SERPINA1 and myalgic encephalomeyelitis/chronic fatigue syndrome.