PPARA and myalgic encephalomeyelitis/chronic fatigue syndrome: In ME/CFS, GSA identified enrichment of gene sets including peroxisome proliferator–activated receptors (PPAR) signaling (UES = 1.9043, DES = –1.4736), fatty acid metabolism (UES = 1.7918, DES = –1.5557), NK receptors (UES = 1.7526, DES = –1.3492), glycolysis and glucose import (UES = 1.7244, DES = –1.5434), anergy (UES = 1.6924, DES = 1.4338), B cell exhaustion (UES = 1.6487, DES = –1.5374), and epigenetic modification (UES = 1.5496, DES = 0.9327).