PKM and rheumatoid arthritis: Representative immunofluorescence images show co-localisation of the oxidative stress marker 4-HNE with glycolytic proteins (GAPDH, PKM2, GLUT1) and a mitochondrial marker (ATP5B) in inflamed ST of patients with RA: GAPDH, PKM2, GLUT1, and ATP5B (red); 4-HNE (green); DAPI (blue); merged images (yellow).