While an emerging body of evidence over the last 10 years has highlighted the role of altered cellular metabolism in the pathogenesis of RA (Fig. 1), the concept was originally hypothesized in the 1970s where studies demonstrated increases in the level of metabolites in synovial fluid and in the activity of glyceraldehyde 3-phosphate dehydrogenase and lactate dehydrogenase in RA synovial cells [11, 12]. Here, GAPDH is linked to rheumatoid arthritis.