TNF and rheumatoid arthritis: Interestingly, the only study conducted in RA patients with active disease receiving daily melatonin at night over six months reported low antioxidant profiles in patients, increased neopterin concentrations and erythrocyte sedimentation rates (inflammation indicators) and no changes in pro-inflammatory cytokine levels (TNF-α, IL-1β and IL-6), but these effects were not associated with any changes in clinical symptoms [237].