Se is responsible for the activity of the glutathione peroxidase (GSH-Px) enzyme;Se may also inhibit osteoclastogenesis by suppressing receptor activator of nuclear factor kappa-Β ligand (RANKL) expression on CD4+ T lymphocytes;Se nanoparticles (SeNPs) show potential usefulness in the treatment of RA because of their antioxidant and anti-inflammatory properties;. The gene discussed is CD4; the disease is rheumatoid arthritis.