In addition, when T cells are treated with RA-SF, osteopontin expression is elevated; on the other hand, overexpression of osteopontin induces proinflammatory chemokines and cytokines and activates nuclear factor-kappa B.21Osteopontin deficiency is consistently shown to prevent the destruction of joint cartilage and joint swelling through suppression of chondrocyte apoptosis and angiogenesis in the RA model.21 Here, SPP1 is linked to rheumatoid arthritis.