HMGB1 and rheumatoid arthritis: HMGB protein family has been confirmed to be involved in cellular proliferation, apoptosis, oxidative stress and inflammatory responses in a variety of diseases.[25–27] In autoimmune diseases, Tsakalidou et al demonstrated that serum HMGB1 levels correlated with disease activity and severity in systemic lupus erythematosus patients.[28] A review by Taniguchi et al found that multiple functions of the HMGB protein family (HMGB1, 2, 3, and 4) play a complex role as intrinsic and endogenous regulators in rheumatoid arthritis.