The role of high mobility proteins (HMGB1) in systemic lupus erythematosus

Abstract Introduction The high mobility group box 1 proteins (HMGB1) are non-histone nuclear proteins reported to be present at high levels in some autoimmune diseases, such as systemic lupus erythematosus (SLE). Likewise, in contrast to healthy individuals, patients with SLE have a higher prevalence of anti-HMGB1 antibodies, and these levels have also been associated with heightened disease activity. This article will discuss the involvement of these proteins in immunology, and review the evidence supporting their clinical importance in SLE. Materials and methods A narrative review was conducted based on a search of the literature up to October 2018, of articles describing the function, structure, prevalence and importance of HMGB1 in different manifestations of SLE. Articles focusing on the presence of HMGB1 and/or its antibodies in patients with SLE or other autoimmune diseases were also reviewed. Results A total of 69 articles were found. These articles were the foundation to define the structure and functions of HMBG1, including its role as a cytokine released by immune cells in inflammatory processes and necrosis. Additionally, a description of its functions in phagocytosis and NETosis - that have an impact on autoimmune diseases, primarily in SLE - was included. Conclusion HMGB1 proteins and anti-HMGB1 antibodies are elevated in the serum of patients with SLE, in contrast with healthy individuals or non-severe presentations of the disease; this suggests that they may play a role as a biomarker of disease activity.