HMGB1 and systemic lupus erythematosus: Toll-like receptor 4 (TLR4), a transmembrane non-catalytic protein expressed on the cell surface, is a downstream target of HMGB1 and is involved in the induction of the inflammatory program and in the progression of SLE and atherosclerosis (Michelsen et al., 2004; Hu et al., 2016).