HMGB1 and systemic lupus erythematosus: HMGB1 levels in serum of SLE patients were increased and correlated with disease activity scores. High levels of HMGB1 converted monocytes into M1 type, promoted inflammation, and reduced the clearance of apoptotic cells. HMGB1 could also activate pDC and mDC and promote the release of NETs from neutrophils. HMGB1 could promote the rapid and abundant aggregation of ALD-DNA in macrophages through clathrin/alveolar protein-1. Serum HMGB1 could be used as a biomarker of NPSLE.