AGER and systemic lupus erythematosus: In human SLE, C1q collaborates with high mobility group box 1 protein (HMGB1) to promote M2 macrophage polarization from monocytes through the receptor for advanced glycation end products (RAGE) and leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) in lipid rafts 56.