LCN2 and systemic lupus erythematosus: Iron accumulation has been detected in the kidneys of both SLE patients and lupus mice (36, 37), and multiple molecules related to iron metabolism [such as ferritin, transferrin, ceruloplasmin, and neutrophil gelatinase-associated lipid carrier protein (NGAL)] have been identified as biomarkers of SLE and/or LN, which are associated with disease activity and/or renal involvement (38–43).