IGFBP2 and systemic lupus erythematosus: Insulin-Like Growth Factor Binding Protein 2 (IGFBP2, C+A− quadrant), Targeting and neutralizing IGFBP2 (C+A− quadrant) as a lupus nephritis biomarker shows potential as a new option in treating patients with lupus nephritis, an advanced complication of SLE targeting the kidneys with few workable treatments [92,93].