C3 and anti-neutrophil cytoplasmic antibody-associated vasculitis: Previous studies have identified a range of prognostic markers for LN, including traditional biomarkers, such as proteinuria and serum C3, as well as emerging markers like serum primary ANCA-associated vasculitis (ANCA), urinary ALCAM, and indicators from renal biopsies, such as arteriolar C4d deposition, interstitial fibrosis, and tubular atrophy (IFTA) [40].