Insulin‐like growth factor binding protein‐2 as a biomarker for lupus nephritis

Abstract

AbstractBackgroundLupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus (SLE). The aim of this study was to identify serum insulin‐like growth factor binding protein‐2 (IGFBP‐2) as a novel non‐invasive biomarker for clinical disease and renal pathology in pediatric LN.MethodsA cross‐sectional study on 93 newly diagnosed LN children who were biopsy‐proven, 35 SLE children with no renal involvement as disease controls, and 30 healthy controls (HC) with age and gender‐matched. All children were ELISA tested for serum IGFBP‐2 levels. Clinical, laboratory, histopathological features of LN patients were collected.ResultsCompared to SLE or HC, serum IGFBP‐2 levels were significantly elevated in LN patients. Serum IGFBP‐2 could distinguish LN patients from two others (AUC = 0.937, p < 0.001 for LN vs. HC; 0.897, p < 0.0001 for LN vs. SLE). In ROC analysis, IGFBP‐2 had a higher ability to differentiate between LN and SLE than anti‐dsDNA with AUC values of 0.895 and 0.643, respectively. LN children with systemic lupus erythematosus disease activity index (SLEDAI) in high activity had significantly higher IGFBP‐2 concentration than the others with SLEDAI in moderate activity. Serum IGFBP‐2 correlated with albuminemia levels (r = 0.415, p < 0.001), urine protein‐to‐creatinine levels (r = 0.316, p = 0.002), estimated glomerular filtration rate (r = 0.438, p < 0.001), complement C3 (r = 0.333, p = 0.001). More importantly, serum IGFBP‐2 correlated with the activity index of renal pathology (r = 0.312, p = 0.007, n = 75).ConclusionsSerum IGFBP‐2 is a promising biomarker for pediatric lupus nephritis, reflective of disease activity and activity index in renal patients.