Urine Neutrophil Gelatinase-Associated Lipocalin as A Biomarker inLupus Nephritis — Relation with Severity of Disease and TreatmentResponse

Abstract

Introduction: Lupus nephritis, a severe form of systemic lupus erythematosus (SLE), predominantly affects young women and leads to significant renal damage if untreated. Due to the invasive nature of renal biopsy, non-invasive biomarker like urine neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a promising biomarker for monitoring lupus nephritis. NGAL levels correlate with disease severity and treatment response, providing valuable insights into renal damage and therapeutic effectiveness. Materials & Methods: This prospective observational study was carried out in the Nephrology department at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, from March 2023 to August 2024. It involved adult patients (age ≥ 18 years) diagnosed with SLE and lupus nephritis. A total of 52 respondents were enrolled using convenience sampling. Ethical approval was secured from the Institutional Review Board (IRB) of BSMMU. Renal biopsies and urine samples were collected for analysis, and patients were followed up at six months. Results: The study population predominantly consisted of young females (92.3%), with the majority (69.2%) being under 30 years of age and having normal weight (67.3%). Most respondents were married (80.8%) and from urban areas (57.7%). Histological classification revealed 57.7% respondents had class IV lupus nephritis. All patients received Hydroxychloroquine, 61.5% received Cyclophosphamide + Corticosteroid, 23.1% received MMF + Corticosteroid and 15.4% received only Corticosteroid. A complete response was observed in 67.3% of patients. Urine NGAL levels, a marker for renal inflammation, were highest in class IV patients at both baseline (2.14 ± 1.01 ng/mL) and 6 months (1.20 ± 0.59 ng/mL) and significantly (p < 0.05) correlated with disease severity. Higher mean urine NGAL levels were found in proliferative group at both baseline (2.00 ± 0.96 ng/mL) and 6 months (1.11 ± 0.56 ng/mL) Proliferative lupus nephritis patients had higher serum creatinine, and lower serum albumin levels compared to non-proliferative patients. Lower mean urine NGAL level was observed for patients with complete response at both baseline (1.39 ± 0.48 ng/mL) and 6 months (0.80 ± 0.25 ng/mL). Conclusion: The results of this study highlight the critical role of urine NGAL in evaluating disease severity and treatment response in lupus nephritis. This biomarker offers significant potential for enhancing clinical management and guiding therapeutic decisions. To fully establish its utility in routine clinical practice, further large-scale, multi-center studies are necessary.