Neutrophil Extracellular Traps and Lupus Nephritis

Lupus Nephritis is one of the most severe organ manifestations of systemic lupus erythematosus and represents a major cause of morbidity, chronic kidney disease, and long-term mortality. Despite significant advances in immunosuppressive therapies, a substantial proportion of patients fail to achieve sustained renal remission or progress to end-stage renal disease, highlighting the need for improved understanding of disease mechanisms and more reliable biomarkers for disease monitoring and therapeutic response

Inclusion criteria for LN group: 1. Adult patients (≥ 18 and \> 60 years) of either sex. 2. Fulfill the 2019 EULAR/ACR Classification Criteria for Systemic Lupus Erythematosus (SLE) \[11\]. 3. Diagnosis of active lupus nephritis requiring a renal biopsy as per standard clinical indications (e.g., proteinuria ≥ 0.5 g/24h, active urinary sediment, unexplained rise in serum creatinine). 4. Availability of an adequate renal biopsy specimen for histopathological evaluation according to the International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2018 classification. 5. Patients planned to initiate standard induction therapy (e.g., mycophenolate mofetil or cyclophosphamide with corticosteroids). 6. Provision of written informed consent. Inclusion Criteria for Control Groups: 1\) SLE without nephritis: Patients meeting SLE criteria without any clinical or laboratory evidence of renal involvement (normal urinalysis, proteinuria \< 0.3 g/24h, normal serum creatinine). Exclusion Criteria: * Participants will be excluded if ANY of the following criteria apply: 1. Other Kidney Diseases: * Presence of, or suspicion of, any other primary or significant secondary kidney disease unrelated to SLE (e.g., diabetic nephropathy, hypertensive nephrosclerosis, IgA nephropathy, significant drug-induced nephrotoxicity, rheumatoid arthritis, positive HBs antigen or HCV antibody). 2. Confounding Clinical Conditions: * Presence of an active or recent major infection (e.g., sepsis, pneumonia, UTI) at the time of enrollment, as infection can significantly alter immune markers. * Presence of advanced chronic kidney disease (CKD Stage 4 or 5) predating the diagnosis of SLE. 3 · Pregnancy or lactation. 4\. Recent use (within the last 3 months) of biologic therapies that may affect neutrophil function or NET formation. 5\. Use of medications known to significantly alter neutrophil activity. 6. History of malignancy.