Urinary TWEAK Level as a Marker of Lupus Nephritis Activity

Abstract

Systemic lupus erythematosus (SLE) is an autoimmune disease which can cause multisystem affection. Lupus nephritis (LN) occurs in up to 50% of SLE patients. It is one of the most serious SLE complications associated with significant morbidity and mortality and it is the major predictor of poor prognosis. Novel biomarkers that are able to discriminate lupus renal activity and its severity, predict renal flares, and monitor treatment response and disease progress are clearly necessary. TWEAK is a multifunctional cytokine that belongs to the TNF-ligand superfamily. It was proved that TWEAK promotes renal damage and drives disease progression in early as well as later stages of the disease. In response to TWEAK stimulation, glomerular cell types including vascular endothelial cells, mesangial cells and podocytes produce inflammatory mediators which contribute to tubule-interstitial inflammation, renal vascular injury, tubular damage in LN and tubule-interstitial renal fibrosis. The present study aimed to clarify the role of uTWEAK in diagnosis of lupus nephritis and its correlation to renal disease activity.All subjects involved in this study were free from any other conditions that can affect uTWEAK level, such as diabetes mellitus, urinary tract infections and mixed connective tissue disorders. The study included 60 SLE patients, in addition to 20 age-matched healthy females as a control group. SLE patients were classified into 2 groups based on the presence or absence of LN, as follows:

• Group I (20 patients): included Non-renal disease group. • Group II (40 patients): Renal disease group, and this group was further subdivided according to renal disease activity into: 1. Group IIa (n=20): patients with active renal disease. 2. Group IIb (n=20): patients with inactive renal disease.