THE VALUE OF LIPOCALIN-2 IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract

Lupus nephritis (LN) is a prominent feature in SLE present in 15-30% of patients with lupus at the time of the initial diagnosis and 30-50% during the disease progression. Present assessment of SLE patients includes a urine analysis, creatinine clearance and measurement of urinary proteins. However, these parameters are not predictive of the classification and severity of nephropathy seen at biopsy nor they have been shown to be reliable in evaluating treatment response. This study represents one of the studies that aimed to assess the role of lipocalin-2 in detecting the renal disease activity in patients with SLE in order to detect an early, clinically accurate and available diagnostic tool for the diagnosis of lupus nephritis. Moreover the correlation of the urinary level of lipocalin-2 with the renal parameter of the SLEDAI score were evaluated. In addition, a correlation of the urinary lipocalin-2with renal functions tests also were evaluated. The present study included thirty SLE patients who were selected from outpatient clinic of Rheumatology and Rehabilitation of Ain Shams University Hospital, and diagnosed according to American College of Rheumatology revised criteria for SLE. Renal involvement of these patients was assessed by renal parameter of the SLEDAI score and they were matched with fifteen healthy individuals as the control group. All were subjected to full clinical history and examination, serum creatinine, blood urea nitrogen (BUN) and serum complements as well as urinary and serum lipocalin-2 by ELISA technique. In this study urinary lipocalin-2 were significantly higher in the SLE patients compared to control group, also urinary lipocalin-2 levels were higher in patients with lupus nephritis than in the SLE patients without nephritis or the control group. In addition, the levels of lipocalin-2 in the serum of lupus patients showed no statistically significant different from those of the serum of normal individuals. Moreover, no significant difference was found in the levels of serum lipocalin-2 between all patients and control group.Also no significant difference was found in the levels of serum lipocalin-2 between patients with lupus nephritis group and those without lupus nephritis and there was no association between the serum, and urinary levels of lipocalin-2. As regards the correlation study between urinary lipocalin-2 andrenal parameter ofthe SLEDAI score and blood urea nitrogen (BUN), the results revealed a positive correlation. In addition urinary lipocalin-2 correlated with serum creatinine. Moreover the diagnostic performance of lipocalin-2 was evaluated in the present study and our results showed that lipocalin-2 could serve as an early predictor of renal flarein SLE. This may eventually enable early treatment and improve the significant short and long term morbidity.