TMSS Medical College Journal

Objective: In this study our main goal is to evaluate the role of urinary N-acetyl-beta- D-glucosaminidase to determine the activity of lupus nephritis. Materials and Methods: This cross-sectional prospective observational type of study was conducted among 60 diagnosed lupus nephritis patients (active and inactive) at Department of Nephrology, Dhaka Medical College Hospital, Dhaka., from January 2017 to December 2017. Results: In this study, 62(mIU/ml) is the best uNAG cutoff value for determination of lupus nephritis activity. Among 29 active lupus nephritis cases raised uNAG was found in 28 cases and among 31 inactive lupus nephritis cases raised uUNAG was found in 2 cases. uNAG in determination of lupus nephritis activity showed accuracy, sensitivity, specificity, PPV and NPV were 0.950, 0.966, 0.935, 0.933 and 0.967 respectively. Conclusion: uNAG is a useful biomarker for determination of lupus nephritis activity.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder characterized by the activation of T and B lymphocytes, production of auto-antibodies and formation of immune complexes causing wide spectrum of tissue and organ damage.’ The overall prevalence of SLE ranges from 1.4 to 21.9% cases per 100,000 people.> N-Acetyl-B-d-glucosaminidase (NAG) is a lysosomal brush border enzyme of proximal renal tubular cells that is normally excreted in low amounts in urine. It has been proposed as a valuable marker for renal tubular dysfunction because its relatively large molecular weight (>130kD) precludes filtration by the glomerulus.” The urinary excretion of NAG is increased in subjects exposed to substances that are toxic to renal tubular cells as lead, mercury and contrast media, nephrotoxic drugs as aminoglycosides, antineoplastic drugs as methotrexate and cisplatin.*® It is also increased in various human glomerular diseases, including diabetic nephropathy.” Moreover, it has been proposed that uNAG activity is probably an indicator of the increased lysosomal turnover that occurs when increased protein is presented to the tubular cells. Increased uNAG activity in patients with glomerulonephritis and proteinuria has been suggested as indicating functional changes within the kidney, rather than renal tubular damage.’ In this study our main goal is to evaluate role of urinary N-acetyl-beta- D-glucosaminidase to determine the activity of lupus nephritis.