Correlation of Urinary Neutrophil Gelatinase Associated Lipocalin with Routine Biomarkers used to Detect Kidney Injury in Systemic Lupus Erythematosus Patients with and without Nephritis

Abstract

Systemic lupus erythematosus is associated with various complications with kidney involvement Lupus Nephritis(LN) being the most common. The routine biomarkers for the diagnosis of Lupus Nephritis have low specificity and sensitivity leading to delayed diagnosis of the condition thus increasing the rate
of mortality and morbidity. Hence there is need of a new biomarker showing correlation with the old biomarkers indicating the severity of renal damage. This search for a new marker to detect kidney involvement in patients with lupus induced nephritis can help to diagnose patients with kidney involvement at an early stage leading to timely initiation of therapy and decrease the rate of mortality and morbidity in these patients.
Objective: This study was designed to find out correlation of Neutrophil gelatinase associated lipocalin (uNGAL) with the biomarkers routinely used to measure kidney injury in patients with SLE and therefore finding the efficacy of NGAL in detection of renal involvement in these patients.
Methods: It is a cross sectional study conducted in Deptt. of Biochemistry and Chemical Pathology, Sheikh Zayed Hospital Lahore from June 2015 to June 2016 Eighty Four (n=84) SLE patients were selected for this study from Sheikh Zayed Hospital Lahore. These cases were divided into two equal groups (n=42) A and B. Group A comprised of SLE cases without kidney involvement and group B had cases with biopsy proven lupus nephritis. Urinary NGAL, serum and urinary creatinine and microalbuminuria were measured in both groups. Correlation of NGAL with serum and urinary creatinine, albumin creatinine ratio and creatinine clearance was calculated using Pearson's correlation and scatter plots were drawn for both groups.
Results:This study revealed that uNGAL correlated positively with creatinine and ACR (albumin creatinine ratio) and correlated in a negative manner with Creatinine clearance of the patients. However, the new biomarker showed no correlation with creatinine measured in urine.
Conclusion: Our study indicated that the new bio-marker i.e. uNGAL had a significant correlation with renal disease activity of SLE patients and thus can be used to assess the status of renal involvement in lupus patients.