Journal of Clinical and Cellular Immunology
Open Access

Abstract

Urine Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in Lupus Nephritis: A Prospective Longitudinal Study

Sabah Alharazy, Norella CT Kong, Marlyn Mohd, Shamsul A Shah, Arbaiyah Ba´in and Abdul Halim Abdul Gafor

Objective: Urine neutrophil gelatinase-associated lipocalin (uNGAL) is increased in active lupus nephritis (LN). In this longitudinal study, we further evaluated the role of uNGAL as a potential marker for monitoring LN response to treatment and/or early relapse.
Methods: uNGAL levels were measured at baseline and at 2- and 4-months in 100 patients with biopsy-proven LN. They were divided into 2 groups - active LN [non-remission (NR) and relapses] and inactive LN [complete remission (CR) or partial remission (PR)]. Renal function test, urinary parameters, lupus serology and renal SLE disease activity index-2K (renal SLEDAI-2K) were analyzed to determine their associations with uNGAL.
Results: At baseline, there were 47 patients in the active group (42 NR and 5 relapsed) and 53 in the inactive group (51 CR and 2 PR). With treatment, the number with active LN declined to 29 (27 NR and 2 Relapsed) at 2 months and 22 (16 NR and 6 Relapsed) at 4 months respectively. Conversely, the number in the inactive group increased to 71 (61 CR and 10 PR) at 2 months and 78 (59 CR and 19 PR) at 4 months respectively. At each visit, uNGAL levels (ng/mg creatinine) were significantly higher in the active group especially relapses and were significantly associated with proteinuria and renal SLEDAI-2K. Receiver operating characteristic (ROC) curves showed that uNGAL was a potential biomarker for LN. Nonetheless, multiple logistic regression analysis showed that only serum albumin and proteinuria and not uNGAL were independent predictors of LN activity.
|Conclusions: uNGAL was increased in active LN especially flares. Although not an independent predictor for LN activity, uNGAL could serve as an adjunctive marker when the clinical diagnosis of LN especially early relapse remains uncertain. Larger and longer studies are indicated.