Abstracts：Objective：To study urinary neutrophil gelatinase-associated lipocalin (uNGAL) in the patients with systemic lupus erythematosus (SLE) and analyze its association with disease activity and pathology classification for lupus nephritis (LN). Methods：The serum and urine samples of 104 SLE patients and 60 controls were collected. SLE patients were further divided into lupus nephritis (LN, n=63) and non-nephritis SLE (n=41). The controls consisted of 30 patients with non-SLE autoimmune diseases and 30 healthy volunteers. The concentrations of sNGAL and uNGAL were measured by latex enhanced turbidimetric immunoassay method. Results：uNGAL levels in the patients with LN were significantly higher than those without LN (P<0.01) but the difference of sNGAL levels between the two groups did not showed statistical significance. In the patients with LN, uNGAL levels in active LN were higher than those in inactive LN (0.8±0.4 ng/mg Cr vs 0.5±0.3 ng/mg Cr, P<0.01). uNGAL levels positively correlated with the renal score of the Systemic Lupus Erythmatosus Disease Activity Index (SLEDAI) (r=0.364, P<0.01) . The ROC curve of uNGAL showed the level of uNGAL at cut off point (0.585 ng/mg Cr) exhibited high sensitivity and specificity (70.73% and 77.27% respectively) (P<0.01). The area under ROC curve was 0.756. The comparison of uNGAL levels among the groups with different WHO classes of LN yielded no significant difference (P>0.05), though the patients with LN class Ⅲ and Ⅳ had elevated uNGAL. Conclusion：uNGAL levels elevated promptly in SLE patients with renal involvement. uNGAL represents a novel sensitive biomarker for predicting disease activity in LN. There was no significant difference in uNGAL levels among different types of LN. uNGAL can not be used to monitor the development of the patients with proliferative renal disease.