title: [Expression of urinary neutrophil gelatinase-associated lipocalin and its clinical significance in children with idiopathic nephrotic syndrome].
abstract: OBJECTIVE
  To investigate the urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration in children with idiopathic nephrotic syndrome (INS) and its clinical significance.
  
  
  METHODS
  Thirty-four children newly diagnosed with INS received oral prednisone for 4 weeks. Patients whose urinary protein did not become negative were classified as steroid-resistant nephrotic syndrome (SRNS) group, while those whose urinary protein did become negative were classified as steroid-sensitive nephrotic syndrome (SSNS) group. Morning midstream urine specimens were collected from all patients before use of prednisone and after 1, 2, 3, and 4 weeks of treatment with prednisone. Enzyme-linked immunosorbent assay was used to measure the urinary NGAL concentration. Meanwhile, urinary creatinine (Cr) concentration was measured, and urinary NGAL concentration in a single urine collection was adjusted according to the urinary Cr excretion. The two groups were compared in terms of urinary NGAL/Cr ratio.
  
  
  RESULTS
  Compared with the SRNS group, the SSNS group had significantly decreased urinary NGAL/Cr ratios after 3 and 4 weeks of prednisone treatment (P < 0.05). Compared with the SRNS group, the SSNS group had a significantly decreased urinary β2-MG/Cr ratio after 4 weeks of prednisone treatment (P < 0.05). In both groups, urinary NGAL/Cr ratio was positively correlated with urinary protein/Cr ratio (r = 0.510, P < 0.01). The results of ROC curve analysis showed when diagnostic cut-off point of urinary NGAL/Cr was 0.043 by 3 weeks after treatment, sensitivity and specificity achieved 100% and 79.2% respectively.
  
  
  CONCLUSIONS
  Urinary NGAL/Cr ratio remains high in children with SRNS, while this ratio decreases gradually during prednisone treatment in children with SSNS, and it falls ahead of urinary β2-MG/Cr ratio. These results suggest that dynamic monitoring of urinary NGAL/Cr ratio is useful for early judgment of response to prednisone in patients with INS.
authors.affiliation: Children's Medical Center, Second Xiangya Hospital of Central South University, Changsha 410011, China. heqn@163.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Xia
authors.forename: Qing-Nan
authors.initials: QN
authors.lastname: He
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Li
authors.forename: Lan-Jun
authors.initials: LJ
authors.lastname: Shuai
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Chen
authors.forename: Zhu-Wen
authors.initials: ZW
authors.lastname: Yi
mesh_terms: D000209:Acute-Phase Proteins / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D000071068:Lipocalin-2; D054834:Lipocalins / Q000652:urine*; D008297:Male; D009404:Nephrotic Syndrome / Q000188:drug therapy / Q000652:urine*; D011241:Prednisone / Q000627:therapeutic use; D011518:Proto-Oncogene Proteins / Q000652:urine*; D001613:beta 2-Microglobulin / Q000652:urine
chemical_list: D000209:Acute-Phase Proteins; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D001613:beta 2-Microglobulin; D003404:Creatinine; D011241:Prednisone