title: High serum and urine neutrophil gelatinase-associated lipocalin levels are independent predictors of renal progression in patients with immunoglobulin A nephropathy.
abstract: OBJECTIVE
  Tubulointerstitial injury plays an important role in the progression of immunoglobulin A nephropathy (IgAN), and neutrophil gelatinase-associated lipocalin (NGAL) is among the most sensitive tubular biomarkers. We investigated whether serum or urine NGAL predicts prognosis in patients with IgAN.
  
  
  METHODS
  The present study enrolled patients with biopsy-proven IgAN from January 2005 to December 2010, whose serum and urine samples at the time of kidney biopsy were preserved by freezing. We retrospectively reviewed patient clinical data and followed patients until October 2012. Serum and urine NGAL levels were measured using an enzyme-linked immunosorbent assay kit. Renal progression was defined as an estimated glomerular filtration rate decline by > 50% or progression to end-stage renal disease.
  
  
  RESULTS
  There were 121 patients enrolled in this study. During the median follow-up period of 41.49 months, renal progression was found in nine patients (7.4%). Serum or urine NGAL alone could not predict renal progression; however, when serum and urine NGAL levels were combined, belonging to the high NGAL group independently predicted renal progression (hazard ratio [HR], 5.56; 95% confidence interval [CI], 1.42 to 21.73; p = 0.014), along with tubular damage graded according to the Oxford classification as T2 (HR, 8.79; 95% CI, 2.01 to 38.51; p = 0.004). In addition, a Kaplan-Meier curve of renal survival showed significantly higher renal progression in patients in the high NGAL group (log rank, p = 0.004).
  
  
  CONCLUSIONS
  In patients with IgAN, high serum and urine NGAL levels at the time of kidney biopsy predict renal progression.
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Harin
authors.initials: H
authors.lastname: Rhee
authors.affiliation: Biomedical Research Institute, Pusan National University Hospital, Busan, Korea. ; Department of Pathology, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Nari
authors.initials: N
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Byung Yun
authors.initials: BY
authors.lastname: Yang
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Il Young
authors.initials: IY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Sang Heon
authors.initials: SH
authors.lastname: Song
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Soo Bong
authors.initials: SB
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Ihm Soo
authors.initials: IS
authors.lastname: Kwak
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea. ; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Seong
mesh_terms: D000209:Acute-Phase Proteins / Q000652:urine*; D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001706:Biopsy; D016009:Chi-Square Distribution; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000652:urine*; D006801:Humans; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood* / Q000652:urine*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011518:Proto-Oncogene Proteins / Q000097:blood* / Q000652:urine*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins
keywords: Glomerulonephritis, IGA; Prognosis; Serum neutrophil gelatinase-associated lipocalin; Tubular biomarker; Urine neutrophil gelatinase-associated lipocalin