title: Poor histological lesions in IgA nephropathy may be reflected in blood and urine peptide profiling.
abstract: BACKGROUND
  IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, leading to renal failure in 15% to 40% of cases. IgAN is diagnosed by renal biopsy, an invasive method that is not risk-free. We used blood and urine peptide profiles as a noninvasive method of linking IgAN-associated changes with histological lesions by Oxford classification.
  
  
  METHODS
  We prospectively studied 19 patients with biopsy-proven IgAN and 14 healthy subjects from 2006 to 2009, excluding subjects with crescentic glomerulonephritis and collecting clinical and biochemical data at the time of diagnosis and during follow-up (24 months). Histological lesions were evaluated by Oxford classification. Proteomic analysis was performed by combining magnetic bead (MB) technology and mass spectrometry (MALDI-TOF MS) to obtain peptide profiles. Doubling of serum creatinine was considered a variable of poor renal prognosis.
  
  
  RESULTS
  We identified 55 peptides-13 in serum, 26 in plasma, and 16 in urine-that differentiated IgAN patients from healthy subjects. A significant association was noted between serum/plasma and urine peptides and histological findings-ie, tubulointerstitial damage, segmental glomerulosclerosis, and endocapillary injury.
  
  
  CONCLUSIONS
  In patients with IgAN, the use of noninvasive approaches, such as blood and urine proteomics, can provide valuable information beyond that of standard diagnostic techniques, allowing us to identify blood and urine peptide profiles that are associated with poor histological lesions in IgAN patients.
authors.forename: Fredzzia
authors.initials: F
authors.lastname: Graterol
authors.forename: Maribel
authors.initials: M
authors.lastname: Navarro-Muñoz
authors.forename: Meritxell
authors.initials: M
authors.lastname: Ibernon
authors.forename: Dolores
authors.initials: D
authors.lastname: López
authors.forename: Maria-Isabel
authors.initials: MI
authors.lastname: Troya
authors.forename: Vanessa
authors.initials: V
authors.lastname: Pérez
authors.forename: Josep
authors.initials: J
authors.lastname: Bonet
authors.forename: Ramón
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000175:diagnosis / Q000652:urine*; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood* / Q000652:urine*; D011446:Prospective Studies; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D016482:Urinalysis / Q000379:methods
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments