title: Discovery and validation of a molecular signature for the noninvasive diagnosis of human renal allograft fibrosis.
abstract: BACKGROUND
  Tubulointerstitial fibrosis (fibrosis), a histologic feature associated with a failing kidney allograft, is diagnosed using the invasive allograft biopsy. A noninvasive diagnostic test for fibrosis may help improve allograft outcome.
  
  
  METHODS
  We obtained 114 urine specimens from 114 renal allograft recipients: 48 from 48 recipients with fibrosis in their biopsy results and 66 from 66 recipients with normal biopsy results. Levels of messenger RNAs (mRNAs) in urinary cells were measured using kinetic, quantitative polymerase chain reaction assays, and the levels were related to allograft diagnosis. A discovery set of 76 recipients (32 with allograft fibrosis and 44 with normal biopsy results) was used to develop a diagnostic signature, and an independent validation set of 38 recipients (16 with allograft fibrosis and 22 with normal biopsy results) was used to validate the signature.
  
  
  RESULTS
  In the discovery set, urinary cell levels of the following mRNAs were significantly associated with the presence of allograft fibrosis: vimentin (P<0.0001, logistic regression model), hepatocyte growth factor (P<0.0001), α-smooth muscle actin (P<0.0001), fibronectin 1 (P<0.0001), perforin (P=0.0002), plasminogen activator inhibitor 1 (P=0.0002), transforming growth factor β1 (P=0.0004), tissue inhibitor of metalloproteinase 1 (P=0.0009), granzyme B (P=0.0009), fibroblast-specific protein 1 (P=0.006), CD103 (P=0.02), and collagen 1A1 (P=0.04). A four-gene model composed of the levels of mRNA for vimentin, NKCC2, and E-cadherin and of 18S ribosomal RNA provided the most accurate, parsimonious diagnostic model of allograft fibrosis with a sensitivity of 93.8% and a specificity of 84.1% (P<0.0001). In the independent validation set, this same model predicted the presence of allograft fibrosis with a sensitivity of 77.3% and a specificity of 87.5% (P<0.0001).
  
  
  CONCLUSIONS
  Measurement of mRNAs in urinary cells may offer a noninvasive means of diagnosing fibrosis in human renal allografts.
authors.affiliation: Department of Kidney Transplantation, Necker Hospital, Assistance Publique Hôpitaux de Paris-APHP, Université Paris Descartes Sorbonne Paris Cité, Paris, France.
authors.forename: Dany
authors.initials: D
authors.lastname: Anglicheau
authors.forename: Thangamani
authors.initials: T
authors.lastname: Muthukumar
authors.forename: Aurélie
authors.initials: A
authors.lastname: Hummel
authors.forename: Ruchuang
authors.initials: R
authors.lastname: Ding
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Sharma
authors.forename: Darshana
authors.initials: D
authors.lastname: Dadhania
authors.forename: Surya V
authors.initials: SV
authors.lastname: Seshan
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Schwartz
authors.forename: Manikkam
authors.initials: M
authors.lastname: Suthanthiran
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D001706:Biopsy; D015820:Cadherins / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D005355:Fibrosis; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology*; D007674:Kidney Diseases / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000652:urine; D016030:Kidney Transplantation / Q000473:pathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011183:Postoperative Complications / Q000175:diagnosis* / Q000473:pathology / Q000652:urine; D012333:RNA, Messenger / Q000652:urine*; D012337:RNA, Ribosomal, 18S / Q000652:urine; D012372:ROC Curve; D012680:Sensitivity and Specificity; D028021:Sodium-Potassium-Chloride Symporters / Q000652:urine; D064466:Solute Carrier Family 12, Member 1; D014746:Vimentin / Q000652:urine
chemical_list: D015415:Biomarkers; D015820:Cadherins; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; C578714:SLC12A1 protein, human; D028021:Sodium-Potassium-Chloride Symporters; D064466:Solute Carrier Family 12, Member 1; D014746:Vimentin