Novel urinary exosomal biomarkers of acute T cell-mediated rejection in kidney transplant recipients: A cross-sectional study

PLoS One. 2018 Sep 18;13(9):e0204204. doi: 10.1371/journal.pone.0204204. eCollection 2018.

Abstract

Background: Acute rejection is hazardous to graft survival in kidney transplant recipients (KTRs). We aimed to identify novel biomarkers for early diagnosis of acute T cell-mediated rejection (TCMR) in urinary exosomes of KTRs.

Methods: Among 458 graft biopsies enrolled in a cross-sectional multicenter study, 22 patients with stable graft function (STA) who had not shown pathologic abnormality and 25 patients who diagnosed biopsy-proven TCMR were analyzed. We performed proteomic analysis using nano-ultra performance liquid chromatography-tandem mass spectrometry (nano-UPLC-MS/MS) to identify candidate biomarkers for early TCMR diagnosis on urinary exosomes. We confirmed the protein levels of each candidate biomarker by western blot analysis.

Results: A total of 169 urinary exosome proteins were identified by nano-UPLC-MS/MS. Forty-six proteins showed increased expression in STA patients, while 17 proteins were increased in TCMR patients. Among them, we selected five proteins as candidate biomarkers for early diagnosis of TCMR according to significance, degree of quantity variance, and information from the ExoCarta database. We confirmed the proteomic expression levels of five candidate biomarkers by western blot analysis in each patient. Of all candidate biomarkers, tetraspanin-1 and hemopexin were significantly higher in TCMR patients (STA:TCMR ratio = 1:1.8, P = 0.009, and 1:3.5, P = 0.046, respectively).

Conclusions: Tetraspanin-1 and hemopexin were detected in KTR urine and could act as potential diagnostic proteins for TCMR.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomarkers / urine
  • Chromatography, Liquid
  • Cross-Sectional Studies
  • Early Diagnosis
  • Exosomes / metabolism*
  • Female
  • Gene Expression Regulation
  • Graft Rejection / diagnosis*
  • Graft Rejection / immunology
  • Graft Rejection / urine
  • Hemopexin / metabolism
  • Hemopexin / urine*
  • Humans
  • Kidney Transplantation
  • Male
  • Middle Aged
  • Proteomics / methods*
  • Sensitivity and Specificity
  • T-Lymphocytes / immunology*
  • Tandem Mass Spectrometry
  • Tetraspanins / metabolism
  • Tetraspanins / urine*

Substances

  • Biomarkers
  • TSPAN1 protein, human
  • Tetraspanins
  • Hemopexin

Grant support

This work was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), which is funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI13C1232; URL: https://www.khidi.or.kr). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.