title: Serum ratio of soluble triggering receptor expressed on myeloid cells-1 to creatinine is a useful marker of infectious complications in myeloperoxidase-antineutrophil cytoplasmic antibody-associated renal vasculitis.
abstract: BACKGROUND
  The contribution of infections to the mortality of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis patients is important and should induce early and careful control of these events. However, the differentiation of infection from active vasculitis is often difficult. The usefulness of serum-soluble triggering receptor expressed on myeloid cells-1 (TREM-1) for detecting the presence of infectious complications regardless of disease activity was investigated.
  
  
  METHODS
  Soluble TREM-1 in serum obtained from 41 patients with myeloperoxidase (MPO)-ANCA-associated vasculitis was measured by an enzyme-linked immunosorbent assay. Twenty-nine samples were from active vasculitis patients, 27 samples from inactive vasculitis patients without infection and 17 samples from inactive vasculitis patients with infectious complications. Serum-soluble TREM-1 was also measured in 10 patients with acute pyelonephritis and 30 patients with chronic kidney disease (CKD).
  
  
  RESULTS
  There was a significant correlation between serum levels of soluble TREM-1 and serum creatinine levels among all patients (r = 0.554, P < 0.0001). The serum-soluble TREM-1/creatinine ratio was higher in inactive vasculitis patients with infectious complications than in active vasculitis, inactive vasculitis without infection and CKD patients (P = 0.0005, P < 0.0001 and P < 0.0001, respectively), but not significantly different to that in acute pyelonephritis patients. On receiver-operating-characteristic curve analysis, a lower-limit value of 9.40 ng/mg for this ratio had a sensitivity of 84.6% and a specificity of 90.8% in differentiating patients with infection from those without infection.
  
  
  CONCLUSIONS
  The serum ratio of soluble TREM-1 to creatinine may be a useful marker for detection of infectious complications in MPO-ANCA-associated vasculitis.
authors: Department of Nephrology, Tokyo Medical University Ibaraki Medical Center, Ami, Ibaraki, Japan. k-hira@tokyo-med.ac.jp
authors: Kouichi
authors: K
authors: Hirayama
authors: Miho
authors: M
authors: Nagai
authors: Itaru
authors: I
authors: Ebihara
authors: Homare
authors: H
authors: Shimohata
authors: Masaki
authors: M
authors: Kobayashi
authors: Akio
authors: A
authors: Koyama
mesh_terms: D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology*; D001424:Bacterial Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D015415:Biomarkers / Q000097:blood*; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007674:Kidney Diseases / Q000097:blood; D007676:Kidney Failure, Chronic; D008562:Membrane Glycoproteins / Q000097:blood*; D009195:Peroxidase / Q000276:immunology*; D012372:ROC Curve; D011971:Receptors, Immunologic / Q000097:blood*; D012680:Sensitivity and Specificity; D000073871:Triggering Receptor Expressed on Myeloid Cells-1
chemical_list: D015415:Biomarkers; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C408842:TREM1 protein, human; D000073871:Triggering Receptor Expressed on Myeloid Cells-1; D003404:Creatinine; D009195:Peroxidase