title: KL-6 concentration in pulmonary epithelial lining fluid is a useful prognostic indicator in patients with acute respiratory distress syndrome.
abstract: BACKGROUND
  KL-6 is a mucin-like glycoprotein expressed on the surface of alveolar type II cells. Elevated concentrations of KL-6 in serum and epithelial lining fluid (ELF) in patients with acute respiratory distress syndrome (ARDS) have been previously reported; however, kinetics and prognostic significance of KL-6 have not been extensively studied. This study was conducted to clarify these points in ARDS patients.
  
  
  METHODS
  Thirty-two patients with ARDS who received mechanical ventilation under intubation were studied for 28 days. ELF and blood were obtained from each patient at multiple time points after the diagnosis of ARDS. ELF was collected using a bronchoscopic microsampling procedure, and ELF and serum KL-6 concentrations were measured.
  
  
  RESULTS
  KL-6 levels in ELF on days 0 to 3 after ARDS diagnosis were significantly higher in nonsurvivors than in survivors, and thereafter, there was no difference in concentrations between the two groups. Serum KL-6 levels did not show statistically significant differences between nonsurvivors and survivors at any time point. When the highest KL-6 levels in ELF and serum sample from each patient were examined, KL-6 levels in both ELF and serum were significantly higher in nonsurvivors than in survivors. The optimal cut-off values were set at 3453 U/mL for ELF and 530 U/mL for serum by receiver operating characteristic (ROC) curve analyses. Patients with KL-6 concentrations in ELF higher than 3453 U/mL or serum concentrations higher than 530 U/mL had significantly lower survival rates up to 90 days after ARDS diagnosis.
  
  
  CONCLUSIONS
  ELF and serum KL-6 concentrations were found to be good indicators of clinical outcome in ARDS patients. Particularly, KL-6 levels in ELF measured during the early period after the diagnosis were useful for predicting prognosis in ARDS patients.
authors.affiliation: Department of Molecular and Internal Medicine, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kondo
authors.forename: Noboru
authors.initials: N
authors.lastname: Hattori
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murai
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Haruta
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hirohashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Tanigawa
authors.forename: Nobuoki
authors.initials: N
authors.lastname: Kohno
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D001999:Bronchoscopy; D005260:Female; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000097:blood / Q000378:metabolism*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000276:immunology* / Q000401:mortality / Q000628:therapy; D020545:Respiratory Mucosa / Q000276:immunology*; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C060192:MUC1 protein, human; D018396:Mucin-1