KL-6 concentration in pulmonary epithelial lining fluid is a useful prognostic indicator in patients with acute respiratory distress syndrome

Tomohiro Kondo,Yoshinori Haruta,Hiroshi Murai,Koichi Tanigawa,Nobuoki Kohno,Nobuyuki Hirohashi,Nobuhisa Ishikawa,Noboru Hattori

doi:10.1186/1465-9921-12-32

Tomohiro Kondo, Yoshinori Haruta + Show 6 more

Open Access

https://doi.org/10.1186/1465-9921-12-32

Copy DOI

Abstract

BackgroundKL-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.MethodsThirty-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.ResultsKL-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.ConclusionsELF 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.

Highlights

KL-6 is a mucin-like glycoprotein expressed on the surface of alveolar type II cells
The patients with interstitial pneumonia, hypersensitivity pneumonia, and druginduced pneumonia were confirmed to have had stable respiratory condition before the onset of acute respiratory distress syndrome (ARDS) and the apparent superimposition of pulmonary infection in these three patients was denied by the analysis of bronchoalveolar lavage fluid (BALF)
KL-6 levels in epithelial lining fluid (ELF) and serum samples of survivors and nonsurvivors The kinetics of KL-6 levels in ELF and serum samples were first compared between the survivors and nonsurvivors

Summary

Introduction

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; kinetics and prognostic significance of KL-6 have not been extensively studied. Acute respiratory distress syndrome (ARDS) is characterized by the influx of protein-rich edema fluid into air spaces because of the increased permeability of the alveolar-capillary barrier [1,2]. Previous studies have demonstrated that serum levels of KL-6 are elevated in a variety of interstitial lung diseases that are characterized by alveolar epithelial cell damage [12,14,15,16,17,18,19,20]. Because serum levels of KL-6 have been shown to be correlated with indices of alveolar-capillary permeability [15], elevated levels of circulating KL-6 are believed to be associated with its increased leakage from the alveolar space into the circulation

Methods

Results

Conclusion