Serum concentrations of KL-6 as a prognostic biomarker in patients with collagenous pneumoconiosis: a retrospective study.

Introduction: KL-6, a pneumocyte derived biomarker, is increased in patients with interstitial lung diseases (ILDs). We aimed to investigate the role of KL-6 as a diagnostic and prognostic biomarker in silica-exposed workers.

Material and Method: We studied 108 silica-exposed subjects and 25 healthy controls. Chest radiography (CXR), pulmonary function tests, inflammatory markers were collected. Progressive massive fibrosis (PMF) was defined according to the ILO classification. KL-6 was measured in serum by ELISA at variable time point during follow up.

Results: PMF was present in 23 subjects. Serum KL-6 levels were significantly higher in subjects with PMF than in controls, exposed workers or simple silicosis (p<0.001). In PMF, serum KL-6 positively correlated with C-reactive protein (CRP) and Erythrocyte sedimentation rate (ERS), and negatively with forced vital capacity (FVC)% predicted. At a cut-off of 436 U/mL, serum KL-6 differentiated exposed workers from PMF with a specificity and sensitivity exceeding 90% (p<0.0001), while a cut-off of 445 U/mL differentiated simple silicosis from PMF (p<0.0001). In the multivariate analysis, serum KL-6 levels were independently associated with risk of fibrosis. Kaplan-Meier confirmed the predictive value of serum KL-6 for PMF over time.

Conclusion: KL-6 appears to be a promising biomarker for the occurrence and progression of PMF in silica-exposed workers.

Publication History

Article published online:
18 March 2025