Krebs Von Den Lungen-6 As A Biomarker for Disease Severity Assessment in Interstitial Lung Disease: A Comprehensive Review

Abstract

Aim: Interstitial lung diseases (ILD) are a group of lung disorders characterized by interstitial lung thickening. Krebs von den Lungen-6 (KL-6) is a molecule that is predominantly expressed by damaged alveolar type II cells and it has been proposed as a potential biomarker of different ILD. Materials & methods: A growing literature about KL-6 has been reviewed and selected to evaluate its role in the clinical management of ILD to predict disease diagnosis, activity, prognosis and treatment response. Results: KL-6 concentrations have been evaluated in fibrotic and granulomatous lung diseases and it was demonstrated to be a biomarker of disease severity useful for clinical follow-up of ILD patients. KL-6 levels differentiated between fibrotic ILD, such as idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis, and nonfibrotic lung disorders, including sarcoidosis and pulmonary alveolar proteinosis. Conclusion: KL-6 is predictive biomarker useful in the clinical management of ILD patients, in particular in patients with severe fibrotic lung disorders.

Keywords:

• hypersensitivity pneumonitis
• idiopathic pulmonary fibrosis
• interstitial lung diseases
• KL-6
• pulmonary fibrosis associated with connective vascular diseases
• sarcoidosis

Author contributions

M d’Alessandro conducted the study. M d’Alessandro, L Bergantini, P Cameli, L Vietri, N Lanzarone, V Alonzi, M Pieroni, RM Refini, P Sestini, F Bonella and E Bargagli helped to define the study objectives. All authors wrote the first draft of the manuscript and critically revised the manuscript and approved its final version.

Acknowledgements

This work was generated within the European Reference Network for Rare Respiratory Diseases (ERN-LUNG).

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.