Serum KL-6 as a biomarker for interstitial lung diseases in a clinical setting: application of a fully automated immunoassay

Abstract

Rationale: KL-6, high-molecular weight mucin, expressed on type II pneumocytes, is elevated in several interstitial lung diseases (ILD). KL-6 has not been validated in Caucasians yet. The aim of this study was to measure KL-6 serum levels in a large cohort of patients with common ILDs such as idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP) and to investigate its role to assess disease severity. Patients and Methods: 254 consecutive patients (129 IPF, 125 NSIP) and 40 healthy controls were retrospectively studied. ILD diagnosis was made according to the ATS/ERS criteria 2013. KL-6 was measured using the Lumipulse®G KL-6 Chemiluminescent enzyme immunoassay (Fujirebio Europe, Belgium). KL-6 levels were correlated with clinical and functional variables at baseline. Results: Serum KL-6 levels were significantly higher in ILD patients than controls (1801.2±103.5 U/mL vs 252.9±24.2; p Conclusions: Serum KL-6 level is a valuable diagnostic marker for ILD but not for IPF discrimination. KL-6 may be also useful to assess the disease severity in a routine clinical setting.