Idiopathic pulmonary fibrosis (IPF) and non-specific interstitial pneumonia (NSIP) are the most frequent idiopathic interstitial pneumonias. The aim of this study was to evaluate concentrations of calgranulin B and Krebs von den Lungen 6 (KL-6) in bronchoalveolar lavage (BAL) fluid of patients with IPF and idiopathic NSIP (i-NSIP) with fibrotic pattern. Thirty patients with IPF (68.73 ± 8.63 years), 30 with i-NSIP (68.33 ± 7.45 years), and healthy controls were included in the study. Calgranulin B and KL-6 both proved to be significantly higher in BAL of IPF and i-NSIP patients than in healthy controls (p < 0.05). Calgranulin B showed several significant correlations with functional parameters (oxygen demand at rest, 6-min walking test (6MWT), and PFTs); KL-6 was correlated with oxygen demand at rest and during 6MWT. Patients with higher concentrations of both biomarkers (> 75th percentile) had more advanced disease with lower values of FEV1%, FVC%, RV%, TLC%, DLCO% of predicted, distance walked in 6MWT, and BAL neutrophil percentage. Calgranulin B and KL-6 in BAL proved to be reliable biomarkers of IPF and i-NSIP and to have prognostic meaning, discriminating severe and advanced patients. The combination of the two biomarkers can facilitate the stratification of severity.
Keywords: KL-6; biomarkers; bronchoalveolar lavage; calgranulin B; idiopathic pulmonary fibrosis; non-specific interstitial pneumonia.