Imaging and serum biomarkers in connective tissue disease–associated interstitial lung diseases: correlation between lung ultrasound B-lines and KL-6 levels

B-Lines are a new sonographic hallmark of connective tissue disease–associated interstitial lung diseases (CTD-ILDs). Promising data have shown that B-lines are associated with high-resolution CT (HRCT), pulmonary function test and some clinical variables, expanding the armamentarium for screening of ILDs.1 Krebs von den Lungen-6 (KL-6) antigen is a mucin-like, high molecular weight glycoprotein expressed on the surface membrane of alveolar epithelial cells Ⅱ and bronchiolar epithelial cells, and increases following cellular injury and/or regeneration.2 Its role in patients with CTD-ILDs has been studied extensively, indicating KL-6 as a useful biomarker of lung fibrosis and severity of the disease.3 To the best of our knowledge, the correlation between B-lines and serum KL-6 levels in CTD-ILDs has not been reported until now. To investigate the relationship between these two markers, 60 Chinese patients with CTD-ILDs were enrolled. Patients with a history of asthma, chronic …