Abstract
Background: CC16 is a protein secreted by the bronchiolar epithelial cells “club” that has been reported decreased in airways diseases and acute respiratory distress syndrome. In interstitial lung diseases (ILD) including IPF, studies on circulating levels of CC16 are scanty.
Objective: To determine serum levels of CC16 in interstitial lung diseases
Methods: A cross-sectional study was performed in 3 groups: IPF (n=85), chronic hypersensitivity pneumonitis (cHP; n=85), and ILD associated to rheumatoid arthritis and Sjogren (ILD/RAS; n=85) and in 30 healthy subjects. CC16 was determined by ELISA and its localization in IPF lungs by immunohistochemistry. ROC analysis was used to evaluate its possible role as biomarker for the differential diagnosis of IPF with the other diseases.
Results: CC16 was significantly elevated in IPF compared to the other two diseases (FPI: 31.9+11.2 ng/ml versus cHP: 26.6+15 ng/ml), versus ILD/RAS (22.4+12.6 ng/ml), and versus controls (10.0+7.7 ng/ml) ANOVA p <0.0001. Sensitivity and specificity cutoff (41 ng/mL) was 24% and 90%, respectively, PPV 56% and NPV 69%. The AUC for IPF versus the other diseases was 0.68 (95% CI: 0.613-0.745). CC16 was over-expressed in IPF lungs and localized in bronchiolar and aberrant alveolar epithelial cells.
Conclusions: These findings indicate that serum levels of CC16 are increased in patients with IPF compared with other ILDs suggesting a role in its pathogenesis. However, its accuracy as biomarker for differential diagnosis does not seem adequate.
- Copyright ©the authors 2016
