E-Selectin, ICAM-1, and ET-1 Biomarkers Address the Concern of the Challenging Diagnosis of Interstitial Lung Disease in Patients with Autoimmune Diseases.

Interstitial lung disease (ILD) constitutes the most critical comorbidity in autoimmune diseases (ADs) and its early diagnosis remains a challenge for clinicians. Accordingly, we evaluated whether E-selectin, ICAM-1, and ET-1, key molecules in endothelial damage, could be useful biomarkers for the detection of AD-ILD. We recruited patients with rheumatoid arthritis (RA)-ILD ( = 21) and systemic sclerosis (SSc)-ILD ( = 21). We included comparison groups of patients: RA-ILD ( = 25), SSc-ILD ( = 20), and idiopathic pulmonary fibrosis (IPF) ( = 21). Serum levels of these proteins were determined by ELISA. E-selectin, ICAM-1, and ET-1 serum levels were increased in RA-ILD and IPF patients in comparison to RA-ILD patients. Additionally, SSc-ILD and IPF patients exhibited higher ICAM-1 levels than those with SSc-ILD. The ability of E-selectin, ICAM-1, and ET-1 to discriminate RA-ILD from RA-ILD patients, and ICAM-1 to distinguish SSc-ILD from SSc-ILD patients was confirmed using ROC curve analysis. Furthermore, elevated levels of ET-1 and E-selectin correlated with lung function decline in RA-ILD and SSc-ILD patients, respectively. In conclusion, our findings support the relevant role of E-selectin, ICAM-1, and ET-1 in RA-ILD patients as well as of ICAM-1 in SSc-ILD patients, constituting potential screening blood biomarkers of ILD in AD. Moreover, this study suggests ET-1 and E-selectin as possible indicators of worsening lung function in RA-ILD and SSc-ILD patients, respectively.