Angiogenic T Cells: Potential Biomarkers for the Early Diagnosis of Interstitial Lung Disease in Autoimmune Diseases?

(1) Background: We explored, for the first time, the contribution of angiogenic T cells (TAng) in interstitial lung disease associated to autoimmune disease (AD-ILD + ) as potential biomarkers of the disease, evaluating their role in the underlying vasculopathy and lung fibrosis. Additionally, the relationship of TAng with clinical manifestations and cellular and molecular endothelial dysfunction-related biomarkers was assessed. (2) Methods: We included 57 AD-ILD + patients (21 with rheumatoid arthritis (RA)-ILD + , 21 with systemic sclerosis (SSc)-ILD + and 15 with other AD-ILD + ) and three comparative groups: 45 AD-ILD - patients (25 RA-ILD - and 20 SSc-ILD - ); 21 idiopathic pulmonary fibrosis (IPF) patients; 21 healthy controls (HC). TAng were considered as CD3 + CD184 + CD31 + by flow cytometry. (3) Results: A similar TAng frequency was found between AD-ILD + and IPF, being in both cases lower than that observed in AD-ILD - and HC. A lower TAng frequency was associated with negative Scl-70 status and lower FEV1/FVC ratio in SSc-ILD + , as well as with men in RA-ILD + and non-specific interstitial pneumonia radiological pattern in other AD-ILD + . No relationship between TAng and endothelial progenitor cells, endothelial cells and vascular endothelial growth factor gene expression and protein levels was disclosed. (4) Conclusions: Our findings suggest TAng as potential biomarkers for the early diagnosis of ILD in AD.