Endothelial progenitor cells (
EPC), which are key effectors in the physiologic vascular network, have been described as relevant players in
autoimmune diseases. We previously showed that
EPC frequency may help to identify the presence of
interstitial lung disease (ILD) in
rheumatoid arthritis patients. Given that ILD constitutes the main cause of mortality in
systemic sclerosis (SSc) patients, we aimed to determine the
EPC contribution to the pathogenic processes of vasculopathy and lung
fibrosis in SSc-ILD+.
EPC quantification was performed by flow cytometry on blood from 83 individuals: 21 SSc-ILD+ patients and subjects from comparative groups (20 SSc-ILD- and 21
idiopathic pulmonary fibrosis (IPF) patients and 21 healthy controls (HC)).
EPC were considered as CD34+, CD45low, CD309+, and CD133+. A significant increase in
EPC frequency was found in SSc-ILD+ patients when compared to HC (p < 0.001). SSc-ILD+ patients exhibited a higher
EPC frequency than SSc-ILD- patients (p = 0.012), whereas it was markedly reduced compared to IPF patients (p < 0.001).
EPC frequency was higher in males (p = 0.04) and negatively correlated to SSc duration (p = 0.04) in SSc-ILD+ patients. Our results indicate a role of
EPC in the processes of vasculopathy and lung
fibrosis in SSc-ILD+.
EPC frequency may be considered as a
biomarker of ILD in SSc patients.