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Introduction Systemic sclerosis (SSc) is a rare autoimmune disease characterized by early vasculopathy and progressive fibrosis, with interstitial lung disease (SSc-ILD) being the leading cause of SSc-related mortality. Vascular injury and defective repair mechanisms are increasingly recognized as contributors to ILD pathogenesis in SSc. Angiogenic T cells (Tang; CD3+, CD31+, CXCR4+) are a T cell subgroup that mediate endothelial repair through tissue migration and secretion of proangiogenic factors (VEGF, IL-8). Tang cells have been implicated in autoimmune vasculopathies, yet their role in SSc and SSc-ILD remains poorly defined. Given the vascular contribution to SSc-ILD, altered Tang biology may represent both a mechanistic contributor and a potential biomarker of disease severity. We, therefore, aimed to determine Tang levels in SSc-ILD patients, their clinical associations, and their presence in SSc lung tissue.Material and Methods 83 SSc patients (2013 ACR/EULAR criteria), and 23 age- and sex-matched healthy controls (HC) were included. Clinical, serological, and pulmonary function data were collected. Flow cytometry was used to quantify circulating Tang subsets (total, CD4+, CD8+) in previously stored PBMCs. Nailfold capillaroscopy was carried out and assessed based on the EULAR SG MC/RD evaluation system. Pulmonary function tests and autoantibody profiles were recorded and assessed. Serum IL-8 and VEGF levels were measured by ELISA. Preliminary immunohistochemistry (CD3, CD31, CXCR4) was performed on explanted lung tissue from SSc-ILD patients.Results No differences in clinical characteristics were observed between the studied groups. Total, CD4+, and CD8+ Tang proportions were significantly reduced in SSc-ILD compared to SSc without ILD (p<0.001) and HC (p=0.042), but not between SSc without ILD and HC. Tang levels correlated positively with diffusion capacity of the lung (DLCO; total Tang: p=0.007; CD4+ Tang: p=0.021) and inversely with age (p<0.001). The ANA-positive group with predominantly anti-RNA polymerase III (ARA) had lower Tang proportions compared to anti-centromere positive patients. Higher Tang levels were observed in patients with an early nailfold capillaroscopy pattern versus active/late (p=0.046). Serum IL-8 and VEGF did not correlate with Tang levels. Preliminary lung immunohistochemistry revealed increased presence of Tang cells in SSc-ILD tissue compared to non-ILD controls.Conclusions Circulating Tang cells are selectively decreased in SSc-ILD, and correlate with impaired pulmonary function, and associate with ARA-positivity and early scleroderma patterns on nailfold capillaroscopy. Preliminary immunohistochemistry findings suggest an increased Tang presence in the SSc lung, supporting their potential involvement in ILD pathogenesis. These results highlight Tang cells as potential target cells and warrant further studies into their role in SSc-ILD.Abstract P.100 Figure 1Abstract P.100 Table 1Demographic and elinical characteristies of SSe patients and healthy controls