Thymic stromal lymphopoietin in systemic sclerosis interstitial lung disease: a pilot study.

Objectives: Systemic sclerosis (SSc) is an autoimmune disease, characterised by microvascular alterations, dysregulation of immune system and fibrosis. The most important complication is interstitial lung disease (ILD). The aim of this study was to evaluate serum levels of thymic stromal lymphopoietin (TSLP) in SSc patients and healthy controls (HC). The secondary aim was to correlate TSLP with skin fibrosis and extension of ILD.

Methods: 75 SSc patients and 20 HC were enrolled and serum TSLP levels were measured in both cohorts. Pulmonary function tests (PFTs), high-resolution computed tomography (HRCT) and exhaled fraction of nitric oxide (FeNO) were assessed in SSc patients. A visual semi-quantitative staging system, tomographic fibrosis score (TFS), was used to assess SSc-ILD.

Results: Serum levels of TSLP were higher in SSc patients than HC. A positive correlation between TSLP and mRSS was observed (r=0.409, p<0.001) and a negative correlation was found between TSLP and FVC (r=-0.356, p<0.01). Serum TSLP was significantly higher in SSc patients with Type 2 inflammation than patients without Type 2 inflammation [172 pg/ml (IQR 154.67;224.67) vs. 150 pg/ml (IQR 110;210.33), p<0.05]. The median value of serum TSLP was significantly higher in SSc patients with TFS ≥ 5% than SSc patients with TFS <5% [216.67 pg/ml (IQR 172;298.67) vs 140.67 pg/ml (IQR 122;166.67), p<0.001).

Conclusions: In conclusion, TSLP might have a key role in ILD and skin fibrosis.