Background The pathogenesis of pulmonary fibrosis is not fully understood and it is thought to develop secondary to inflammation. The main cause of pulmonary fibrosis is considered to be interstitial lung disease (ILD), which can be associted with connective tissue disorders (CTD).

Objectives The aim of this study was to investigate serum GDF-15 and TGF-β levels in patients with diagnosis of CTD associated with ILD.

Methods A total of 103 adult patients (19 rheumatoid arthritis, 18 Sjögren's syndrome, 32 systemic sclerosis, 3 systemic lupus erythematosus and 31 healthy controls) were included in the study. Pregnant, acute coronary syndrome, previous myocardial infarction and/or stroke history, heart failure and malignancy were excluded. Serum GDF-15 and TGF-β levels were studied by ELISA method in peripheral blood samples.

Results There were 44 patients with CTD-ILD, 28 patients without ILD and 31 healthy controls. The age and gender distributions of participants in all three groups were not different. Serum TGF-β and GDF-15 levels in patients with CTD-ILD and CTD without ILD were significantly higher than healthy controls (respectively, 3.05±0.26, 3.05±0.22, 1.39±0.33 pg/ml, p<0.001 for TGF-β and 1.17±0.17, 1.12±0.05, 0.95±0.21 pg/ml, p<0.001 for GDF-15). There were no statistically different from patients with ILD and without ILD for both TGF-β (p:0.864) and GDF-15 levels (p:0.146) in CTD. Also, GDF-15 and TGF-β levels of patients with systemic sclerosis were not different from other CTD's.

Conclusions Our findings indicate that TGF-β and GDF-15 are increased in CTD patients but, they are not a specific markers for CTD-ILD

Disclosure of Interest None declared