Angiotensin-converting enzyme 1 gene polymorphisms in patients with systemic sclerosis-associated interstitial lung disease: a single centre retrospective observational study.

Angiotensin-converting enzyme (ACE) 1 gene polymorphisms have been associated with vascular permeability, alveolar endothelial dysfunction and fibroblast proliferation and have been studied in pulmonary diseases such as COPD and idiopathic pulmonary fibrosis. Similar mechanisms of ACE 1 polymorphisms have been seen in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD). We are presenting a retrospective observational study in patients with SSc-ILD and analysing the association of ACE 1 gene polymorphisms (DD, II and ID) with the features of SSc, changes in pulmonary function tests (PFTs) and lung HRCT over three different periods of time (at the time of the diagnosis, 5 and 10 years after the diagnosis). The aim of the study was to determine whether ACE 1 gene polymorphisms have an effect on the severity of SSc-ILD. We found no statistically significant differences in the development and severity of SSc-ILD and changes in PFTs between subgroups of ACE 1 gene polymorphism over the analysed periods (at the time of diagnosis HRCT changes p = 0.270, FEV1 p = 0.483, FVC p = 0.497, DLco p = 0.807, after 5 years HRCT changes p = 0.163, FEV1 p = 0.551, FVC p = 0.362, DLco p = 0.620 and 10 years of follow-up HRCT changes p = 0.853, FEV1 p = 0.589, FVC p = 0.328, DLco p = 0.992). However, patients with the ID genotype showed a significant reduction in FEV1 after 10 years of follow-up in comparison to baseline levels (91.0 (IR 80.0-105.0) at the time of diagnosis and 84.0 (IR 69.0-99.0) after 10 years, p = 0.014). Our study suggests that ACE 1 gene polymorphisms do not have a role in the severity of SSc-ILD. Further studies are needed to explain the exact role of ACE 1 gene polymorphisms in SSc-ILD and SSc in general.