Backgrounds: Systemic sclerosis (SSc), a disease that causes fibrosis in various organs, can develop pulmonary hypertension (PH) due to lung fibrosis. We found that IL-18 induced pulmonary hypertension in a hypoxia model mouse. The association between IL-18 and ferritin in patients with viral infections has recently been reported. However, the roles of IL-18 and ferritin in SSc patients with PH are not fully elucidated. The purpose of this study is to investigate the relationships among IL-18, ferritin, and PH in SSc patients. Methods: We enrolled 18 SSc patients who visited our hospital between January 2014 and June 2016 and presented tricuspid regurgitation jet velocity >2.5 m/s in this retrospective observational study. We measured the serum levels of ferritin and IL-18, and the parameters of right heart catheterization (RHC). Results: Mean age of the patients was 66 y.o. and 16 patients were female. Average mean pulmonary artery pressure were 24.0 ± 3.5 mmHg and pulmonary vascular resistance index (PVRI) 4.6 ± 1.9 wood. Serum IL-18 levels were 288.4 ± 49.8 pg/mL and serum ferritin levels were 47.0 ± 25.9 ng/mL. levels of serum IL-18 and serum ferritin were correlated with PVRI respectively (IL-18 r = 0.674, ferritin r = 0.734). In addition, serum IL-18 was correlated with serum ferritin (r = 0.481). Conclusion: In SSc patients, IL-18 as well as ferritin was associated with PH.
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