Background: IL-37, member of the IL-1 family, is a natural suppressor of immune and inflammatory responses. Increased serum IL-37 levels were observed in several autoimmune diseases, including Graves disease. No data on TH are available from the literature.
Materials and methods: We enrolled 45 euthyroid HT patients (5 M e 40 F, mean age 38.5±12.6) and 50 age- and sex-matched healthy controls. None was on LT-4 therapy. Smokers, subjects with kidney failure, history of cancer or autoimmune, inflammatory and infection comorbidities were excluded. Serum IL-37 levels were measured by ELISA (kit IL-37 DuoSet Elisa, R&D System, Minneapolis, USA; minimum detectable dose 10 pg/ml). Specific serum tests, such as d-ROMs (derived Reactive Oxygen Metabolites) test and BAP (Biological Antioxidant Potential) test (Diacron International, Italy), were performed in all subjects to investigate the changes in oxidative balance, and AGEs (Advanced Glycation End Products) were determined as a specific marker of oxidative stress.
Results: IL-37 levels were significantly higher in TH (mean± S.D.: 999.59±1064.93 pg/ml) than in controls (448.02±498.96 pg/ml; P=0.018). In both groups, these values correlated negatively with age (TH, RS=−0.377 P=0.016; controls, RS=−0.404; P=0.06) and were tendentially higher in men than in women (P=0.063). Furthermore, there was a positive correlation between serum IL-37 levels and TSH, statistically significant in TH (RS=0.412 P=0.008; in controls, RS=0.418; P=0.053). The regression analysis showed a significant positive association between IL-37 and d-ROMs (P=0.029) and AGEs (P=0.014): if serum d-ROMs and AGEs levels increased, serum IL-37 levels also increased. A significant direct correlation between serum IL-37 levels and AGEs was also observed (RS=0.578; P=0.006).
Conclusion: Serum IL-37 levels were significantly increased in TH patients and correlated with oxidative stress parameters. Given the anti-inflammatory properties, IL-37 could be an innovative research strategy for TH pathogenesis and therapy.
20 - 23 May 2017
European Society of Endocrinology