Low levels of serum IL-39 are associated with autoimmune thyroid disease

Background Interleukin (IL)-39 is a novel member of IL-12 cytokine family, but its role in autoimmune thyroid diseases (AITD) is unclear. The aim of the present study was to determine serum levels of IL-39 in Hashimoto's thyroiditis (HT) and Graves' disease (GD) patients. Methods A total of 48 patients with HT, 50 patients with GD, and 45 healthy controls (HCs) were recruited for this study. Levels of serum IL-39 were determined by ELISA. Results Compared with HC group, levels of serum IL-39 in patients with HT (p < 0.05) and GD (p < 0.01) were drastically reduced. Among patients with HT, serum IL-39 levels had a positive correlation with white blood cell count (WBC) count and free triiodothyronine level. Among patients with GD, the levels of IL-39 in serum were positively correlated with WBC count and C-reactive protein levels. Conclusions IL-39 may be a new potential predictor for patients with HT and GD.