Low serum interleukin-38 levels in patients with Graves' disease and Hashimoto's thyroiditis.

BACKGROUND: Autoimmune thyroid disease (AITD) mainly includes Graves' disease (GD) and Hashimoto's thyroiditis (HT), which is caused by individual genetics, autoimmune dysfunction, and a variety of external environmental factors. Interleukin (IL)-38 is involved in a wide range of autoimmune diseases, but little is known about IL-38 expression in AITD. METHODS: Fifty patients with GD, 50 with HT, and 50 healthy controls (HC) were enrolled in this study. Basic information of the participants was obtained through a physical examination. Immunological data were obtained by an automatic chemiluminescence immunoanalyzer. C-reactive protein (CRP) concentrations and the white blood cell count were measured. Serum IL-38 levels were determined by an enzyme-linked immunosorbent assay. RESULTS: Serum IL-38 levels were significantly lower in the GD and HT groups than in the HC group (both p < 0.01). Serum CRP concentrations were significantly lower in the HT group than in the HC group (p < 0.05). Receiver operating characteristic curve analysis showed that the area under the curve was 0.7736 (p < 0.01) for IL-38 and 0.7972 (p < 0.01) for IL-38 combined with CRP in the GD group. In the HT group, the area under the curve was 0.7276 (p < 0.01) for IL-38 and 0.7300 for IL-38 combined with CRP (p < 0.01). CONCLUSIONS: The results suggest that serum IL-38 level is a potential new diagnostic biomarker in patients with GD and HT.