Supplementary Material for: Interleukin-1β as a Predictor of Glucocorticoid Response in Ulcerative Colitis

Background/Aim: Currently, there are no established biomarkers to differentiate between glucocorticoid (GC)-resistant and GC-sensitive ulcerative colitis (UC); however, interleukin (IL)-1β could be one such candidate biomarker. The aim of this study was to investigate whether mucosally expressed IL-1β could predict the response to GC in patients with UC. Methods: A total of 27 mucosal tissue samples from 10 patients with GC-resistant UC (GC-resistant group), 9 patients with GC-sensitive UC (GC-sensitive group), and 8 control patients (control group) were analyzed by qRT-PCR for the expression of IL-1β, GC receptor α (GRα), GRβ, and other inflammatory mediators. Rachmilewitz endoscopic index (REI) between the GC-resistant and GC-sensitive groups was matched to avoid any potential influence of inflammation. Results: The REI did not significantly differ between the GC-resistant and GC-sensitive groups. Mucosally expressed IL-1β levels in the GC-resistant group were significantly higher than those in the GC-sensitive group. However, there were no significant differences in the expression levels of GRα, GRβ, and other inflammatory mediators between the 2 groups. We could distinguish between the GC-resistant and GC-sensitive groups with a sensitivity of 90.0% and specificity of 77.8% based on mucosally expressed IL-1β. Conclusions: Mucosally expressed IL-1β can be used as a predictor of GC response in patients with UC.