TNF and inflammatory bowel disease: To explore the underlying mechanisms responsible for the regulation of IL-24 synthesis we investigated the effect of different IBD-related factors, including IL-1β, IL-17, TNF-α, TGF-β, H2O2 and LPS [33] on the IL-24 expression in immune cells derived from peripheral blood (PBMCs) or from the lamina propria (LPMCs) (Fig. 1d–e).