IL17A and inflammatory bowel disease: Therefore, it is generally recognized that the anti-inflammatory effect of probiotics in IBD is linked to the down-regulation of pro-inflammatory IL-17 cytokine production and upstream Th-17 secreted cytokines (IL-23, TGF-β) and downstream Th-17 secreted cytokines (IL-1β, IL-6, TNF-α, IFNγ, IL-12).