IL17A and Crohn disease: Interestingly, while IL-17 inhibitors may exacerbate or induce IBD, inhibitors targeting IL-12/23 or IL-23 alone (e.g., ustekinumab, risankizumab) have been approved for both psoriasis and Crohn’s disease, suggesting that upstream modulation of the Th17 axis may be less disruptive to gut homeostasis.