PDGFB and colitis: In animal colitis models, IL-20rb knockout (KO) mice were found to have decreased disease activity index and expression of profibrotic TGF-β and PDGF-b compared to WT(wild-type), supporting the same theory [9, 16]. However, this can be misleading, as IL20rb deficiency leads to the loss of not only IL-24 but also IL-19 and IL-20 signaling, as these cytokines share the same receptor [9, 15].