CD4 and inflammatory bowel disease: In addition, studies have shown that pro-inflammatory cytokines (e.g., IL-12, IL-18, IL-21, IL-23) were significantly increased in the inflamed intestinal mucosa of patients with IBD, while anti-inflammatory cytokines such as TGF-β and IL-10 were remarkably reduced, as well as the absence of immunomodulatory cells such as Treg cells and Foxp3-IL-10+CD4+ T cells (35, 36).