Immune-microbe interactions in pediatric ulcerative colitis: clinical features, pathogenesis, and novel targeted therapeutic strategies.

Pediatric ulcerative colitis (PUC) is a chronic, immune-mediated inflammatory disease that exhibits different clinical characteristics and pathogenesis from those in adults. PUC is more severe and has a wider lesion range. The main manifestations include diarrhea, bloody stool, abdominal pain, and tenesmus, as well as systemic symptoms such as weight loss and anemia. However, the current treatment regimens for children with PUC cannot meet the increasing clinical cure demands, which is due to insufficient understanding of the pathogenesis of PUC. The pathogenesis of PUC is believed to be caused by the interaction of genetic and environmental factors, leading to an excessive and dysregulated immune response of the intestinal mucosa to microorganisms. This review summarizes the epithelial barrier defect, excessive innate immune activation, adaptive immune dysregulation, and associated cytokine dysregulation in the pathogenesis of PUC. Moreover, the potential therapeutic effects of new immunomodulatory therapies, including microbial therapy and anti-integrin biological agents, on PUC are summarized. The aim is to deepen the understanding of the pathogenesis and treatment mode that distinguish PUC from adults and promote precise treatment for PUC.