IL23A and inflammatory bowel disease 30: Our data support context-specific roles of IL-23 in driving the differentiation of pathogenic Th17/Th1 cells in the presence of IL-129 that are enriched in inflamed intestinal tissue from patients with IBD30 31 while supporting the development of non-pathogenic Th17 cells under homeostatic conditions such as those found in mucosa-associated lymphoid tissue (MALT) - in healthy individuals.