IL-23–responsive innate lymphoid cells are increased in inflammatory bowel disease

A Geremia, CV Arancibia-Cárcamo… - Journal of Experimental …, 2011 - rupress.org
A Geremia, CV Arancibia-Cárcamo, MPP Fleming, N Rust, B Singh, NJ Mortensen
Journal of Experimental Medicine, 2011rupress.org
Results of experimental and genetic studies have highlighted the role of the IL-23/IL-17 axis
in the pathogenesis of inflammatory bowel disease (IBD). IL-23–driven inflammation has
been primarily linked to Th17 cells; however, we have recently identified a novel population
of innate lymphoid cells (ILCs) in mice that produces IL-17, IL-22, and IFN-γ in response to IL-
23 and mediates innate colitis. The relevance of ILC populations in human health and
disease is currently poorly understood. In this study, we have analyzed the role of IL-23 …
Results of experimental and genetic studies have highlighted the role of the IL-23/IL-17 axis in the pathogenesis of inflammatory bowel disease (IBD). IL-23–driven inflammation has been primarily linked to Th17 cells; however, we have recently identified a novel population of innate lymphoid cells (ILCs) in mice that produces IL-17, IL-22, and IFN-γ in response to IL-23 and mediates innate colitis. The relevance of ILC populations in human health and disease is currently poorly understood. In this study, we have analyzed the role of IL-23–responsive ILCs in the human intestine in control and IBD patients. Our results show increased expression of the Th17-associated cytokine genes IL17A and IL17F among intestinal CD3 cells in IBD. IL17A and IL17F expression is restricted to CD56 ILCs, whereas IL-23 induces IL22 and IL26 in the CD56+ ILC compartment. Furthermore, we observed a significant and selective increase in CD127+CD56 ILCs in the inflamed intestine in Crohn’s disease (CD) patients but not in ulcerative colitis patients. These results indicate that IL-23–responsive ILCs are present in the human intestine and that intestinal inflammation in CD is associated with the selective accumulation of a phenotypically distinct ILC population characterized by inflammatory cytokine expression. ILCs may contribute to intestinal inflammation through cytokine production, lymphocyte recruitment, and organization of the inflammatory tissue and may represent a novel tissue-specific target for subtypes of IBD.
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