Interleukin-27 Is a Potential Rescue Therapy for Acute Severe Colitis Through Interleukin-10–Dependent, T-Cell–Independent Attenuation of Colonic Mucosal Innate Immune Responses

Background; IBD patients with acute severe colitis face systemic anti-TNF biologic rescue therapy or colectomy, if treatment with intravenous steroids fail. Interleukin (IL)-27 is a cytokine with an immunosuppressive role in adaptive immune responses. However, the IL-27 receptor complex is also expressed on innate immune cells, and there is evidence that IL-27 can impact the function of innate cell subsets, although this particular functionality in vivo is not understood. Our aim was to define the efficacy of IL-27 in acute severe colitis and characterize novel IL-27 driven mechanisms of immunosuppression in the colonic mucosa.


Methods; We assessed oral delivery of Lactococcus lactis expressing an IL-27 hyperkine on the innate immune response in vivo in a genetically intact, non-infective acute murine colitis model induced by intra-rectal instillation of 2,4,6-Trinitrobenzenesulfonic acid in SJL/J mice.


Results; IL-27 attenuates acute severe colitis through reduction of colonic mucosal neutrophil infiltrate associated with a decreased CXC chemokine gradient. This suppression was T cell-independent and IL- 10-dependent, initially featuring enhanced mucosal IL-10. IL-27 was associated with a reduction in colonic pro-inflammatory cytokines and induced a multifocal strong positive nuclear expression of phosphorylated STAT-1 in mucosal epithelial cells.


Conclusion; We have defined novel mechanisms of IL-27 immunosuppression towards colonic innate immune responses in vivo. Mucosal delivery of IL-27 has translational potential as a novel therapeutic for IBD and is a future mucosal directed rescue therapy in acute severe inflammatory bowel disease.