Therefore, it was hypothesized that targeting Th17 cells (or their effector cytokines) may protect against severe CDI in patients with inflammatory bowel disease.148 In line with that, IL-23a (p19) knock-out mice were fully protected from C. difficile challenge and had lower morbidity, whereas their wild-type counterparts had significantly lower survival (16.7% on day 2 of infection).143 Similar results were obtained by neutralizing IL-23 using a monoclonal antibody. This evidence concerns the gene IL23A and inflammatory bowel disease.