These data are in part supported by results derived from the infant mouse infection model, given that in naive as well as in C. jejuni infected infant IL-22−/− mice, colonic IL-23p19 and IL-18 mRNA were down-regulated, which also held true for IL-18 mRNA expression levels in naive and infected infant IL-23p19−/− as compared to WT control mice [36]. Here, IL23A is linked to infection.