To dissect the involvement of ILC in this process, chronic DSS colitis was induced in wild type (WT), in recombination activating gene (RAG−/−) deficient mice (which lack adaptive immunity but have a normal ILC population), in anti‐CD90.2 injected RAG−/− mice and in RAG−/− common γ chain−/− (RAG−/−γc−/−) mice which both also lack the ILC population. Here, CCL27 is linked to colitis.