In immunocompetent Smarca4ΔILC3 mice lacking Brg1 in both ILC3s and T cells, no discernable symptoms of colitis occurred before 8 weeks, although proportions of activated T cells was increased probably due to impaired function of Tregs.39 It is likely that the pathogenicity of ILC3s was inhibited by the adaptive immune system in immunocompetent Smarca4ΔILC3 mice.52 Firstly, numbers of ILCs were less in immunocompetent mice compared to Rag1−/− mice.59 Therefore, even though GM-CSF production from Smarca4ΔILC3 mice was higher than controls, it may not mount a pathogenic level to cause colitis. Here, RAG1 is linked to colitis.