In contrast to Ctla4 sufficient Rag2−/− mice, where faecal transplantation had no appreciable impact, in Rag2−/−x Ctla4−/− double knockout mice transplantation induced features of colitis, including increased colon mass, splenomegaly, increased infiltration of Gr-1hi neutrophils and expansion of IFNγ producing ILC1s and NKp46+ ILC3s (Fig. 3e–g and Supplementary Figs. 10a, 11a–e). The gene discussed is CTLA4; the disease is colitis.