To verify that impaired AREG expression contributes to the development of severe colonic ulceration in Ifnar1−/−Ifnlr1−/− mice following DSS-induced colitis, we conducted a rescue experiment and administered exogenous AREG to Ifnar1−/−Ifnlr1−/− mice on days 5, 7, 9, and 11 of the DSS treatment protocol. This evidence concerns the gene AREG and colitis.