IL1RN and aortitis: On the other hand, like Il25−/−Il1rn−/− mice transferred with Il25−/−Il1rn−/− BM cells, Il25−/−Il1rn−/− mice transferred with Il1rn−/− BM cells showed reduced development of aortitis compared with Il1rn−/− mice transferred with Il1rn−/− BM cells (Fig. 7a), indicating that IL-25 produced by non-immune cells is crucial for the setting.