TNFSF15 and Crohn ileitis: In particular, early studies in murine models of ileitis and colitis have shown that TL1A was mainly expressed by CD11chigh/MHC-II+ mononuclear phagocytes of the lamina propria and the MLNs and CD11clow/MHC-II− mononuclear phagocytes of the lamina propria that probably represent dendritic cells and macrophage subsets (35, 36).