BTNL3 and ulcerative colitis: In a previous study from the Hayday group, it was already shown that the human colon harbors intraepithelial Vγ4-expressing γδ T cells which can specifically interact with BTNL3/BTNL8 heterodimers expressed on the colonic epithelial cells (Fig. 1b).5 However, it remained unresolved whether the reciprocal liaison of intraepithelial Vγ4γδ T cells with epithelial BTNL3/BTNL8 ligands has any implications for chronic inflammatory bowel diseases (IBD) like Crohn’s disease (CD) and ulcerative colitis (UC).