CCL20, a member of the CC chemokine family, exerts its effects via binding to the chemokine receptor CCR6.[32] During active IBD, both the chemokine ligand CCL20 and its receptor CCR6 are upregulated in colonic biopsy samples.[33] In CD, abnormally elevated mucosal CCL20 drives Th17 cell infiltration, exacerbating mucosal damage.[34] Here, our results further confirm the causal relationship between CCL19 and IBD. This evidence concerns the gene CCL19 and Cowden disease.