FoxP3+ Tregs spread and collect on the inflamed mucosa of the inflammatory bowel disease (IBD) patients.5, 6 T helper cells produce IL‐17 (Th17 cells) for mucosal homoeostasis and are implicated in the pathogenesis of CD.7, 8 Th17 cells would protect the host from infection at mucosal surfaces, whereas Tregs control immune responses and inflammation caused by the microflora.9, 10. This evidence concerns the gene IL17A and inflammatory bowel disease.