The main objective of our study was to assess the frequency of FOXP3+CD4+CD25+ T regulatory cells in peripheral blood and of FOXP3+ cells in mucosal biopsy specimens from IBD patients before and after different anti-TNFα therapies, correlating the results with clinical response, C-reactive protein (CRP) levels, and age and duration of disease. This evidence concerns the gene FOXP3 and irritable bowel syndrome.