IL1B and inflammatory bowel disease: When the immuno-cellular factors for the improvement of IBD symptoms were investigated, the number of Foxp3+ T cells in the CD4+CD45.2+ population was higher (Fig. 4e), and the level of TNFα or IL-1β in the serum was substantially lower in CD4+Foxp3+ or CD4+Lrig1+ T cell recipients than those in CD4+Lrig1− T cell recipients (Fig. 4f).