CTLA4 and inflammatory bowel disease: Polarized Th17 could be responsible for Belatacept-resistant rejection, since an elevated level of Th17 memory cells has been associated with acute rejection with belatacept (85), and as mentioned above, in IBD, which is a Th17-mediated disease, CTLA4-Ig treatment has exhibited minimal efficacy and even, in a few cases, disease exacerbation (121).