Among these IBD‐related isoforms, full‐length CD28 was demonstrated to show a higher binding affinity with CD80/CD86, while both CD28i and CD28Δex2 were confirmed as loss‐of‐function spliced products that might decrease the disease risk through bringing out anergy of effector T cells, inducing tolerance, and inactivation to intestinal antigens and allergens (Figure 5H).118. Here, CD28 is linked to inflammatory bowel disease.