Inflammatory bowel disease (IBD) patients represent a heterogeneous group of patients that may need novel classification beyond just Crohns’ disease (CD) and ulcerative colitis (UC). Notably, based on patient specifics such as genetics, disease location, immune responses and drug responsiveness, it seems likely that early-onset IBDs represents a specific disease entity.1 Consequently, various disease-associated effector T cells have been identified, probably generated under the control of cytokines that are produced by antigen-presenting cells. In their recent publication, Kugathsan et al demonstrated that the level of IL12β2 (interleukin 12 receptor) expression by mucosal T cells may be a major determinant during the initial manifestations of CD for the development of the typically associated mucosal Th1 cytokine profile.2 In this case, the presence of a specific T cell receptor correlated …