CD4 and inflammatory bowel disease: However, no validated, inexpensive, or sensitive models for the prediction of risk are available for complicated CD.[3] Increasing evidence shows that T cells, including CD4+ and CD8+ T cells and especially regulatory T cells (Tregs, mainly consisting of CD4+CD25+[4] and CD8+CD28– T cells[5]), play a primary role in the immunologic pathogenesis of IBD, and thus we believe that T cell subsets will be ideal biomarkers in prognosis prediction for complicated CD.