Advance on mathematical models in inflammatory bowel disease

A mathematical model (MM) is a tool that imitates reality by using the language of function. It is often represented as a scoring system in medicine. The efficiency of MM is directly reflected in its specificity and sensitivity. In the field of inflammatory bowel disease (IBD), MM, such as the Best CDAI, HBI, CDISS, SES-CD, Lewis score, Rutgeerts score, MaRIA, and Clermont score, can assist in the diagnosis, evaluation and prognosis. However, these models are dependent on clinical symptoms, endoscopy and imaging findings, which are also limited to subjective experience of clinicians. There are also defects such as difficulty in obtaining indicators or high expense. A few peripheral blood markers that are easy to obtain, especially immunologic markers, aren't included in the variables for modeling, which affects the efficiency of MM. It was found in the previous series of studies on animals and humans that peripheral blood CD8⁺CD28⁺/CD8⁺CD28^- T cell ratio (equilibrium) showed a powerful efficiency in predicting the stage for experimental colitis rats. Clinical studies also found that the decrease of this ratio could accurately predict the active stage of IBD, and that this ratio could sensitively predict whether Crohn's disease progresses from non-stricturing and non-penetrating (type B1) to stricturing (B2) or penetrating (B3). Since the immunological mechanisms are vital for the pathogenesis of IBD, we summarize the current major MMs and combine our previous research foundations and thus propose that an immunology-combining MM could be more powerful in diagnosing and predicting outcomes for IBD.