Delineation of Inflammatory Bowel Disease by Molecular Biometrics: Verification versus Validation

Dysregulated immune responses to the gut microbiota are believed to be the driving force in the development of inflammatory bowel diseases. Even with combined modern and newer diagnostic technologies, it is difficult to accurately differentiate colonic inflammatory bowel disease, namely ulcerative colitis and Crohn’s colitis. Regardless of current advanced clinical and pathological criteria available to identify factors possible to help delineate the two entities, a subgroup of Crohn’s colitis cases are still diagnosed as ulcerative colitis. Current classification criteria as well as diagnostic modalities such as serologic, genetic and inflammatory markers fail to differentiate ulcerative colitis from Crohn’s colitis among patients with indeterminate colitis. The definitive diseases share demographic and clinical features, yet differ in tissue inflammation and damage suggesting distinct trigger and mechanisms. Since treatments differ, a biological dysregulation underlying the two forms of inflammatory bowel disease need to be elucidated in order to develop appropriate treatment strategies that achieve long-term remission and minimize risk of relapse. A molecular diagnostic tool would greatly benefit indeterminate colitis patients. Herewith, we summarize advances and explain the attempts to resolve indeterminate colitis into Crohn’s colitis and ulcerative colitis; and ascertain whether Crohn’s colitis patients mistakenly operated for definitive ulcerative colitis can molecularly be identifiable prior to surgery.