Development of a New Algorithm to Determine the Activity of Disease: Deep Endoscopic Remission Assessed by a Surrogate Biomarker in Patients With IBD.

Deep remission: The treatment goal in patiens with IBD is to achieve deep remission before drug withdrawal to avoid relapse. In order to evaluate the healing of mucosa, it is currently necessary to carry out an endoscopy, despite the additional information provided by FC and blood samples. The endoscopic procedure is uncomfortable for the patient, time consuming and expensive. We therefore seek, on the basis of existing knowledge and using a correlation between FC, blood tests and clinical remission with endoscopic findings, to establish some non-invasive biomarkers that might express deep remission. In the long run, threshold levels will be used as indicators for performing an endoscopy and, hopefully, reduce the need for it to be performed. We will compare the results from children and adults because it is likely there exist differences in their respective FC levels.

Histopathologic remission: Biopsies of the intestinal tissue can be evaluated histopathologically and indicate the level of microscopic inflammation and can assess the acute and chronic inflammatory signs at the cellular level, e.g. altered glandular structure, crypt abscess and ulcerations. By using the Karl Geboes grading system, microscopic histopathological deep remission can be assessed. We will explore the endoscopic 'gold standard' by comparing endoscopic remission with histopathological remission.

Immunological remission: In general, tissue factors are linked to various immunological pathways belonging to the innate, adaptive and regulatory immune response, comprising a pro-inflammatory and an anti-inflammatory response. This includes molecules such as cytokines, chemokines, adhesion molecules and their corresponding cellular and soluble receptors. Tumor-necrosis-factor (TNF)-alpha and interleukin 17A is two of several molecules in the pro-inflammatory process that is strongly associated with the grade of inflammation in IBD (Florholmen and Fries 2011). Olsen et al. 2009 have reported that a normalization of mucosal TNF-alpha in most ulcerative colitis patients will represent an endoscopically healed mucosa.

In addition to clinical indexes, endoscopic and histological criteria, we also introduce a molecular based Immunological Remission. A working hypothesis is that immunological remission is a state of normalization of the pro-inflammatory and anti-inflammatory processes in mucosa. The concept of immunological remission and the potential clinical impact are still in the early phases of evaluation, and to obtain a practical application a non-invasive test, such as one based on a stool sample, must be developed. In the current project, immunological remission will be a part of this study, as endoscopic and histopathology remission, with correlation to FC, blood tests and clinical remission.