*Diagnostic role of upper endoscopy in differentiating ulcerative colitis from Crohn*s disease in adults*

The distinction between ulcerative colitis (UC) and Crohn*s disease (CD) is
difficult to make in approximately 15% of patients with Inflammatory Bowel
Disease (IBD). The differentiation between different IBD phenotypes has major
implications, such as the choice of medical treatment, timing en type of
surgery (ileal pouch anal anastomosis IPAA), prognosis, disease course and
surveillance protocols. The macroscopic, histologic and immunologic findings at
upper endoscopy (UE), at the time of primary diagnosis, could play a role in
the early differentiation between different IBD phenotypes, especially in
patients with IBD *unclassified*. Until now, no studies had addressed this
hypothesis properly, in adult patients.
Furthermore, very little is known about the mucosal proinflammatory cytokine
expression in gastroduodenal lesions of patients with Crohn*s disease. No
studies have yet compared the mucosal cytokine profile of the gastric, duodenal
and intestinal lesions in patients with Crohn*s disease and ulcerative colitis,
in relation to the circulating memory T lymphocytes.

Our hypothesis is that findings at upper endoscopy (endoscopic, histologic and
immunologic) at the time of the primary diagnosis of IBD and before starting
medication, could be useful in differentiating between different IBD
phenotypes, and extend our knowledge of the pathogenesis of this heterogeneous
disease.
Regarding the mucosal T cell populations and their cytokine profile, our
hypothesis is that they may be heterogeneous according to the IBD phenotype and
location within the gastrointestinal tract, and are related to the type of
circulating memory T lymphocytes.

1. Determine the presence of lesions in the upper gastrointestinal tract in
patients with a primary diagnosis of CD and UC, using endoscopy and histology,
before starting medication.
2. Asses the prevalence of histological lesions such as focal enhanced
gastritis in different IBD phenotypes, in the absence of Helicobacter pylori.
3. Asses the T-cell subpopulation and their profile of proinflammatory
cytokines in the peripheral blood and both gastroduodenal lesions and
intestinal lesions, in different IBD phenotypes.
4. Asses the value of findings at upper endoscopy (macroscopic, histologic and
immunologic) in differentiating between different IBD phenotypes.

Longitudinal, prospective, cohort study.
All patients will undergo an ileocolonoscopy and upper endoscopy as part of the
standard clinical care. If during these procedures, macroscopic lesions will be
seen suggesting the diagnosis IBD, a double number of biopsies for histological
and immunological examination will be taken. One extra blood sample (10 ml)
will de taken during teh standard laboratory test.

Upper endoscopy and ileocolonoscopy are standard examinations in patients with
chronic (+/- bloody) diarrhoea. The diagnostic gastroenterological endoscopies
are generally safe procedures. The only additional intervention, in patients
who are strongly suspected of IBD during endoscopy, will be a higher number of
biopsies taken for both histological and immunological examination, which has a
negligible risk of bleeding. One extra blood sample (10 ml) will de taken
during the standard laboratory test.