We include and follow up on 102 adults with active ulcerative colitis. Visits are week 0 (inclusion), 6, 12 and 26 (end of study). We obtain plasma and fecal samples at each visit. Whereas we obtain colonic tissue samples only at inclusion and end of study.~Registered data are:~Demographics realate to UC and general wellbeing.~Clinical parametres used for UC evaluation are PRO2, SCCAI, CRP, fecal calprotectin, Mayo endoscopic subscore and Nancy index.~The contact activation system is characterised by FXII, prekallikrein, kallikrein generation, HK, cHK (specific to plasma kallikrein), cHK (specific to tissue kallikrein), C1 inhibitor and Kallistatin.~Polymerized alpha-1-antitrypsin is characterised by the degree of polymerization and the capacity to activate the contact activation system.
The study aims to describe alterations in the contact activation system during active and inactive ulcerative colitis.~Contact activation system measures are compared in a cross sectional (healthy controls vs. active disease) and longitudinal (active diasese vs. inactive disease) fashion.