The Contact Activation System and Ulcerative Colitis

Inclusion Criteria: * Fulfill diagnostic criteria of ulcerative colitis * SCCAI score ≥ 5 * Mayo Endoscopic Subscore ≥ 1 * Age ≥ 18 years * Most understand written and oral information in Danish * Informed consent must be given Exclusion Criteria: * Pregnancy * Infection at inclusion * Any existing disease at inclusion: * liver disease or defect in CAS * inflammatory rheumatologic or dermatologic disease * cardiovascular or renal disease * immunodeficiency or hematologic diseases * malignancies * Medication with * Systemic corticosteroids at inclusion * ACE-inhibitor * Acetylsalicylic acid/NSAID * Warfarin, Phenprocoumon, NOAC and heparins