2.2. Intestinal biopsies collection

Intestinal biopsies were collected within the context of the 1000IBD project and Dutch parelsnoer IBD Biobank at time of colonoscopy procedures, which were part of standard clinical care. Intestinal biopsies were snap-frozen in liquid nitrogen shortly after the colonoscopy procedure. Biopsies were stored at −80°C until further processing. In total, 760 intestinal biopsies from 371 patients with IBD were analyzed in this study. During the endoscopic procedure, the inflammatory status of the biopsy was macroscopically categorized by assessing the mucosal morphology. Macroscopic inflammation was characterized by redness and edema, with or without ulceration of the intestinal mucosa. Additionally, histopathological evaluation later confirmed the macroscopic inflammation status.