Supplementary Material for: Narrow Band Imaging with Magnifying Endoscopy for Peyer's Patches in Patients with Inflammatory Bowel Disease

<b><i>Background/Aims:</i></b> Peyer's patches (PPs) play a major role in mucosal immunity, but little is known about their alterations in patients with inflammatory bowel disease (IBD). We aimed to evaluate endoscopic changes of PPs in IBD patients using narrow band imaging with magnifying endoscopy (NBI-ME). <b><i>Methods:</i></b> Images of PPs using NBI-ME by ileocolonoscopy were consecutively collected. Existence of branch-like structures and the vessel occupancy in the dome lesions of PPs were analyzed. Appearance of the surrounding villi of the domes in PPs was evaluated using a ‘villi index' consisting of irregular formation, hyperemia, and altered vascular network pattern. Vascularity of PPs was immunohistologically analyzed by anti-CD34 antibody. <b><i>Results:</i></b> 17 patients with Crohn's disease (CD), 43 with ulcerative colitis (UC), and 23 healthy control subjects (HC) were analyzed. Both CD and UC patients had a high prevalence of having branch-like structures and significantly higher vascularity in the dome lesions than HC. The villi indices and vascular widths in the villi were significantly larger in CD and UC patients than in HC. <b><i>Conclusions:</i></b> Precise examination with NBI-ME characterized alteration of vascular structure in the dome and surrounding villi lesions of PPs not only in CD but also in UC patients.