Anti-SEB positive stained cells were located in the colonic mucosa. Colonic biopsies were got from the patients with UC-only (A) and the patients with UC-CRS (B and C). Cryosections were stained with anti-SEB antibody or IgG isotype control immunoglobulin (B). Sections were visualized by the immunoperoxidase method and counterstained with hematoxylin. SEB specific IgE-bearing cells were stained in brown (C). ×200.