title: Appendix is a priming site in the development of ulcerative colitis.
abstract: OBJECTIVE
  The role of the appendix has been highlighted in the pathogenesis of ulcerative colitis (UC). The aims of this study were to elucidate the immuno-imbalances in the appendix of UC patients, and to clarify the role of the appendix in the development of UC.
  
  
  METHODS
  Colonoscopic biopsy specimens of the appendix, transverse colon, and rectum were obtained from 86 patients with UC: active pancolitis (A-Pan; n = 15), active left-sided colitis (A-Lt; n = 25), A-Lt with appendiceal involvement (A-Lt/Ap; n = 10), inactive pancolitis (I-Pan; n = 14), and inactive left-sided colitis (I-Lt; n = 22), and from controls. In the isolated mucosal T cells, the CD4/CD8 ratio and proportion of activated CD4+ T cells were investigated, and compared with controls.
  
  
  RESULTS
  In the appendix, the CD4/CD8 ratio significantly increased in A-Lt and A-Lt/Ap. The ratio in the appendix also tended to increase in A-Pan. In the rectum, the ratio significantly increased in all UC groups. In the appendix, the proportion of CD4+CD69+ (early activation antigen) T cells significantly increased in all UC groups. In the rectum, the proportion of CD4+CD69+ T cells significantly increased only in A-Pan. The proportion of CD4+HLA-DR+ (mature activation antigen) T cells significantly increased only in the rectum of A-Pan, but not in the other areas of any groups.
  
  
  CONCLUSIONS
  The increased CD4/CD8 ratio and predominant infiltration of CD4+CD69+ T cells in the appendix suggest that the appendix is a priming site in the development of UC.
authors.affiliation: Third Department of Internal Medicine, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8506, Japan. matsumit@takii.kmu.ac.jp
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Matsushita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takakuwa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsubayashi
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Nishio
authors.forename: Susumu
authors.initials: S
authors.lastname: Ikehara
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Okazaki
mesh_terms: D000328:Adult; D001065:Appendix / Q000473:pathology*; D001706:Biopsy; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003093:Colitis, Ulcerative / Q000209:etiology / Q000473:pathology*; D003113:Colonoscopy; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008531:Megacolon / Q000473:pathology*; D008875:Middle Aged; D012016:Reference Values