title: Reduced Numbers and Proapoptotic Features of Mucosal-associated Invariant T Cells as a Characteristic Finding in Patients with Inflammatory Bowel Disease.
abstract: BACKGROUND
  Mucosal-associated invariant T (MAIT) cells are innate-like T cells involved in the homeostasis of mucosal immunity; however, their role in inflammatory bowel disease (IBD) is unclear.
  
  
  METHODS
  Flow cytometry was used to enumerate peripheral blood MAIT cells in 88 patients with ulcerative colitis (UC), 68 with Crohn's disease (CD), and in 57 healthy controls. Immunohistochemistry identified MAIT cells in intestinal tissue samples from patients with UC (n = 5) and CD (n = 10), and in control colon (n = 5) and small intestine (n = 9) samples. In addition, expression of activated caspases by MAIT cells in the peripheral blood of 14 patients with UC and 15 patients with CD, and 16 healthy controls was examined.
  
  
  RESULTS
  Peripheral blood analysis revealed that patients with IBD had significantly fewer MAIT cells than healthy controls (P < 0.0001). The number of MAIT cells in the inflamed intestinal mucosae of patients with UC and CD was also lower than that in control mucosae (P = 0.0079 and 0.041, respectively). The number of activated caspase-expressing MAIT cells in the peripheral blood of patients with UC and CD was higher than that in healthy controls (P = 0.0061 and 0.0075, respectively), suggesting that the reduced MAIT cell numbers in IBD are associated with an increased level of apoptosis among these cells.
  
  
  CONCLUSIONS
  The number of MAIT cells in the peripheral blood and inflamed mucosae of patients with UC and CD was lower than that in non-IBD controls. Also, MAIT cells from patients with IBD exhibited proapoptotic features. These data suggest the pathological involvement and the potential for therapeutic manipulation of these cells in patients with IBD.
authors.affiliation: *Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan; †Department of Gastroenterology and Hepatology, Graduate School of Medicine, Kyoto University, Kyoto, Japan; ‡Department of Anatomical, Forensic Medicine, and Pathological Studies, Graduate School of Medicine, Kyoto University, Kyoto, Japan; §Department of Internal Medicine, Division of General Medicine, Hyogo College of Medicine, Hyogo, Japan; ‖Department of Pediatrics, University of Toyama, Toyama, Japan; ¶Department of Pediatrics, Shiga University of Medical Science, Shiga, Japan; **Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan; ††Department of Clinical Laboratory, Kyoto University Hospital, Kyoto, Japan; ‡‡Department of Surgery, Hyogo College of Medicine, Hyogo, Japan; §§Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan; and ‖‖Division of Gastroenterology, Department of Internal Medicine, Keio University School of Medicine, Kyoto, Japan.
authors.forename: Eitaro
authors.initials: E
authors.lastname: Hiejima
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kawai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakase
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Tsuruyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Morimoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yasumi
authors.forename: Takashi
authors.initials: T
authors.lastname: Taga
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kanegane
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hori
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Ohmori
authors.forename: Takeshi
authors.initials: T
authors.lastname: Higuchi
authors.forename: Minoru
authors.initials: M
authors.lastname: Matsuura
authors.forename: Takuya
authors.initials: T
authors.lastname: Yoshino
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ikeuchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawada
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Sakai
authors.forename: Mina T
authors.initials: MT
authors.lastname: Kitazume
authors.forename: Tadakazu
authors.initials: T
authors.lastname: Hisamatsu
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Chiba
authors.forename: Ryuta
authors.initials: R
authors.lastname: Nishikomori
authors.forename: Toshio
authors.initials: T
authors.lastname: Heike
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007113:Immunity, Innate; D007150:Immunohistochemistry; D015212:Inflammatory Bowel Diseases / Q000276:immunology* / Q000473:pathology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
chemical_list: D016207:Cytokines