Increased expression of interleukin 17 in inflammatory bowel disease.
OBJECTIVE
Interleukin (IL) 17 is a cytokine which exerts strong proinflammatory activities. In this study we evaluated changes in IL-17 expression in the inflamed mucosa and in the serum of patients with inflammatory bowel disease (IBD).


METHODS
Tissue samples were obtained endoscopically or surgically from patients with ulcerative colitis (UC) (n=20), Crohn's disease (CD) (n=20), infectious colitis (n=5), ischaemic colitis (n=8), and normal colorectal tissues (n=15). IL-17 expression was evaluated by a standard immunohistochemical procedure. Serum IL-17 levels were determined by ELISA. IL-17 mRNA expression was analysed by reverse transcriptase-polymerase chain reaction.


RESULTS
IL-17 expression was not detected in samples from normal colonic mucosa, infectious colitis, or ischaemic colitis. In the inflamed mucosa of active UC and CD patients, IL-17 expression was clearly detectable in CD3(+) T cells or CD68(+) monocytes/macrophages. The average number of IL-17(+) cells was significantly increased in active UC and CD patients compared with inactive patients. IL-17 mRNA expression was not detected in normal mucosa but was detectable in the mucosa from active UC and CD patients. IL-17 was not detected in the sera from normal individuals, infectious colitis, or ischaemic colitis patients but IL-17 levels were significantly elevated in IBD patients.


CONCLUSIONS
IL-17 expression in the mucosa and serum was increased in IBD patients. It is likely that IL-17 expression in IBD may be associated with altered immune and inflammatory responses in the intestinal mucosa.
Fujino
S
S
Department of Internal Medicine, Shiga University of Medical Science, Seta-Tukinowa, Otsu 520-2192, Japan.
Andoh
A
A
Bamba
S
S
Ogawa
A
A
Hata
K
K
Araki
Y
Y
Bamba
T
T
Fujiyama
Y
Y
D000208:Acute Disease; D016022:Case-Control Studies; D003092:Colitis / Q000276:immunology / Q000382:microbiology; D017091:Colitis, Ischemic / Q000276:immunology; D003093:Colitis, Ulcerative / Q000276:immunology; D003424:Crohn Disease / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D020381:Interleukin-17 / Q000032:analysis* / Q000097:blood / Q000235:genetics; D007413:Intestinal Mucosa / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology
D020381:Interleukin-17; D012333:RNA, Messenger