assessment of cytokines in inflammatory bowel disease: Comparison between local mRNA expression and clinical findings *
Background : It has been described that various cytokines mediate mucosal inflammation in ulcerative colitis (UC) and Crohn's disease (CD), The aim of this study was to characterize mRNA expression of various cytokines in the intestinal mucosa of CD and UC, and to correlate it with clinical features of the diseases. Subjects and methods : 1) Total RNA was extracted from rectal biopsy specimens obtained from 79 patients with UC, 18 patients with CD, 13 inflammatory controls and 16 noninflammatory controls. mRNA expression of IL-2, IFN- γ , IL-4, IL-10, IL-13 and IL-15 was determined by means of reverse transcription (RT) - PCR. Positive rate of each cytokine was compared among the four groups of subjects. In UC patients, positive rate was compared among subgroups divided by disease activities and clinical course. 2) Cytokine expression in the ileal biopsy specimens was determined in 36 patients with CD, 14 inflammatory controls and 16 noninflammatory controls. The positive rate was compared among the three groups of subjects. Results : 1) Positive rates of IL-4, IL-10 and IL-13 were higher in the specimens from UC patients than in those from noninflammatory controls. IL-4 was more frequently positive in UC than in inflammatory controls. In addition, positive rate of IL-13 was higher in the specimens from UC patients than in those from CD patients. While IL-4 and IL-13 were more frequently positive in active UC, positive rate of any cytokines was not different among the groups classified by the subsequent clinical course. 2) In ileal biopsy specimens, IL-10 was more frequently positive in CD than in the noninflammatory controls, but the value did not differ from that in the inflammatory controls. Conclusions : There seems to be a difference in the mRNA expression of cytokines in the intestinal mucosa between CD and UC. IL-4 and IL-13 are pivotal in active UC, thereby suggesting that these cytokines play an important role in the pathogenesis of UC. Local expression of IL-10 is not specific to IBD, but it is rather overexpressed in nonspecifically inflamed mucosa. (Accepted on September 16, 1999) Kawasaki Igakkaishi 25(4 ) : 257―267, 1999
