The influence of cigarette smoking on cytokine levels in patients with inflammatory
bowel disease Anecdotal reports suggest that smoking may be beneficial for patients
with inflammatory bowel disease (IBD) as nicotine may act through inflammatory
mediators within the colonic mucosa. Furthermore, there is increasing evidence
that cytokines play a pathologic role in IBD. Our aim was to determine the effects
of cigarette smoking on cytokine levels in the colonic mucosa of patients with
and without IBD. Mucosal biopsies were obtained from 10 patients with Crohn's
disease (CD), 10 with ulcerative colitis (UC), and 10 healthy controls. Five
of 10 patients in each of the three groups were smokers and five were
nonsmokers. Concentrations of interleukin (IL)-1beta, IL-2, IL-6, and IL-8
were determined using enzyme-linked immunosorbent assay (ELISA). Cytokine
levels of smokers were compared with nonsmokers in each group and with
controls. Results were analyzed using the Mann-Whitney test; significance
was set at p<0.05. The concentration of IL-8 was significantly higher in
healthy controls who smoke compared with nonsmokers and significantly reduced
in smokers with CD compared with nonsmokers with CD. Moreover, concentrations
of IL-1beta and IL-8 were significantly reduced in smokers with UC compared
with nonsmokers with UC. Smokers had significantly elevated levels of IL-8
in the colonic mucosa. Smokers with IBD had a significant reduction in
cytokine levels; specifically, IL-1beta and IL-8 for patients with UC and
IL-8 for patients with CD. Further studies are warranted to determine if
this reduction in cytokine levels is histologically and clinically significant.
