Saliva Interleukin-6 in patients with inflammatory bowel disease

Objective. The inflammatory bowel diseases ( IBD), Crohn's disease ( CD) and ulcerative colitis ( UC) are chronic inflammatory conditions that affect the gastrointestinal tract. In regulation of this inflammatory process, Interleukin- 6 ( IL-6) has a major role. Overproduction of IL- 6 by immunocompetent cells contributes to development of the inflammatory condition. Elevated levels of IL- 6 in saliva could be expected, because the saliva- producing cells are part of the digestive system. Material and methods. IL- 6 concentrations in saliva and plasma were studied in patients with CD ( n = 15), UC ( n = 7) and reference persons ( RP) ( n = 19) by use of an ELISA method. Results. A significant difference in saliva IL- 6 concentration between CD patients ( median 16.9 ng/ L; p < 0.05) and RP ( median 6.3 ng/ L) was found. A significant difference in plasma IL- 6 concentration between CD ( median 10.3 ng/ L; p < 0.001) or UC ( median 7.8 ng/ L; p < 0.001) and RP ( median 0.8 ng/ L) was observed. In patients with CD, plasma IL- 6 correlated significantly with C- reactive protein ( CRP) as well as albumin. In patients with UC, saliva IL- 6 and plasma IL- 6 correlated significantly with AI ( activity index) scores as well as albumin. In patients with UC, a significant correlation between the saliva and plasma IL- 6 concentrations was found. Conclusions. IL- 6 was found in saliva in patients with IBD, documenting the general involvement of the gastrointestinal tract extending to the mouth cavity, and measuring IL- 6 may be an additional method for evaluating and monitoring the disease activity.