Interleukin-6 and soluble interleukin-6 receptor in the colonic mucosa of inflammatory bowel disease

J Gastroenterol Hepatol. 1999 Oct;14(10):987-96. doi: 10.1046/j.1440-1746.1999.01989.x.


Background: Interleukin-6 (IL-6) has multiple immunological effects on a wide variety of cells and tissues. The expression of IL-6 and IL-6 receptor (IL-6R) may be important to the pathogenesis of inflammatory bowel disease (IBD).

Methods: In the present study, we examined whether mucosal IL-6 and soluble IL-6R were associated with the pathophysiology of IBD using the colonic mucosal specimens obtained from patients with IBD. Enzyme-linked immunosorbent assay was used to measure the levels of IL-6 and sIL-6R in organ cultures of mucosal tissues and in cell cultures of fractionated mucosal cells as well as in the serum. Expression of IL-6 and IL-6R was analysed by reverse transcription-polymerase chain reaction analysis using freshly isolated lamina propria mononuclear cells (LPMC).

Results: The levels of IL-6 and sIL-6R in organ cultures were substantially elevated in patients with IBD, especially in those with histologically active inflammation. In contrast, considerably higher levels of sIL-6R were detected in patients with other types of colonic inflammation who were included as inflammatory controls, but elevation of IL-6 was less prominent in such patients. The positivity for expression of IL-6 and IL-6R mRNA in LPMC was in parallel with the results obtained in organ cultures. In cell cultures, mucosal macrophages were the main cell type producing both IL-6 and sIL-6R on a per cell basis and other cell fractions including colonic epithelial cells and lymphocytes produced substantially lower amounts of these molecules. The levels of IL-6 and sIL-6R in organ cultures, but not those in the serum, showed a significantly positive correlation with the degree of clinical disease activity in patients with IBD.

Conclusions: Enhanced IL-6/sIL-6R-mediated immune and inflammatory responses may be implicated, at least partly, in the continuation of intestinal inflammation in patients with IBD.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, CD / metabolism
  • Cells, Cultured
  • Child
  • Colon / metabolism*
  • Culture Techniques
  • Female
  • Humans
  • Inflammatory Bowel Diseases / blood
  • Inflammatory Bowel Diseases / metabolism*
  • Interleukin-6 / biosynthesis*
  • Interleukin-6 / blood
  • Interleukin-6 / genetics
  • Intestinal Mucosa / metabolism*
  • Leukocytes, Mononuclear / metabolism
  • Macrophages / metabolism
  • Male
  • Middle Aged
  • RNA, Messenger / biosynthesis
  • Receptors, Interleukin-6 / biosynthesis*
  • Receptors, Interleukin-6 / blood
  • Receptors, Interleukin-6 / genetics


  • Antigens, CD
  • Interleukin-6
  • RNA, Messenger
  • Receptors, Interleukin-6