Interleukin 12 is expressed and actively released by Crohn's disease intestinal lamina propria mononuclear cells

Gastroenterology. 1997 Apr;112(4):1169-78. doi: 10.1016/s0016-5085(97)70128-8.


Background & aims: Cell-mediated immunity is a feature of Crohn's disease (CD). The heterodimer interleukin (IL)-12, produced by phagocytes, induces T-cell cytokines, primarily interferon (IFN)-gamma. This study examined whether CD lamina propria mononuclear cells (LPMCs) express and release bioactive IL-12.

Methods: LPMCs were isolated from 13 patients with CD, 9 with ulcerative colitis (UC), and 13 controls. Messenger RNA for p40 and p35 IL-12 subunits was evaluated by reverse-transcription polymerase chain reaction. IL-12 was measured by enzyme-linked immunosorbent assay in LPMC culture supernatants. The INF-gamma-inducing effect of unstimulated LPMC supernatants was evaluated.

Results: Messenger RNA for both IL-12 subunits was detected in LPMCs of 11 of 13 patients with CD, 1 of 9 patients with UC, and 1 of 13 controls (P < 0.001). IL-12 was measured (10.5 +/- 2 pg/mL at 24 hours) in unstimulated CD LPMCs and was enhanced by pokeweed mitogen, lipopolysaccharide, and staphylococcal enterotoxin B. No IL-12 was detectable in 8 of 9 patients with UC and 12 of 13 control-unstimulated LPMCs. IL-12 induced by pokeweed mitogen and staphylococcal enterotoxin B in UC was lower than in CD and did not differ from controls. An IFN-gamma-inducing effect was restricted to unstimulated CD LPMC supernatants and was inhibited by an anti-IL-12 antibody in a dose-dependent fashion.

Conclusions: IL-12 transcripts are expressed in CD intestinal tissues. CD LPMCs are up-regulated in their capability of releasing bioactive IL-12. Expression and release of bioactive IL-12 seem to differentiate CD from UC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Cells / metabolism
  • Cells, Cultured
  • Colitis, Ulcerative / metabolism
  • Colitis, Ulcerative / pathology
  • Crohn Disease / metabolism*
  • Crohn Disease / pathology
  • Humans
  • Interferon-gamma / metabolism
  • Interleukin-12 / genetics
  • Interleukin-12 / metabolism*
  • Intestinal Mucosa / metabolism*
  • Intestines / pathology
  • Monocytes / metabolism*
  • RNA, Messenger / metabolism
  • Reference Values


  • RNA, Messenger
  • Interleukin-12
  • Interferon-gamma