Clinical relevance of serum interleukin-6 in Crohn's disease: single point measurements, therapy monitoring, and prediction of clinical relapse

Am J Gastroenterol. 1999 Aug;94(8):2156-64. doi: 10.1111/j.1572-0241.1999.01288.x.


Objective: To investigate the clinical relevance of interleukin-6 (IL-6) serum levels in patients with Crohn's disease (CD), single point IL-6 measurements in sera from consecutive CD patients and healthy donors (HD), as well as longitudinal measurements during the course of steroid therapy for active CD were performed. Patients with steroid-induced remission were followed until clinical relapse.

Methods: One hundred thirty-six CD patients without steroid or other immunosuppressive treatment within 2 months and surgical procedures within 3 months before study entry were investigated; 63 patients with active CD were enrolled into the follow-up program. Clinical activity was evaluated by the Crohn's disease activity index (CDAI) and serum IL-6 levels measured by enzyme-linked immunosorbent assay.

Results: IL-6 serum levels were significantly elevated in CD patients compared to HD (p < 0.001). In individual patients serum IL-6 levels correlated with corresponding CDAI scores in a subgroup referred to as primarily inflammatory patients presenting without bowel stenosis, previous intestinal resection, or concomitant inflammatory disorders (r = 0.72, p < 0.001). Primarily inflammatory patients displayed higher serum IL-6 levels (median: 6.0 pg/ml; range: 1.3-25) than CD patients with bowel stenosis (median: 2.0; range: 1.3-4.9; p < 0.01) or extensive intestinal resection (median: 1.5; range: 1.3-13.7; p < 0.001). Longitudinally measured serum IL-6 levels reflected the clinical response during steroid therapy and predicted clinical relapse after steroid-induced remission at week 9 of the treatment protocol.

Conclusions: Serum IL-6 is a clinically relevant parameter for CD that correlates with inflammatory activity and implies a prognostic value after steroid-induced remission.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Inflammatory Agents / therapeutic use
  • Crohn Disease / diagnosis*
  • Crohn Disease / drug therapy
  • Crohn Disease / immunology
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Follow-Up Studies
  • Humans
  • Interleukin-6 / blood*
  • Male
  • Middle Aged
  • Prednisolone / therapeutic use
  • Recurrence
  • Treatment Outcome


  • Anti-Inflammatory Agents
  • Interleukin-6
  • Prednisolone