Clinical relevance of serum interleukin-6 in Crohn's disease: single point measurements, therapy monitoring, and prediction of clinical relapse.
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.
Reinisch
W
W
Univ.-Klinik für Innere Medizin IV, Abteilung Gastroenterologie und Hepatologie and Institut für Allgemeine und Experimentelle Pathologie, Neues AKH, Vienna, Austria.
Gasché
C
C
Tillinger
W
W
Wyatt
J
J
Lichtenberger
C
C
Willheim
M
M
Dejaco
C
C
Waldhör
T
T
Bakos
S
S
Vogelsang
H
H
Gangl
A
A
Lochs
H
H
D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D003424:Crohn Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000627:therapeutic use; D012008:Recurrence; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D015850:Interleukin-6; D011239:Prednisolone