ENHANCED INTESTINAL SYNTHESIS OF INTERLEUKIN-6 IS RELATED TO THE DISEASE SEVERITY AND ACTIVITY IN ULCERATIVE-COLITIS

The concentration of interleukin-6 (IL-6) was measured in the perfusion fluid from investigated rectal and sigmoid segments in patients with ulcerative colitis (UC). The colorectal release of this substance from segments with active inflammation was greatly increased compared with that found in healthy controls and correlated to the mucosal damage defined by plasma protein leakage and endoscopic findings. The perfusate/serum ratio of IL-6 was significantly higher than the corresponding ratio of albumin, indicating that the increased amount of IL-6 detected in the perfusion fluid was synthesized in the inflamed colorectal mucosa. A strong correlation between the concentrations of IL-6 and of tumor necrosis factor-alpha in perfusion fluid suggests that macrophages/monocytes are cells of importance in the stimulated local synthesis of IL-6. The calculated total colorectal release of IL-6 was significantly correlated to the serum concentrations of C-reactive protein and alpha 1-antitrypsin, demonstrating that the acute phase response in patients with UC reflects the amount of locally produced IL-6.