Background: Cytokines have validated roles in the immunopathogenesis of inflammatory bowel disease (IBD). This study was to investigate the expressions of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, and IL-10 mRNAs in the colonic mucosa of patients with ulcerative colitis (UC) during active and quiescent UC.
Methods: At colonoscopy, biopsies were taken from inflamed and non-inflamed mucosa of patients with steroid-naive UC (n = 15), non-IBD inflammatory colitis controls (ICC, n = 6), and non-colitis controls (NCC, n = 14). The presence of extensive mononuclear cells and neutrophils infiltrate in the lamina propria, cryptitis, and epithelial damage defined an inflammatory lesion in the mucosa. Quantitative cytokine mRNA expressions in biopsies were measured by real-time polymerase chain reaction (PCR).
Results: Of 15 UC patients, 3 remitted with 5-aminosalicylate and 11 received granulocytapheresis; of these, 10 remitted. At baseline, IL-6, IL-8, TNF-alpha, and IL-10 mRNAs were high in inflamed mucosa compared with NCC (P < 0.01). In active UC, IL-6, IL-8 and IL-10 mRNAs were high compared with non-inflamed mucosa (P = 0.03, P = 0.03, P < 0.05, respectively). Both TNF-alpha mRNA (P = 0.03) and IL-6 mRNA (P = 0.04) were higher in UC compared with ICC. Even in non-inflamed mucosa, IL-8 and TNF-alpha mRNA expressions were high compared with NCC. Both IL-6 and IL-8 mRNAs decreased to normal levels after granulocytapheresis.
Conclusions: During active UC, all 4 cytokine mRNA levels were high; only IL-6 and IL-8 mRNAs decreased to normal levels during remission. IL-8 mRNA was high even at sites of endoscopically quiescent UC during active disease. Steroid naïve patients respond well to granulocytapheresis.