Systemic and local cytokine production in quiescent ulcerative colitis and its relationship to future relapse: A prospective pilot study

Background: The main aim of this prospective study was to examine whether systemic (plasma) and local (mucosal) cytokine production is a predictor of future relapse in patients with quiescent ulcerative colitis (UC). The impact of other clinical and laboratory parameters on relapse was also studied. Methods: Fifty consecutive patients with quiescent UC were included. At enrollment, blood and mucosal (rectal biopsies) samples were collected. All patients were followed up regularly for 1 year after enrollment. Plasma and mucosal cytokine levels were measured by enzyme-linked immunosorbent assay. To identify independent significant predictive factors for relapse, time-dependent analyses using the Kaplan-Meier method and the Cox proportional hazard model were performed. Results: Thirty-four patients remained in remission, and 16 patients relapsed during the 1-year follow-up. Higher interleukin (IL)-8 levels in the rectal mucosa were significantly associated with relapse. In contrast, IL-1 beta, IL-6, and tumor necrosis factor-a levels in the rectal mucosa were not associated with relapse. Conventional blood markers and plasma cytokines (IL-1 beta, IL-6, IL-8, and tumor necrosis factor-alpha) did not correlate with relapse. Among clinical factors, age and number of prior relapses were significantly associated with relapse. In multivariate analysis, a higher rectal mucosal IL-8 level ( >= 160 pg/mg of tissue; hazard ratio, 4.7), younger age (< 30 yr; hazard ratio, 7.3), and a greater number of prior relapses ( >= 5; hazard ratio, 4.3) were independent significant risk factors for future relapse. Conclusions: Rectal mucosal IL-8 measurement might be an additional objective diagnostic tool that can predict relapse in patients with quiescent UC.