[en] In Crohn's disease, the activity of the disease is difficult to evaluate and the evolution of the disease is difficult to predict. The soluble interleukin-2 receptor serum level has been reported to correlate with clinical activity of the disease and with mucosal immune activation. We compared serum soluble interleukin-2 receptor to classical inflammatory markers and other immune parameters in the assessment of clinical disease activity and prediction of relapse in patients with Crohn's disease. Soluble interleukin-2 receptor serum levels correlated well with the Crohn's disease activity index, and multivariate analysis showed that this correlation was independent of the other inflammatory and immune markers. The correlation was not greater, However, than that between some inflammatory markers, such as ESR, and Crohn's disease activity index. Longitudinal follow-up showed that a high soluble interleukin-2 receptor serum level was highly predictive of relapse. Multivariate analysis showed that the soluble interleukin-2 recepteur serum level was complementary to other inflammatory and clinical markers in the prediction of relapse of disease. We conclude that soluble interleukin-2 receptor is of use in monitoring Crohn's disease, particularly in prediction of relapse.