Thus ERS-induced mucin depletion seems to be a relevant pathogenetic mechanism of colitis in IL-10 deficient mice; our results demonstrating a significantly reduced number of goblet cells and expression of MUC-2, IL-18, WFDC2 and Xbp-1 in IL-10 deficient mice at young ages support this hypothesis. This evidence concerns the gene XBP1 and colitis.