Ulcerative colitis and Crohn's disease: distinctive gene expression profiles and navel susceptibility candidate genes

To elucidate the biological dysregulation underlying two forms of inflammat ory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD), we examined global gene expression profiles of inflamed colonic tissue usin g DNA microarrays. Our results identified several genes with altered expres sion not previously linked to IBD. In addition to the expected upregulation of various cytokine and chemokine genes, novel immune function-related gen es such as IGHG3 IGLL2 and CD74, inflammation-related lipocalins HNL and NG AL, and proliferation-related GRO genes were over-expressed in UC. Certain cancer-related genes such as DD96, DRAL and MXI1 were differentially expres sed only in UC. Other genes over-expressed in both UC and CD included the R EG gene family and the calcium-binding S100 protein genes S100A9 and S100P. The natural antimicrobial defensin DEFA5 and DEFA6 genes were particularly over-expressed in CD. Overall, significant differences in the expression p rofiles of 170 genes identified UC and CD as distinct molecular entities. T he genomic map locations of the dysregulated genes may identify novel candi dates for UC and CD genetic susceptibility.