Identification of genes upregulated in the inflamed colonic lesions of Crohn's disease

To identify the molecular mechanism which primarily plays a role in the pat hogenesis of Crohn's disease (CD) without prior hypothesis, differential di splay method was employed to detect differentially expressed genes between the inflamed and uninflamed colonic samples from one patient with CD. The m RNA levels of these genes were subsequently semi-quantitated in affected an d unaffected tissues from six patients using reverse transcriptase polymera se chain reaction (RT-PCR). Six genes including long form FLICE inhibitory protein (FLIPL) were found to be consistently overexpressed in the inflamed colonic CD tissues. Immunohistochemical studies revealed that FLIPL expres sing cells were lamina propria lymphocytes (LPLs). The present study sugges ted that overexpression of FLIPL in the LPLs may be involved in the pathoge nesis of CD through defective activation-induced cell death. In addition, t his study provided evidence for a possible role of several previously unsus pected genes in the pathogenesis of CD. (C) 2001 Academic Press.