Objective: To investigate the expression of co-stimulatory molecule CD86 and inducible co-stimulator(ICOS) in the intestinal mucosa of Crohn disease (CD) and to exlpore its pathologic significance.
Methods: Expression of co-stimulator CD86 and ICOS was examined by immunohistochemistry on paraffin embedded tissue from patients with CD (30 cases) and normal controls (20 cases). The subsets of lamina propria mononuclear cells (LPMC) were also analysed via immunostaining for CD4, CD8 and CD20.
Results: Increased amount of CD86 or ICOS positive LPMC was observed in the lesional area of CD when compared with the essentially normal area of CD and normal controls (q=9.23,P<0.01 and q=5.46,P<0.01). In addition, the expression of CD86 or ICOS was higher in intestinal epithelium of CD than that in normal controls(H=24.93,P<0.01 and H=4.66,P<0.01), whereas no significant difference was seen between the diseased and the essentially normal area of CD. The amount of CD4 or CD8 positive lymphocytes in lamina propria, epithelium and small vascular walls was also significantly increased in CD than that in normal controls (P<0.05 or P<0.01).
Conclusion: Increased amount of CD86 or ICOS positive LPMC and enterocytes in CD suggests that co-stimulatory molecules may play a role in the pathogenesis of CD. The enterocytes may act as non-specific antigen presenting cells in the process of cellular immunity activation in CD.