Chemokine production by buccal epithelium as a distinctive feature of pediatric Crohn disease

OBJECTIVES: Inflammatory bowel diseases (IBD) represent an aberrant immune response by the mucosal immune system to luminal bacteria. Because the oral mucosa harbors the first epithelial cells that interact with microorganisms, we assessed the immunologic activity of buccal epithelium in children with IBD and adults with Crohn disease.

METHODS: Buccal epithelial cells were obtained from 17 children and 14 adults with Crohn disease, 18 children with ulcerative colitis, and 40 controls. Cells were cultured with and without microbial stimulation. Chemokine levels were determined in culture supernatants by cytometric bead array and enzyme-linked immunoabsorbent assay. CXCL-8 production was studied by immunohistochemical analysis of these cells. CXCL-8 production by lipopolysaccharide stimulated monocyte-derived dendritic cells from these patients was determined.

RESULTS: Compared with controls, pediatric ulcerative colitis patients, and adult Crohn disease patients, only in children with Crohn disease did buccal epithelial cells exhibit enhanced production of CXCL-8, CXCL-9, and CXCL-10. In vitro stimulation with lipopolysaccharide or zymosan resulted in a further increase of chemokine levels only in cells from pediatric Crohn disease patients. CXCL-8 production by stimulated monocyte-derived dendritic cells from children with Crohn disease was equal to that of children with ulcerative colitis.

CONCLUSIONS: Buccal epithelium of children with Crohn disease is immunologically active, even in the absence of oral lesions. The enhanced chemokine production is associated with pediatric Crohn disease and appears restricted to cells derived from the epithelial barrier. Assessment of chemokine production by buccal epithelial cells may become a new, rapid, noninvasive test for screening and classification of IBD in children.