Expression of cell membrane complement regulatory glycoproteins along the normal and diseased human gastrointestinal tract.
OBJECTIVE
Uncontrolled complement activation may be of immunopathological importance in inflammatory diseases of the gastrointestinal tract. Expression of membrane bound factors that regulate complement activation was therefore studied in situ.


METHODS
Frozen tissue specimens were obtained from patients with Helicobacter pylori gastritis, coeliac disease, Crohn's disease, or ulcerative colitis, and from histologically normal controls. Sections were examined by immunofluorescence with monoclonal antibodies to protectin (CD59), decay accelerating factor (DAF), and membrane cofactor protein (MCP).


RESULTS
Protectin and MCP were widely expressed in normal and diseased mucosae. MCP was generally observed basolaterally on all epithelial cells, whereas apical protectin expression was more intense on the epithelium of normal colonic mucosa than in the normal duodenum (p = 0.001). Epithelial DAF and to some extent protectin were upregulated in gastritis, coeliac disease, and inflammatory bowel disease. Areas of the stomach with intestinal metaplasia expressed DAF, unlike the adjacent gastric epithelium. Parietal cells of the gastric body expressed neither protectin nor DAF.


CONCLUSIONS
Epithelial complement inhibitory molecules were expressed differently at various normal gastrointestinal sites and also in association with mucosal disease, suggesting variable protective potential. Such molecules could play a role in the development of gastric atrophy by protecting areas of intestinal metaplasia. Conversely, parietal cells appeared to be potentially vulnerable targets for complement attack.
Berstad
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AE
Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, National Hospital, Rikshospitalet, Norway.
Brandtzaeg
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P
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D018958:CD55 Antigens / Q000032:analysis; D018957:CD59 Antigens / Q000032:analysis; D003169:Complement Inactivator Proteins / Q000032:analysis*; D004848:Epithelium / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D005753:Gastric Mucosa / Q000276:immunology*; D005767:Gastrointestinal Diseases / Q000276:immunology*; D016481:Helicobacter Infections / Q000276:immunology; D016480:Helicobacter pylori; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology*; D008297:Male; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000032:analysis; D008875:Middle Aged; D018709:Statistics, Nonparametric
D015703:Antigens, CD; D015415:Biomarkers; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; D003169:Complement Inactivator Proteins; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins