[Expression of ABH and Lewis antigens in chronic gastritis and pre-neoplasic alterations in gastric mucosa]. / Expressão dos antígenos ABH e Lewis na gastrite crônica e alterações pré- neoplásica da mucosa gástrica.

BACKGROUND: The major cause for chronic gastritis in human is the infection by the Helicobacter pylori. The blood group antigens present at the gastric mucous are described as possible receptor for this bacteria in the epithelium. The alterations in the expression of blood group patterns are associated with the development of gastric cancer. OBJECTIVES: Verify the H. pylori prevalence and examine the immunohistochemical distribution of the ABH and Lewis antigens expression to correlate with histopathological alterations. PATIENTS AND METHODS: From 63 chronic gastritis patients were investigated gastric biopsies, blood and saliva samples by dot-blot-ELISA, indirect immunoperoxidase and hematoxylin-eosin and Gram. RESULTS: No significant association between the presence of the bacteria and the ABH, Lewis and Secretor phenotype was found. For the majority of the patients the antigen expression of the ABH and Lewis blood group was restricted mainly to the foveola epithelium of the gastric mucosa, similar to the saliva. The inappropriate expression of these antigens occurred always in the presence of H. pylori and/or preneoplastic alterations of the gastric mucosa. In areas with intestinal metaplasias we also observed reduced reactivity for the H and Le b antigens and mainly the induced expression of Le . CONCLUSION: Alterations in the pattern of the glycosylation of this antigens are interesting, because they reflect different stages in the cellular differentiation and become potential markers in the diagnostic evaluation and prognosis of gastric pathologies.