Characterization of lymphocytic infiltrates in Helicobacter pylori-associated gastritis.

This study evaluated the specific subset composition of lymphocytes present in Helicobacter pylori-associated gastritis (HAG), since reports so far have led to inconclusive and conflicting results. Endoscopic biopsy specimens from 56 patients were studied by quantitative immunohistochemistry using monoclonal antibodies against the lymphocyte markers CD3, CD22, CD4, CD8, CD45RO, CD1O3, TCR alpha/beta, and TCR gamma/delta. Lamina propria and intraepithelial compartments were evaluated separately. Grade, activity, and density of bacterial colonisation were assessed histologically and with Warthin-Starry stain. Evaluation showed a significant increase in CD4+, CD45RO+, TCR alpha/beta+ activated lamina propria lymphocytes in HAG which correlated with grade and activity of gastritis and degree of bacterial colonisation, whereas subsets of intraepithelial lymphocytes did not change significantly. TCR gamma/delta+ T cells were not found to be increased in HAG. Selective expansion of CD4+, CD45RO+ memory-type T cells could reflect an antigen-specific and/or chemokine-mediated effect in HAG. Locally produced CC chemokines such as RANTES have been detected in HAG.