The expression of chemokines and the dynamics of inflammatory cell infiltration before and after H. pylori eradication

We attempted to evaluate the relationship between the expression of IL-8 and RANTES and the dynamics of their target cells in human gastric mucosa of H. pylori associated gastritis, including their changes after H. pylori eradication. We performed the measurement of the mucosal level of IL-8 and RANTES protein by ELISA and immunohistochemistry. The neutrophil infiltration into the gastric mucosa was identified by the histological examination based on the Updated Sydney system and the measurement of MPO activity. The memory T lymphocyte and eosinophil were indicated by immunohistochemistry of CD45RO that is one of surface markers indicating memory T lymphocytes and MBP that is contained in the granules of eosinophils. H. pylori positive gastric mucosa demonstrated a remarkable increase in neutrophils, CD45RO positive cells and eosinophils, compared to H. pylori negative gastric mucosa. Gastric mucosal level of IL-8 and RANTES protein and MPO activity was significantly higher in H. pylori positive cases than that in H. pylori negative controls after H. pylori eradication, both of the level of IL-8 protein and MPO activity reduced at the same levels as negative controls. However, RANTES expression, CD45RO positive T lymphocytes and eosinophils remained in H. pylori eradicated gastric mucosa at the significantly high level, compared with H. pylori negative cases. Therefore, it seems possible that IL-8 might enhance the inflammation by facilitating the neutrophil infiltration into H. pylori infected gastric mucosa and that RANTES might play an important role in the specific immune response against H. pylori and the maintenance of the immune memory after H. pylori eradication.