IS THE SANCTUARY WHERE HELICOBACTER-PYLORI AVOIDS ANTIBACTERIAL TREATMENT INTRACELLULAR

The sanctuary site where Helicobacter pylori evades antimicrobial ther apy is unknown, but considerable data exist about an intracellular loc ation for H pylori. Ten H pylori-infected volunteers received standard triple antimicrobial therapy for 2 weeks. Gastric mucosal biopsy spec imens were obtained with jumbo forceps on therapy days 0, 3, 14, and 4 2. Hematoxylin-eosin shining was used for classification of gastritis and the Gents stain for the visualization of H pylori. Immunohistochem ical staining was used to detect HLA-DR antigens, human heat shock pro tein (HSP60), and the bacterial HSP60 antigen. Bacterial HSP60 was exp ressed on the mucosal surface and within epithelial cells. No such exp ression of human HSP60 was found, which supports a bacterial origin fo r the intracellular HSP60. Coexpression of bacterial HSP60 and HLA-DR was always observed, indicating an ongoing local immune response. infe ction was cleared on day 14, but when examined 4 weeks after completio n of therapy, Genta staining indicated that only five volunteers remai ned free of H pylori. However, results of immunohistochemical staining were negative at this time for only two volunteers. Disappearance of intracellular expression of bacterial HSP60 remained after therapy and correlated with the intensity of chronic inflammatory cell infiltrati on. These data are consistent with the intracellular localization of H pylori having a role in inflammation and as a protective strategy aga inst extracellular antibacterial activity.