[726] Phylogeographic Origin of Helicobacter pylori Is Associated with Eosinophilic Infiltration of the Gastric Mucosa

M Blanca Piazuelo, Thibaut de Sablet, Keith T Wilson, Luis E Bravo, Barbara G Schneider, Judith Romero-Gallo, Rupesh Chaturvedi, Alberto G Delgado, Richard M Peek, Pelayo Correa. Vanderbilt University School of Medicine, Nashville; Veterans Affairs Tennessee Valley Healthcare System, Nashville; Universidad del Valle, Cali, Colombia

Background: Eosinophils participate in the immune response against H. pylori and are markers of an anti-inflammatory Th2-type response. We studied two Colombian populations with contrasting risks of gastric cancer and equally high H. pylori prevalence. The high-risk (HR) area is in the Andes Mountains, and the low-risk (LR) area on the Pacific coast. We reported that the phylogeographic origin of the H. pylori strains in these populations is associated with severity of the gastric histologic lesions. H. pylori strains of African origin were associated with less damage to the gastric mucosa than strains of European origin. We hypothesize that H. pylori strains of African ancestry may protect the gastric mucosa against cancer development by favoring a Th2 response associated with increased recruitment of eosinophils.
Design: Gastric biopsies from 80 Colombian males (40-59 years old) with H. pylori-associated gastritis were used in this study (39 from the LR area and 41 from the HR area). Eosinophils were counted in 5 high-power fields (HPF) in HE-stained sections from antral biopsies, in the areas with the highest eosinophil density. H. pylori was isolated from antral biopsies and the phylogeographic origin was determined by multilocus sequence typing.
Results: Mean values of eosinophils/HPF in the gastric mucosa were higher in the 22 subjects infected with H. pylori strains of African origin compared to the 58 subjects infected with strains of European origin (49.6 and 11.9 eosinophils/HPF, respectively; p=0.0001). Among subjects living in the LR area, those infected with African strains showed higher mean values of eosinophils/HPF compared to the subjects harboring strains of European origin.

Conclusions: Our results suggest that the recruitment of eosinophils to the gastric mucosa is partially dependent on the phylogeographic origin of the infecting H. pylori strains. However, other factors such as infection with helminths and host genetic background may also play an important role.
Category: Gastrointestinal

Monday, March 19, 2012 1:00 PM

Poster Session II # 103, Monday Afternoon


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