title: Downregulated Th17 responses are associated with reduced gastritis in Helicobacter pylori-infected children.
abstract: Helicobacter pylori induces less gastric inflammation in children than adults. Here we investigated whether this reduced inflammation involves dysregulated T helper type 17 (Th17) responses. H. pylori-infected children and adults in Santiago, Chile had similar levels of H. pylori colonization, proportions of bacteria containing cagA and s1/s2 vacA markers of virulence, and strain genotypes (predominantly hpEurope), but the children had significantly reduced levels of gastric inflammation and neutrophil infiltration. The reduced neutrophil accumulation in the infected children was accompanied by significantly fewer gastric Th17 cells and significantly lower levels of interleukin (IL)-17-specific mRNA and protein compared with the infected adults. The gastric mucosa of H. pylori-infected children also contained higher numbers of IL-10+ cells and increased levels of both IL-10 and Foxp3 mRNA compared with that of the infected adults. Thus, reduced gastric inflammation, including diminished neutrophil accumulation, in H. pylori-infected children compared with infected adults is likely due to downregulated gastric Th17/IL-17 responses as a consequence of enhanced mucosal regulatory T-cell activity in the children.
authors.affiliation: Division of Pediatrics, Unit of Gastroenterology and Nutrition, School of Medicine, Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Serrano
authors.affiliation: Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL 35294, U.S.A.
authors.forename: Shelton W
authors.initials: SW
authors.lastname: Wright
authors.affiliation: Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL 35294, U.S.A.
authors.forename: Diane
authors.initials: D
authors.lastname: Bimczok
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Vanderbilt University, Nashville, TN 37232, U.S.A. and Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, U.S.A.
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Shaffer
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Vanderbilt University, Nashville, TN 37232, U.S.A. and Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212, U.S.A.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Cover
authors.affiliation: Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia, Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Venegas
authors.affiliation: Division of Hematology Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, U.S.A.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Salazar
authors.affiliation: Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL 35294, U.S.A.
authors.forename: Lesley E
authors.initials: LE
authors.lastname: Smythies
authors.affiliation: Division of Pediatrics, Unit of Gastroenterology and Nutrition, School of Medicine, Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Harris
authors.affiliation: Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL 35294, U.S.A.|Veterans Affairs Medical Center, Birmingham, AL 35233, U.S.A.
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D018450:Disease Progression; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005753:Gastric Mucosa / Q000276:immunology*; D005756:Gastritis / Q000209:etiology / Q000276:immunology*; D005786:Gene Expression Regulation; D016481:Helicobacter Infections / Q000150:complications / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology* / Q000472:pathogenicity; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D020381:Interleukin-17 / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology*; D037521:Virulence Factors
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D020381:Interleukin-17; D037521:Virulence Factors; D016753:Interleukin-10