title: Serologic evidence that ascaris and toxoplasma infections impact inflammatory responses to Helicobacter pylori in Colombians.
abstract: BACKGROUND
  Helicobacter pylori-infected children from coastal Tumaco, Colombia, have more parasitism, and adults have lower gastric cancer risk compared with high-altitude Pasto/Tuquerres residents. Because helminth and Toxoplasma gondii infections alter helicobacter gastritis in rodent models, we determined whether seropositivity to Ascaris lumbricoides or T. gondii was associated with Th2-IgG1 or Th1-IgG2 responses to H. pylori.
  
  
  METHODS
  Sera (240) from the two populations were evaluated for A. lumbricoides and T. gondii seropositivity and results correlated with IgE and IgG isotype responses to H. pylori.
  
  
  RESULTS
  Most Tumaco children and adults were seropositive for A. lumbricoides (89%, 66%), T. gondii (59%, 98%), or both (45%, 66%). In contrast, seropositivity among Pasto/Tuquerres children was much lower (9%A. lumbricoides, 11%T. gondii, and 2% dual positive) but increased in adults (58%A. lumbricoides, 82%T. gondii, and 41% dual positive). A. lumbricoides seropositivity correlated with elevated IgE and anti-inflammatory Th2-IgG1 responses to H. pylori, while T. gondiigondii seropositivity was linked to elevated IgE, pro-inflammatory Th1-IgG2, IgG3, and IgG4 responses to H. pylori. Individuals with high T. gondii titers had reduced Th1-IgG2, IgG3, and IgG4 responses to H. pylori.
  
  
  CONCLUSIONS
  Results support regional differences for childhood parasitism and indicate A. lumbricoides and T. gondii infections may impact inflammatory responses to H. pylori and partially explain differences in gastric cancer risk in Colombia.
authors.affiliation: Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Courtney
authors.initials: C
authors.lastname: Ek
authors.forename: Mark T
authors.initials: MT
authors.lastname: Whary
authors.forename: Melanie
authors.initials: M
authors.lastname: Ihrig
authors.forename: Luis E
authors.initials: LE
authors.lastname: Bravo
authors.forename: Pelayo
authors.initials: P
authors.lastname: Correa
authors.forename: James G
authors.initials: JG
authors.lastname: Fox
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D000913:Antibodies, Protozoan / Q000276:immunology; D001196:Ascariasis / Q000150:complications / Q000276:immunology* / Q000469:parasitology; D001200:Ascaris / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003105:Colombia; D005260:Female; D016481:Helicobacter Infections / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000502:physiology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007223:Infant; D008297:Male; D008875:Middle Aged; D014122:Toxoplasma / Q000502:physiology*; D014123:Toxoplasmosis / Q000150:complications / Q000276:immunology* / Q000469:parasitology
chemical_list: D000909:Antibodies, Helminth; D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M