title: IL2-330G polymorphic allele is associated with decreased risk of Helicobacter pylori infection in adulthood.
abstract: We evaluated whether polymorphisms in genes coding molecules linked to the innate and adaptive immune response are associated with susceptibility to Helicobacter pylori infection. IL1B-511C-->T, IL1B-31T-->C, IL1RN allele 2, IL2-330T-->G, TNFA-307G-->A, TLR2Arg677Trp, TLR2Arg753Gln, TLR4Asp299Gly, and TLR5(392STOP) polymorphisms were determined in 541 blood donors. IL2-330T-->G allele carriers had a decreased H. pylori infection risk (OR=0.63, 95% CI=0.43-0.93) after adjustment for demographic and environmental factors. Hence, we investigated whether the polymorphism is functional by evaluating IL-2 serum concentration in 150 blood donors and 100 children. IL-2 pro-inflammatory and anti-inflammatory properties were indirectly investigated by determining serum IFN-gamma and IL-10/TGF-beta levels. The polymorphism was associated with increased mean IL-2 levels in H. pylori-positive adults (2.65 pg/mL vs. 7.78 pg/mL) and children (4.19 pg/mL vs. 8.03 pg/mL). Increased IL-2 was associated with pro-inflammatory activity in adults (IFN-gamma=18.61 pg/mL vs. 25.71 pg/mL), and with anti-inflammatory activity in children (IL-10=6.99 vs. 14.17 pg/mL, TGF-beta=45.88 vs. 93.44 pg/mL) (p<10(-3) for all). In conclusion, in the context of H. pylori infection, IL2-330 T-->G polymorphism is functional and is associated with decreased risk of infection in adults.
authors.affiliation: Laboratory of Research in Bacteriology, Faculdade de Medicina, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190/216 - 30130-100, Belo Horizonte, Brazil. dqueiroz@medicina.ufmg.br
authors.forename: Dulciene M M
authors.initials: DM
authors.lastname: Queiroz
authors.forename: Ivan E B
authors.initials: IE
authors.lastname: Saraiva
authors.forename: Gifone A
authors.initials: GA
authors.lastname: Rocha
authors.forename: Andreia M C
authors.initials: AM
authors.lastname: Rocha
authors.forename: Luciana I
authors.initials: LI
authors.lastname: Gomes
authors.forename: Fabrício F
authors.initials: FF
authors.lastname: Melo
authors.forename: Paulo F S
authors.initials: PF
authors.lastname: Bittencourt
mesh_terms: D000328:Adult; D001782:Blood Donors; D002648:Child; D002675:Child, Preschool; D005260:Female; D005787:Gene Frequency; D016481:Helicobacter Infections / Q000235:genetics*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D007371:Interferon-gamma / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D007376:Interleukin-2 / Q000097:blood / Q000235:genetics* / Q000276:immunology; D008297:Male; D017354:Point Mutation; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
chemical_list: C508594:IL2 protein, human; D007376:Interleukin-2; D016753:Interleukin-10; D007371:Interferon-gamma