IL2-330G polymorphic allele is associated with decreased risk of Helicobacter pylori infection in adulthood

• Published in: Microbes and infection 2009-10, Vol.11 (12), p.980-987
• Main Authors: Queiroz, Dulciene M.M., Saraiva, Ivan E.B., Rocha, Gifone A., Rocha, Andreia M.C., Gomes, Luciana I., Melo, Fabrício F., Bittencourt, Paulo F.S.
• Format: Article
• Language: English
• Subjects: Adult; Bacteriology; Biological and medical sciences; Blood Donors; Child; Child, Preschool; Female; Fundamental and applied biological sciences. Psychology; Gene Frequency; Helicobacter Infections - genetics; Helicobacter pylori; Helicobacter pylori - immunology; Humans; IFN-γ; IL-10; IL2-330T/G; Immunity, Innate; Interferon-gamma - blood; Interleukin-10 - blood; Interleukin-2 - blood; Interleukin-2 - genetics; Interleukin-2 - immunology; Male; Microbiology; Miscellaneous; Point Mutation; Polymorphism, Genetic; Sequence Analysis, DNA; TGF-β
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2009.07.008

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-31 T → C, IL1RN allele 2, IL2-330 T → G, TNFA-307 G → A, TLR2Arg677Trp, TLR2Arg753Gln, TLR4Asp299Gly, and TLR5 392STOP polymorphisms were determined in 541 blood donors. IL2-330 T → 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-γ and IL-10/TGF-β 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-γ = 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-β = 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.