title: The synergistic effects of the IL-9 gene and environmental exposures on asthmatic Taiwanese families as determined by the transmission/disequilibrium test.
abstract: Asthma occurs in genetically susceptible individuals in the presence of environmental factors. The interleukin-9 (IL-9) gene, one of the cytokine genes located on chromosome 5q31, plays an important role in the development of asthmatic syndrome by enhancing both T-cell and mast-cell function. This study investigated GT repeat polymorphism of the IL-9 gene and the gene-environment interactions, which may predispose individuals to asthma and atopy pathogenesis. In this study, we used the transmission/disequilibrium test (TDT) to investigate the relationship between asthma and the IL-9 gene by studying 123 parent-offspring trios and 91 siblings. For allele-specific TDT chi-squared test, allele 122 of the IL-9 gene showed significant association with asthmatics with specific IgE against house dust (HD) (P = 0.038). The additions of covariates to TDT to conduct the synergistic effects between the IL-9 gene and environmental factors into account were estimated by conditional logistic regression models. The odds ratio for transmission of allele 122 of the IL-9 gene was 1.23 (P = 0.28) for all asthmatic probands. There was slight increased interaction effect on asthma between transmission of allele 122 of IL-9 gene to offspring and who were exposed to the fur of pets (OR = 3.33, P = 0.047). We also detected elevated odds of transmission of allele 122 to atopic asthmatic probands (OR = 2.08, P = 0.03) and offspring with very high levels of serum IgE (> or = 800 IU mL(-1)). In conclusion, this study has found that the IL-9 gene was slightly associated with asthmatics who have positive specific IgE against Der p (or Der f) and house dust, when information on environmental factors was incorporated as effect modifiers.
authors.affiliation: Faculty of Public Health, Kaohsiung Medical University, 100 Shih-Chuan 1 Road, Kaohsiung, Taiwan.
authors.forename: T-N
authors.initials: TN
authors.lastname: Wang
authors.forename: W-Y
authors.initials: WY
authors.lastname: Chen
authors.forename: Y-F
authors.initials: YF
authors.lastname: Huang
authors.forename: N-H
authors.initials: NH
authors.lastname: Shih
authors.forename: W-W
authors.initials: WW
authors.lastname: Feng
authors.forename: H-I
authors.initials: HI
authors.lastname: Tseng
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.forename: Y-C
authors.initials: YC
authors.lastname: Ko
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000235:genetics* / Q000276:immunology*; D002648:Child; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D016906:Interleukin-9 / Q000235:genetics* / Q000502:physiology; D008297:Male; D013624:Taiwan
chemical_list: C508607:IL9 protein, human; D016906:Interleukin-9