title: The association between IFN-γ and IL-4 genetic polymorphisms and childhood susceptibility to bronchial asthma.
abstract: The present study aims to investigate the association between the genetic polymorphisms of interferon (IFN)-γ and interleukin (IL)-4 with childhood susceptibility to asthma and the levels of IFN-γ, IL-4, and immunoglobulin (Ig) E among asthmatic children. A total of 100 asthmatic children and 122 control children were enrolled in the present study. The genotypes of the IFN-γ gene at the -179G/T locus and the IL-4 gene at the -33C/T and -589C/T loci were detected using polymerase chain reaction with restriction fragment length polymorphism. The IFN-γ gene at the +874A/T locus and the IFN-γ CA repeats were tested using allele-specific and capillary electrophoresis, respectively, whereas the IFN-γ, IL-4, and total IgE levels were measured using enzyme-linked immunosorbent assays. The 100 asthmatic children and the 122 control children were all GG homozygous in the -179 locus of the IFN-γ gene, which shows that the IFN-γ gene is not mutated at the -179 locus. No significant differences were found in terms of genotypic and allelic frequency distribution in the IFN-γ gene or the CA repeat at the +874A/T locus between the asthmatic children and the control (P>0.05). An association was found between the polymorphism of the IFN-γ gene at +874A/T and IFN-γ levels. IFN-γ expression was lower among patients with the AA genotype than those with the AT genotype (P<0.05); the genotypic and allelic frequency distributions of the IL-4 gene at -33C/T and -589C/T were significantly different between the asthmatic children and the control (P<0.05). The levels of IL-4 and IgE among children with TT genotype at the -33 and -589 loci were higher than those with the CT genotype, but only the polymorphism at -33C/T was associated with IL-4 levels (P<0.05). The polymorphisms of the IFN-γ gene at +874A/T or the CA repeats are not correlated with susceptibility to asthma. Thus, the polymorphism at +874A/T is correlated with IFN-γ level. The TT genotypes of the IL-4 gene at the -33 and -589 loci are associated with asthma susceptibility in children, and polymorphism at the -33 locus may be associated with IL-4 level.
authors.affiliation: Department of Pediatrics, the Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China. huaronghuangcn@126.com
authors.forename: Hua-Rong
authors.initials: HR
authors.lastname: Huang
authors.forename: Ying-Qiang
authors.initials: YQ
authors.lastname: Zhong
authors.forename: Jing-Fang
authors.initials: JF
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D007371:Interferon-gamma / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic
chemical_list: D015847:Interleukin-4; D007073:Immunoglobulin E; D007371:Interferon-gamma