As the NK cell receptor KIR2DL4 has been reported to induce interferon gamma (IFNγ) secretion when ligated with HLA-G, we postulated that the 9A/10A genetic polymorphism of KIR2DL4 which influences receptor structure may influence susceptibility to asthma.
We selected the IFNG locus on 12q21 as a candidate gene for asthma on the basis of its role in pathophysiology and positive linkage demonstrated in other populations.
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).
This study investigated CA repeats polymorphism of the IFN-gamma gene and GT repeats polymorphism of the IRF-1 gene, which may predispose individuals to asthma pathogenesis.
Affected sib-pair analysis revealed significant evidence for linkage to asthma over approximately 30 cM (P <.05 to.002), with the best evidence for linkage at a CA repeat polymorphism in the first intron of IFNG in 12q21.1 (P =.002).
Interferon-gamma (IFNgamma) is located on chromosome 12, and a number of studies have detected very strong linkage signals around this gene and asthma.
Interferon-gamma (IFNgamma) is located on chromosome 12, and a number of studies have detected very strong linkage signals around this gene and asthma.
Chromosome 12q13-24 is among the regions most frequently identified in genome-wide surveys for asthma susceptibility loci, with reports of two distinct clusters of positive linkage signals: one near the interferon gamma locus, the other near the nitric oxide synthase 1 locus.
We selected the IFNG locus on 12q21 as a candidate gene for asthma on the basis of its role in pathophysiology and positive linkage demonstrated in other populations.
C. pneumoniae-induced IFN-γ production in vitro was more prevalent in asthma compared with non-asthma; levels of IFN-γ were higher in asthma compared with non-asthma (P = 0.003).
The characterization of CCR10<sup>+</sup> ILC2s in human samples and in mouse asthma models suggests that these cells downregulate allergic inflammation through IFN-γ production.
Using these approaches, studies have suggested that genes within the cytokine gene cluster on chromosome 5 (including interleukins-3, -4, -5, -9, and -13), chromosome 11 (the beta chain of the high affinity IgE receptor), chromosome 16 (the IL-4 receptor), and chromosome 12 (stem cell factor, interferon-gamma, insulin growth factor, and Stat 6 [IL-4 Stat]) may contribute to asthma and allergy development.