Promoter polymorphism of the IL‐18 gene is associated with atopic asthma in Tunisian children

Abstract

Several lines of evidence point to a relevant role of IL-18 in the process of asthma. Some studies suggest that the polymorphism in the gene of IL-18 can be involved in many inflammatory and atopic diseases such as asthma. The aim of our study is to estimate the frequency of the IL-18-607 C/A (rs 1946518) promoter polymorphism in Tunisian children with asthma. We investigated whether the presence of this polymorphism -607 C/A was associated with asthma or atopy and whether this polymorphism influenced the severity of asthma in affected children. We examined also the relationship between the IL-18 gene polymorphism and the serum total IgE level. The IL-18/-607 C/A polymorphism was analysed by polymerase chain reaction and restriction fragment-length polymorphism (PCR-RFLP) analysis. A total of 105 asthma patients and 112 controls as part of the whole children population were studied in a case-control study. Among the 105 children with asthma, 40 were also studied for linkage analyses with their respective parents. We noted that the A allele was associated with statistically significant increases in the risk of asthma in the case-control study (odd ratio (OR) = 1.55, 95% confidence interval (CI) 1.03-2.33. Moreover, the A allele was also associated with atopic asthma (P = 0.008), but not with asthma severity. The transmission disequilibrium test (TDT) analysis in this family study did not suggest a preferential transmission of the IL-18/ -607 C/A polymorphism to affected children. There is no correlation between the IgE level and the IL-18 -607 C/A promoter polymorphism. Our data indicate that IL-18 -607 C/A promoter polymorphism is associated with susceptibility to developing asthma in Tunisian population.

The IL18 gene and Hashimoto thyroiditis in children

“…SNP rs360719A>G (À1297) is at the OCT-1 binding site [29], rs1946518T>G (À607) at a potential cyclic adenosine monophosphate (c-AMP)-responsive element-binding site [10], and rs187238G>C (À137) at a H4TF-1 nuclear factor binding site [10]. These SNPs have been reported to be individually or jointly associated with susceptibility to Crohn disease [30], inflammatory bowel disease [31], type 1 diabetes mellitus [11][12][13], renal manifestations [32] or arthritis in SLE [33], presence of anti-GAD antibody in Graves disease [34], or asthma [35,36]. However, rs1946518 alone is not associated with various autoimmune diseases including type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, Crohn disease and ulcerative colitis in a metaanalysis [37] or with autoimmune thyroid disease [38] or Graves disease [34,39] in other individual studies, nor with HT, in our study.…”

Haplotype analysis of the interleukin-18 gene in Czech patients with allergic disorders

“…Among them, Ϫ607 A/C (rs1946518), Ϫ137 C/G (rs187238) in the promoter region, and Ϫ140 C/G (previously Ϫ133 C/G, rs4988359) in intron 1 have been studied in detail with respect to etiopathogenesis of allergic diseases [15][16][17][18] and transcriptional activity or IL-18 production by monocytes [19 -21]. Current results have indicated the inconsistent association between IL-18 gene variants and clinical/ intermediary phenotypes of allergy in different populations [15][16][17][18][22][23][24][25][26][27][28][29][30][31]. However, a novel putative functional variant Ϫ1297 C/T (rs360719) within the IL-18 promoter region that seems to have an important role in IL-18 expression was recently associated with susceptibility to SLE [32].…”

Identification of IL13 C1923T as a Single Nucleotide Polymorphism for Asthma in Children from Mauritius

“…8,9 The IL-13 gene is found on chromosome 5q31-33 and has been significantly associated with allergic asthma. 10 The T allele of the IL13 C1923T and IL13 C1112T have both shown to be significantly associated with increased risk of asthma, 11,12 and rs1295686 is involved in the dysregulation of total IgE.…”