title: Association of interleukin-18 promoter polymorphisms with chronic obstructive pulmonary disease in male smokers.
abstract: Chronic obstructive pulmonary disease (COPD) is considered a complex genetic disorder and it is expected that many genes play a role in the pathogenesis of this disease. Previous studies have reported that several variations within the interleukin (IL)-18 gene promoter region have been associated with different inflammatory diseases such as asthma. However, the association of IL-18 promoter polymorphisms with COPD has not been studied yet. We then performed a prospective case-control study to explore this association in male smokers of Chinese Han people. Our study recruited 112 COPD cases and 105 healthy controls matched for age. The genotyping of IL-18 promoter polymorphisms (-607 C/A and -137 G/C) was performed using TaqMan single nucleotide polymorphism genotyping assays. The frequencies of the alleles and genotypes in patients and controls were compared. We found that the frequency of IL-18 -607 C allele was significantly increased in patients with COPD (odds ratio (OR) = 1.48, 95% confidence interval (CI) = 1.01-2.15, P = 0.04). The frequency of IL-18 -607 C allele was significantly higher in the GOLD (Global initiative for Obstructive Lung Disease) 3-4 group compared with the GOLD 1-2 group (OR=2.06, 95% CI = 1.21-3.51, P = 0.01). There were no significant differences in the frequencies of the alleles and genotypes of IL-18 -137 G/C polymorphism between the patients and healthy smokers or between GOLD 3-4 group and GOLD 1-2 group. Our study revealed that the IL-18 -607 C/A polymorphism was associated with COPD susceptibility and severity of airflow limitation in male smokers of Chinese Han people.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Xie
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000368:Aged; D044466:Asian People / Q000235:genetics; D016022:Case-Control Studies; D002681:China; D005787:Gene Frequency; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D020382:Interleukin-18 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012907:Smoking
chemical_list: D020382:Interleukin-18