Objective: To study the frequencies of interleukin-13 (IL-13) gene promoter 1055 (IL-13-1055) polymorphism in patients with chronic obstructive pulmonary disease (COPD) and to investigate the effect of this genetic polymorphism on COPD in Chinese.
Methods: The polymorphism in 111 COPD patients and 97 controls who had non-obstructive pulmonary disease were studied. Genomic DNA was extracted from peripheral blood mononuclear cells by using standard high-concentration salt method. Genomic DNA was used as a template for amplification by polymerase chain reaction (PCR)-amplification of specific allele (PASA) to determine the polymorphism at -1055 in the IL-13 gene promoter region. The production was investigated by sequence analysis. SPSS was used for statistical analysis. chi(2) test was used to examine the genotype in COPD patients and controls. Logistic regression analysis was used to exclude confounding factors and evaluate the effect of smoking or family history on COPD combining with gene polymorphism.
Results: The frequency of TT genotype in COPD was 11.7% (13/111), and 13.4% (13/97) in control group, P = 0.713. P value was increased to 0.244 using logistic regression analysis excluded confounding factors, including age, gender, smoking and combined diseases. TT genotype can increase the risk of smoking to COPD, OR = 6.40 (95% CI: 1.62 - 25.39) when the data was stratified by smoking status. TT genotype was positively related with family history of COPD, OR = 7.67 (95% CI: 1.37 - 43.80) using multiple factors regression analysis to clinic phenotype and TT genotype.
Conclusion: TT genotype of IL-13-1055 is not an independent factor for COPD in Chinese Han people in Beijing, but increases the risk for smokers to develop COPD and the one who has COPD family history as well.