Polymorphisms of IL4, IL13, and ADRB2 genes in COPD.

Study objectives: Interleukin (IL)-4, IL-13, and β 2 -adrenoceptor (ADRB2) are involved in airway hyperresponsiveness (AHR), and their coding genes are located on chromosome 5q31-q33. AHR is one of the risk factors for COPD. Investigating polymorphisms within these genes may help to pinpoint the genetic susceptibility to COPD. Subjects and measurements: A case-control association study was conducted on two different ethnic groups: Japanese subjects (88 patients with COPD and 61 control subjects) and Egyptian subjects (106 patients with COPD and 72 control subjects). The following polymorphisms were genotyped: − 589 C/T, − 33 C/T, and variable number of tandem repeat (VNTR) in IL4 , − 1111 C/T and + 2044 G/A in IL13 , and + 46 A/G and + 79 C/G in ADRB2 . Pairwise haplotype frequencies as well as genotype and allele frequencies were analyzed. Results: The distribution of the genotype frequencies of ADRB2 + 79 C/G was significantly different between the COPD and the control groups in the Egyptians (p = 0.002). The distributions of the haplotypes in the Japanese ( IL4 − 589 C/T: IL4 VNTR; IL4 − 33 C/T: IL4 VNTR) [corrected p values IL4 − 589 C/T: ADRB2 + 79 C/G; IL4 VNTR: ADRB2 + 79 C/G) [corrected p values, 0.033 and 0.001, respectively] showed significant differences between the COPD and the control groups. Conclusions: The ADRB2 + 79 C/G polymorphism and the haplotypes shown in this study may be involved in the pathogenesis of COPD.