IL13 and chronic obstructive pulmonary disease: Our previous data showed the T-allelic frequencies of the IL13 −1055 gene polymorphisms in COPD group are significantly higher than those in control group (18.8% versus 1.4%; p < 0.001; odds ratio [OR] = 29.3; 95% confidence interval [CI]: 5.9–145.3); and the frequencies of CT/TT genotypes in COPD group are significantly higher than those in control group (27.1% versus 2.8%; p < 0.001; OR = 20.0; 95% CI: 3.9–100.8); and IL13 −1055 T allele is the independent factor associated with forced expiratory volume in 1 s (p = 0.007) [10].