Search

The C-509T polymorphism of TGF-beta(1) gene has been associated with asthma and atopy in white populations.We investigated the association between asthma and previously identified polymorphisms at C-509T and T869C of the TGF-beta(1) gene among 250 Chinese patients with asthma and 308 healthy controls in Hong Kong.Genotyping was performed on peripheral blood genomic DNA by using PCR-RFLP.There were no differences in the frequencies of genotypes and alleles between patients and controls. The C-509T and T869C polymorphisms were in tight linkage disequilibrium (P.01). Among atopic subjects, significant differences were found in genotype and allele frequencies for T869C polymorphism between patients and controls (P = .014 and P = .019, respectively), and individuals bearing the CC genotype were associated with increased risk for the development of asthma (odds ratio, 2.58; 95% CI, 1.17-5.66; P = .018) after adjusting for age, sex, and smoking status. Individuals with asthma bearing the CT genotype of the C-509T polymorphism had significantly increased risk for severe airflow obstruction compared with individuals who had mild obstruction (odds ratio, 4.00; 95% CI, 1.06-15.08; P = .035).Our results indicate that the polymorphisms at C-509T and T869C of the TGF-beta(1) gene are associated with asthma susceptibility in atopic subjects of the Hong Kong Chinese population, and the C-509T polymorphism may play a role in the pathogenesis of airflow obstruction.

Patients with asthma generate an increased amount of reactive oxygen species from peripheral blood cells. Reactive oxygen species produce many of the pathophysiologic changes associated with asthma and may contribute to its pathogenesis.We investigated changes in antioxidant enzyme activities and oxidized glutathione (glutathione disulfide; GSSG) levels in erythrocytes from a group of healthy control Chinese subjects (n=135) and patients with asthma (n=106).Baseline pulmonary function was measured for all subjects. Antioxidant status was evaluated by measuring erythrocyte superoxide dismutase, catalase, and glutathione peroxidase activities. Oxidative stress was also measured in terms of GSSG in erythrocytes with a kinetic microassay.Patients with asthma had significantly increased erythrocyte superoxide dismutase and catalase activities compared with controls (61.10 +/- 1.30 U/g hemoglobin [Hb] vs 55.51 +/- 1.82 U/g Hb [P=.018] and 0.0637 +/- 0.0021 U/g Hb vs 0.0257 +/- 0.0120 U/g Hb [P.001] for the asthma and control groups, respectively). Conversely, erythrocyte glutathione peroxidase activity decreased (44.21 +/- 1.33 mU/g Hb vs 50.07 +/- 1.39 mU/g Hb for the asthma and control groups, respectively; P=.003). Patients with asthma also had significantly higher GSSG levels in erythrocyte hemolysates compared with controls (167.40 +/- 2.93 micromol/L vs 44.98 +/- 0.44 micromol/L for the asthma and control groups, respectively; P.001), indicating increased oxidative stress.Asthma is accompanied by an alteration in systemic antioxidant status due to possible oxidative stress in this disease.