Background: Recently, we have shown that both antioxidant and oxidant genes are proper candidates for asthma susceptibility genes.
Objectives: In the present study we investigated whether a common polymorphism -463G > A in the promoter of myeloperoxidase (MPO) gene, an enzyme producing hypohalogenic oxidants, is associated with the risk of bronchial asthma.
Methods: We studied 429 unrelated Russian subjects including 215 asthmatic patients and 214 sex- and age-matched healthy controls from Central Russia. The genotyping of the polymorphism -463G > A in the MPO gene was performed by the polymerase chain reaction and the restriction fragment length polymorphism assays.
Results: It was found that a carriage of a -463A allele is associated with decreased risk of asthma (OR 0.64 95%CI 0.44-0.91, p = 0.013). Furthermore, variant genotypes (-463GA + AA) of the MPO gene were associated with decreased risk of asthma (OR adjusted by age, gender, and immunoglobulin E (IgE) level was 0.63 95%CI 0.42-0.95), but at a borderline statistical significance (Bonferroni corrected p = 0.017). Further analysis revealed that both a -463A allele and the -463GA/AA genotypes are significantly associated with decreased risk of atopic asthma (p = 0.01). No association of the -463G > A polymorphism of the MPO gene with non-atopic asthma has been revealed. We also found that the allele -463A (OR = 0.47 95%CI 0.27-0.81, p = 0.01) and the -463GA + AA genotypes (OR 0.43 95%CI 0.24-0.78, p = 0.005) are significantly associated with decreased risk of late-onset atopic asthma (the disease onset after 30 years). No association of both allele and genotypes of the polymorphism -463G > A of the MPO gene with early-onset of atopic and non-atopic asthma (the disease before 30 years) was seen.
Conclusions: The results of this study provide novel insights into pathogenesis of bronchial asthma. We put forward a suggestion about a possible mechanism by which the -463G > A polymorphism of the MPO gene is involved into pathogenesis of asthma.