Association between a TGFbeta1 promoter polymorphism and rhinosinusitis in aspirin-intolerant asthmatic patients.

BACKGROUND: Rhinosinusitis is highly associated with aspirin-intolerant asthma (AIA). The risk of aspirin intolerance is higher in people with rhinosinusitis than in those without it. Recently, the role of transforming growth factor beta1 (TGFbeta1) in the pathogenesis of chronic rhinosinusitis has come under investigation. The goal of this study was to evaluate the association of TGFbeta1 gene polymorphism with an AIA phenotype in the Korean population.

METHODS: A promoter polymorphism of the TGFbeta1 gene, TGFbeta1-509C>T, and a coding polymorphism (L10P), were genotyped in 203 patients with AIA, 324 patients with aspirin-tolerant asthma (ATA), and 456 normal controls (NC). Serum TGFbeta1 levels were determined by ELISA.

RESULTS: The TGFbeta1-509C>T polymorphism was not significantly associated with the AIA phenotype; however, a significant association with the prevalence of rhinosinusitis in AIA (P=0.012), but not in ATA (P>0.05), was observed. When stratified by the presence of rhinosinusitis, the frequency of T allele carriers (CT or TT genotype) of TGFbeta1-509C>T was significantly higher in AIA (87.1%) compared to ATA (52.9%, P<0.001, OR=6.0, 95% CI=3.3-11.1). In addition, AIA patients carrying the TGFbeta1-509T allele showed a lower serum TGFbeta1 level compared to AIA patients carrying the TGFbeta1-509 CC genotype, especially when stratified by the presence of rhinosinusitis (P=0.002).

CONCLUSION: Our results show that the TGFbeta1 polymorphisms are not associated with the AIA phenotype in the Korean population, but may contribute to the development of the AIA phenotype with rhinosinusitis.