title: IL-5 Promoter Polymorphism Enhances IgE Responses to Staphylococcal Superantigens in Adult Asthmatics.
abstract: Interleukin 5 (IL-5) is a key cytokine involved in the induction of T-helper type 2 (Th2) responses in the asthmatic airway. We investigated IL-5 genetic polymorphisms associated with asthma phenotypes, including IgE responses to staphylococcal enterotoxins A and B (SEA and SEB, respectively), in asthmatics. Adult asthmatics (n=310) and normal controls (n=160) were enrolled in the present study. Serum total and specific IgE to SEA and SEB were measured. Two IL-5 polymorphisms, -746A>G and +4499T>G, were genotyped using the primer-extension method. There were no significant differences in genotype or haplotype frequencies of these polymorphisms between the two groups. Asthmatics carrying the AG/GG genotype at -746A>G had a significantly higher prevalence of serum specific IgE to SEA (P=0.008), higher total IgE levels (P=0.014), and lower PC20 methacholine levels (P=0.002) compared to those with the AA genotype. These findings suggest that the IL-5 promoter polymorphism at -746A>G enhances serum total and specific IgE responses to SEA, which may augment airway hyperresponsiveness in adult asthmatics.
authors: Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
authors: Purevsuren
authors: P
authors: Losol
authors: Seung-Hyun
authors: SH
authors: Kim
authors: Eui-Kyung
authors: EK
authors: Hwang
authors: Yoo Seob
authors: YS
authors: Shin
authors: Hae-Sim
authors: HS
authors: Park
keywords: Asthma; IL-5; eosinophilic inflammation; polymorphism; staphylococcal enterotoxin