ABSTRACT
PURPOSE: Cysteinyl leukotrienes are important proinflammatory mediators in asthma. Recently, it was suggested that a promoter polymorphism in the genes encoding for leukotriene C4 synthase (LTC4S), a key enzyme in the leukotriene synthetic pathway, and cysteinyl leukotriene receptor 1 (CysLTR1) might be associated with aspirin-intolerant asthma. We investigated whether polymorphisms in LTC4S and CysLTR1 genes or their interactions were associated with the asthma phenotype, lung function, or bronchial hyperreactivity (BHR) in Korean children. METHODS: A total of 856 asthmatic children and 254 non-asthmatic controls were enrolled; a skin prick test, lung function test and bronchial provocation test were performed. Of those enrolled, 395 children underwent exercise challenge tests. The LTC4S A(-444)C and CysLTR1 T(+927)C were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: Of those enrolled, 699 children were classified as having atopic asthma and 277 children, as having exercise-induced asthma (EIA). LTC4S and CysLTR1 polymorphisms were not associated with atopic asthma, EIA, or asthma per se. Lung function and BHR were not significantly different between the wild type (AA or TT) and the variant (AC+CC or TC+CC) genotypes in asthmatics, atopic asthmatics, and EIA (+) asthmatics, while total eosinophil counts were higher in the variant type of LTC4S than in the wild type in atopic asthmatics. There were no associations between the gene-gene interactions of LTC4S and CysLTR1 genotypes and the asthma phenotypes. CONCLUSION: LTC4S A(-444)C and CysLTR1 T(+927)C polymorphisms and their gene-gene interactions are not associated with asthma phenotype, lung function, or BHR in Korean children.