Association of Severe Respiratory Syncytial Virus Bronchiolitis with Interleukin-4 and Interleukin-4 Receptor α Polymorphisms

The association of variants of genes encoding interleukin (IL)–4 and the IL-4 receptor α chain (IL-4Rα) with respiratory syncytial virus (RSV) bronchiolitis was examined in hospitalized infants. Polymorphisms in IL-4 (C−590T) and IL-4Rα (I50V and Q551R) were genotyped by restriction fragment–length polymorphism analysis. Control subjects included parents of the hospitalized children (for the transmission/disequilibrium test), and a random population sample (for the case-control study). Results were also analyzed in a combination of these 2 tests, using Fisher’s method. The IL-4 590T allele was found more frequently among children hospitalized with RSV than expected in the case-control (odds ratio [OR], 1.43; P=.04) and combination (OR, 1.41; P=.02) tests. Among children who were >6 months old when they were hospitalized, compared with the control group or with the