title: IL-4 Receptor α Polymorphisms May Be a Susceptible Factor for Work-Related Respiratory Symptoms in Bakery Workers.
abstract: OBJECTIVE
  The IL-4 and IL-4 receptor α (IL-4Rα) genes are the key candidate genes for atopy and asthma susceptibility. Exposure to wheat flour can cause IgE sensitization and respiratory symptoms in bakery workers. Therefore, we hypothesized that IL-4 and IL-4Rα single nucleotide polymorphisms (SNPs) may be involved in the pathogenic mechanism of baker's asthma.
  
  
  METHODS
  Clinical and genetic data from 373 bakery workers were analyzed. A survey questionnaire, spirometry, and skin prick tests with wheat flour were performed. Serum-specific IgE, IgG1, and IgG4 to wheat flour were determined using ELISA. Five candidate IL-4 (-729 T>G, 589 T>C, and 33 T>C) and IL-4Rα (Ile75Val A>G and Gln576Arg A>G) SNPs were genotyped and analyzed.
  
  
  RESULTS
  Workers with the G allele of IL-4Rα Ile75Val A>G had a significantly higher prevalence of work-related lower respiratory symptoms than those with the AA genotype (P=0.004, 16.0% vs. 2.9%). In the skin prick test, workers with the AA genotype of IL-4Rα Gln576Arg A>G had a significantly higher positive rate to wheat flour (P=0.015, 8.2% vs. 1.1%) than those with AG/GG genotype. No significant associations were found in the three genetic polymorphisms of IL-4. For the predicted probabilities, workers with the AA genotype of Gln576Arg A>G had a higher prevalence of IgG1 and IgG4 in response to wheat flour, according to increased exposure intensity (P=0.001 for IgG1 and P=0.003 for IgG4).
  
  
  CONCLUSIONS
  These findings suggest that the IL-4Rα Ile75Val and Gln576Arg polymorphisms may be associated with work-related respiratory symptom development.
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
authors.forename: Gyu-Young
authors.initials: GY
authors.lastname: Hur
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Ye
authors.forename: Dong-Hee
authors.initials: DH
authors.lastname: Koh
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Hae-Sim
authors.initials: HS
authors.lastname: Park
keywords: Genetic polymorphism; IL-4; IL-4 Receptor α; baker's asthma; work-related symptom