High contribution contrast between the genes of eosinophil peroxidase and IL-4 receptor α-chain in Japanese cedar pollinosis

Background: Japanese cedar pollinosis is the most common form of hayfever in Japan in spring and has remarkably increased since 1960. Objective: We sought to clarify the candidate genes for cedar pollinosis using a case-control study. Methods: After diagnosing 351 subjects on the basis of an intradermal test, nasal provocation test, and questionnaire regarding nasal and conjunctival symptoms, we determined the blood-specific IgE values and genotypes of eosinophil peroxidase (EPO) and interleukin-4 receptor α-chain (IL4RA) in 145 patients with pollinosis and 206 healthy subjects, including 75 healthy subjects with higher specific IgE values. Results: We found significant differences in the frequencies of Pro358Leu in EPO and of Ile50Val and Glu375Ala in IL4RA between patients and healthy subjects. There was a significant-ly higher frequency of 358Leu in EPO in patients than in healthy subjects showing a higher specific IgE value. In contrast, we recognized significant changes in the prevalence of Ile50Val and Glu375Ala in IL4RA in healthy subjects with a normal IgE value compared with those in healthy subjects with a higher specific IgE value. The relationship between EPO polymorphisms and the onset of symptoms was exactly opposite that for IL4RA. Conclusions: These results suggest that Pro358Leu in EPO is strongly involved in the development of cedar pollinosis. Ile50Val and Glu375Ala in IL4RA seem to be related to cedar pollen sensitization. Subjects with Ile50 or Glu375 might develop cedar pollinosis with increased exposure to cedar pollen.