The Differences in the Involvements of Loci of Promoter Region and Ile50Val in Interleukin-4 Receptor α Chain Gene between Atopic Dermatitis and Japanese Cedar Pollinosis

ABSTRACTBackgroundAtopic dermatitis (AD) and Japanese cedar pollinosis (JCP) are common chronically allergic diseases associated with the activation of T-helper 2 cells. Recent studies have shown that polymorphisms in the genes for IL-4 receptor α chain (IL4RA) may contribute to susceptibility of AD and JCP, although the differences in the involvements of loci of IL4RA gene between AD and JCP are unclear. In this study, we investigated the role of polymorphisms in IL-4RA gene in conferring susceptibility to the development of AD and/or JCP using a family analysis and an association analysis in a Japanese population.MethodsFive polymorphisms in the IL-4RA gene, C-3223T, T-1914C, T-890C, Ile50Val and Glu375Ala, have been genotyped using PCR-based methods in 75 trios families, including 15AD families, 30 JCP families, and 30 families with combination of AD and JCP in the family analysis. Forty-five AD, 60 JCP and 125 control children constituted the association study.ResultsThe transmission disequilibrium test showed that the allele of Ile50 was significantly transmitted to children with JCP alone (p<0.05). Haplotype analysis showed that the -3223T/Ile50 haplotype was preferentially transmitted to both AD (p<0.01) and JCP children (p<0.01), while that the C-3223/Ile50 haplotype was preferentially transmitted to only JCP children (p