Polymorphisms in the IL-4 and IL-4R [alpha] genes and allergic asthma.

Abstract

Allergic asthma is caused by genetic and environmental factors that interact to determine disease susceptibility and severity. Several lines of evidence suggest that the interleukin (IL-4 gene and the IL-4-receptor alpha (IL-4Ralpha) gene are involved in the development of atopic diseases. We sought to determine whether two polymorphism sites in IL-4 and IL-4Ralpha chain were associated with allergic asthma in a Chinese population. We obtained DNA and clinical data from allergic asthma patients, which were compared with those of a group of healthy control subjects. The subjects were genotyped for the IL-4 C-590T promoter polymorphism and the IL-4R alpha chain Q576R by polymerase chain reaction-restriction fragment length polymorphism. The results showed that the IL-4 C-590T was not associated with allergic asthma in a Chinese population. However, the IL-4R alpha chain 576R/R was significantly increased in allergic asthma patients compared with control subjects (chi2 = 21.16; p < 0.01), and also total plasma immunoglobulin E (IgE) level was increased in allergic asthma patients. These data suggest that the IL-4R alpha chain 576R/R genotypes confer genetic susceptibility to allergic asthma in Chinese.