Abstract
PURPOSE: T cells play a central role in cell-mediated immunity, atopic disease, and asthma. The balance of CD28/cytotoxic T-lymphocyte antigen 4 (CTLA4)-derived signal transduction plays an important role in the activation of T cells and an increased immunoglobulin E (IgE) response. The aim of the current study was to investigate the association between polymorphisms in the genes encoding both CTLA4 and the high-affinity IgE receptor 1B (FCER1B) and serum IgE levels in Korean children with asthma. METHODS: We enrolled 238 controls and 742 children with asthma. The CTLA4 +49A/G and FCER1B -654C/T polymorphisms were genotyped by PCR-restriction fragment length polymorphism analysis. RESULTS: We observed no difference in the distribution of CTLA4 +49A/G among controls, children with asthma, and those with atopic asthma. In contrast, the GA genotype of CTLA4 +49A/G in children with atopic asthma was significantly higher compared to that in those with non-atopic asthma. Moreover, significantly higher log Dp/Df-specific IgE levels were found in children with asthma and those with atopic asthma carrying one or two copies of the CTLA4 +49A versus those homozygous for +49G. Gene-gene interactions between CTLA4 and FCER1B with the heterozygote and homozygote of variant genotypes were associated with the log Dp/Df-specific IgE levels, but not asthma development. In addition, children with Dp/Df (+) asthma carried an elevated combined genotype of risk allele compared to those with Dp/Df (-) asthma. CONCLUSIONS: The CTLA4 +49A/G polymorphism may contribute to the production of IgE in Korean children with asthma, especially in Dp/Df-specific IgE levels, but not in the direct development of asthma. In addition, Dp/Df-specific IgE levels with a FCER1B -654C/T polymorphism may involve additive effects.