Background: Interleukin 4 (IL-4) and its receptor play important roles in the pathologies of asthma and atopy. The alpha subunit of the IL-4 receptor (IL-4RA) is included in 2 types of receptors which have different modulatory effects on immune responses. This distinct pattern reflects involvement in the immunopathology of both asthma and atopy. A number of studies have proven the association between IL4RA gene polymorphisms and asthma and atopy, but it is still an open question whether these variants are functional.
Objectives: To analyze the data from IL4RA gene expression in PBMC in relation to specific polymorphisms - the most frequently studied I50V and Q551R and the less known C-3223T.
Material and methods: The analysis was performed for 36 subjects, both atopic and non-atopic. Real-time polymerase chain reaction (PCR) was used with specific primers for the quantification and genotyping. Delta Ct (ΔCT) and delta-delta Ct (ΔΔCT) values were used for the relative quantification of IL4RA expression in PBMC.
Results: We observed no significant differences in the IL4RA expression profile between the 3 genotypes. A trend toward higher relative expression was observed for homozygous minor I50V and C-3223T genotypes.
Conclusions: We did not find a statistically significant relationship between the genetic polymorphisms and the relative expression of IL4RA. The effect of genetic polymorphism on IL4RA mRNA expression could interfere with other factors, such as environmental stimuli, and should be evaluated in future studies.
Keywords: IL4RA; asthma; atopy; gene expression; polymorphism.