Allelic polymorphisms in the interleukin-4 promoter regions and their association with bronchial asthma among the Russian population.

BACKGROUND

Susceptibility to the development of bronchial asthma (BA) and other atopic diseases is known to be associated with genetic components.

OBJECTIVE

To evaluate the possible role of the polymorphisms in IL-4 gene promoters (C-33T, C-590T and G-1098T) in modulating allergic response and asthma in the Russian population.

METHODS

The polymorphism analysis was carried out by PCR-RFLP; IL-4 and total IgE concentrations were determined by ELISA.

RESULTS

In the case group, the T allele was found at frequencies of 74% (C-33T), 51% (C-590T) and 5% (G-1098T); in the control group the frequencies were 22, 42 and 8%, respectively. Only the C-33T polymorphism was associated with BA. The concentrations of total IgE and serum IL-4 were raised in the case group, while in the control group they were normal. Serum IL-4 level depended on C-33T polymorphism both in the case and control groups, the mutant T allele promoting its increase. The dependence on C-590T polymorphism was detected only in the case group. As for the total IgE level, in both cases it depended on the polymorphism in the case group rather than the control. G-1098T polymorphism did not demonstrate any correlations with total IgE or serum IL-4 levels. All 3 polymorphisms did not affect the severity of BA in the case group. On the basis of the computer analysis, we propose that the T-33C region is the CREB-binding site.

CONCLUSIONS

Our data suggest that IL-4 promoter polymorphism in the Russian population might play a role both conferring susceptibility to BA and modulating the levels of serum IL-4 and total IgE.