Influence of b2-adrenergic receptor polymorphisms on asthma exacerbation in children with severe asthma regularly receiving salmeterol

Abstract

Background: New evidence suggests that different β2-adrenergic receptor (β2AR) polymorphisms may influence asthma control in patients receiving long-acting β2-agonists (LABAs) as regular therapy. Objectives: To determine the influence of β2AR polymorphisms on asthma exacerbations in children with severe asthma from Argentina receiving inhaled corticosteroid (ICS) and LABAs regularly. Methods: Ninety-seven children with severe asthma were genotyped for polymorphisms of β2AR at codons 16 and 27. The number of severe exacerbations, the time of first asthma exacerbation, and the number of hospitalizations during 12 months were assessed. Changes on pulmonary function from the beginning to the end of the study were also evaluated. Results: The number of overall asthma exacerbations and the proportion of children with these events were similar among β2AR genotypes at position 16 (Arg/Arg, Arg/Gly, and Gly/Gly) and at position 27 (Gln/Gln, Gln/Glu, and Glu/Glu). The time to first asthma exacerbation was similar among individuals carrying different β2AR polymorphisms. No β2AR genotype association was found in relation to the number of hospitalizations. Longitudinal analysis of forced expiratory volume in 1 second from baseline to the end of the study also showed no differences among β2AR genotypes at position 16 or 27. No association was observed among the 3 most common haplotypes (Arg/Arg-Gln/Gln, Gly/Gly-Gln/Gln, and Gly/Gly-Glu/Glu) and the number of participants with asthmatic crisis or with the overall number of exacerbations. Conclusion: β2AR polymorphisms were not associated with an increased risk of having asthma exacerbations or lung function decline in a population of Argentinian children with severe asthma receiving ICS and LABAs regularly.