Background: Beta 2-Adrenergic receptor polymorphisms occurring at amino acid positions 16 (arginine/glycine) and 27 (glutamine/glutamic acid) are known to be functionally relevant. Associations with several asthma-related phenotypes, such as total serum IgE, have been investigated with different results.
Objective: To determine the contribution of polymorphisms and haplotypes of beta 2-adrenergic receptor with serum IgE levels in children from Argentina with mild, moderate, and severe asthma.
Methods: Beta 2-Adrenergic receptor polymorphisms were analyzed in 124 white asthmatic children using polymerase chain reaction during a 3-year period (January 1, 2005, through December 31, 2007). Total serum IgE level was measured by standard methods in all study participants, and age-adjusted values were determined for each individual.
Results: Serum levels of IgE were 4.3-fold higher than age-adjusted normal values in the study population. No association was found in regard to asthma severity. A significant difference of IgE serum levels was observed among polymorphisms at position 16, with the highest IgE level in the arginine/arginine group (P = .04). At position 27, even though median levels of IgE in homozygous glutamine were 2.2 times higher than homozygous glutamic acid, this increase did not reach statistical significance. When the population was stratified according to the most common homozygous haplotypes (arginine-arginine 16/glutamine-glutamine 27, glycine-glycine 16/glutamine-glutamine 27, and glycine-glycine 16/glutamic acid-glutamic acid 27), no association was found in relation to the serum levels of IgE.
Conclusions: Beta 2-Adrenergic receptor polymorphisms, especially homozygous arginine 16, were associated with higher serum IgE levels in children with asthma. These genetic variants appear to contribute to the IgE level in asthmatic children from Argentina.