Association of FCER2 polymorphism with IgE levels and exacerbations in asthmatic children

New evidence suggests that polymorphisms in the low-affinity IgE receptor ( FCER2 ) were associated with IgE levels and with increased risk of asthma exacerbation in children taking inhaled corticosteroids (ICS). Objectives: To evaluate the association of FCER2 variant (T2206C) with IgE levels in asthmatic children and, to determine the influence of this variant on exacerbations in patients with severe asthma taking ICS and LABAs. Methods: Children with mild, moderate and severe asthma (n 222) were genotyped for T2206C variant by PCR-RFLP. IgE levels were measured by ELISA and aged-adjusted values were determined for each individual. The number of severe exacerbations, the time of first exacerbation, number of hospitalizations and pulmonary function over 12 months were assessed in the severe group (n 99). Results: The C allele frequency was significantly lower than the observed in other Caucasian populations (0.17, p<0.0001) 1 . A significant difference of IgE levels was observed among FCER2 variants with the highest value in the CC group (12.4 times over normal values) compared with TT (9) and TC (10.3) groups (p<0.05). The number and severity of asthma exacerbations, the time to first exacerbation and hospitalizations were similar among different FCER2 variants. The analysis of FEV1 from baseline to the end of the study showed no differences among FCER2 genotypes. Conclusions: CC genotype was significantly less frequent in Argentinean population and was associated with higher IgE levels. FCER2 variants not related to increased risk of having asthma exacerbations or lung function decline in severe asthmatic children taking ICS and LABAs regularly. (1) Koster E. et al. Allergy 2011;66:1546–1552.