Influence of atopy and concomitant sinusitis on serum eosinophil cationic protein levels in asthmatic children

We investigated the influence of atopy as determined by allergen-specific IgE and concomitant sinusitis on serum eosinophil cationic protein (S-ECP) levels in 62 newly diagnosed asthmatic children at exacerbation. Children with atopic asthma had higher S-ECP levels (37.9 ± 5.5 μg/L) as compared to those with nonatopic asthma (8.8 ± 2.1 μg/L, p < 0.01) and controls (6.7 ± 1.1 μg/L, p < 0.01). Neither S-ECP levels nor absolute eosinophil counts (AEC) in peripheral blood correlated with % predicted forced expiratory volume in one second (% FEV₁) in children with atopic asthma. In asthmatic children with atopy, there is no difference of % FEV₁, serum total IgE levels, and AEC between those who also had sinusitis and those who did not. However, S-ECP levels were significantly higher in asthmatic children with concomitant sinusitis, compared to those without, in atopic children (49.5 ± 8.0 μg/L vs. 22.9 ± 5.9 μg/L, p < 0.01), and in nonatopic children alike (15.1 ± 3.0 μg/L vs. 6.7 ± 1.5 μg/L, p = 0.012). Nonatopic children with sinusitis but without asthma had S-ECP levels similar to controls. Thus, S-ECP was confounded by the presence of atopy and sinusitis, and may reflect eosinophilic inflammation of both upper and lower airways.