Saliva and Serum Eosinophil Cationic Protein in Asthmatic Children and Adolescents with and without Allergic Sensitization

Abstract

Saliva eosinophil cationic protein (ECP) is higher in asthmatic adults than in healthy ones. However, its relationship with asthma severity, other atopic conditions and allergic sensitization have not been reported. Saliva collection is painless, readily acceptable to children and parents, and can be a potentially useful body fluid to measure asthma biomarkers. We recruited 102 physician-diagnosed young asthmatic subjects from outpatient clinics with change in FEV1≥12% with inhaled salbutamol and collected data on asthma severity, concurrent allergic rhinitis (AR) and atopic dermatitis (AD), and medication used (bronchodilator and corticosteroid). We measured whole saliva and serum ECP and performed skin prick tests (SPT) for three dust mites (Dermatophagoides pteronyssisinus, Dermatophagoides farinae and Blomia tropicalis) and two cockroaches (Periplaneta americana and Blatella germanica). Median salivary ECP was 84.6 μg/l (inter-quartile range [IQR]: 40.9–147.9) and median serum ECP was 14.7 μg/l (IQR: 6.4–32.1). Serum ECP was only higher in children whose sleep was disturbed by asthma in the past year than those who were not (geometric mean [GM]: 18.9 vs. 11.1 μg/l, relative mean difference [RMD]: 1.71 [95%CI: 1.09–2.69]). Serum ECP was increased among asthmatic children on inhaled corticosteroid than those not using them (GM: 15.6 vs. 8.1 μg/l, RMD: 1.93 [95%CI: 1.11–3.39]). Salivary ECP was not associated with asthma severity, concurrence of atopic conditions, medications used, or any SPT parameter. Saliva ECP did not correlate with serum ECP (rs = 0.032, p = 0.790). Salivary and serum ECP did not correlate with wheal size for any skin prick test.