EOSINOPHILS AND EOSINOPHIL-DERIVED PROTEINS IN CHILDREN WITH MODERATEASTHMA

Laboratory parameters can contribute to the diagnosis of asthma, which is often a difficult procedure in paediatric patients, The aim of thi s study was to investigate the value of eosinophil cationic protein (E CP) and eosinophil-derived neurotoxin (EDN) in the diagnosis of paedia tric asthma. The number of eosinophils, serum ECP and EDN, and urinary EDN were determined in 22 children with stable, allergic asthma, aged 4-14 yrs, and in 17 age-matched healthy controls. Symptoms were monit ored, the peak expiratory now rate (PEFR) was recorded in the younger children, and lung function tests (forced expiratory volume in one sec ond (FEV1) and the provocative concentration of histamine causing a 20 % fall in FEV1 (PC20)) were performed in the older children, None of t he asthmatic children had respiratory symptoms, PEFR was not significa ntly different in asthmatic children compared to controls. The FEV1 % predicted was significantly lower compared to controls. The number of eosinophils, serum ECP and EDN, and urinary EDN were significantly hig her in asthmatic children compared with controls, After correction of serum ECP and EDN, and urinary EDN for the number of eosinophils, the differences between patients and controls disappeared, The nocturnal P EFR and the FEV1 were significantly related to urinary EDN. The result s suggest that serum and urinary concentration of eosinophil-derived p roteins can be determined instead of the number of eosinophils to supp ort the diagnosis of asthma in childhood, The urinary concentration of eosinophil-derived neurotoxin can be especially valuable in young chi ldren, because in this age group quantification of lung function canno t be performed and blood sampling can be difficult.