Eosinophil cationic protein and eosinophil protein X in the nasal lavage of children during the first 4 weeks of life

Eosinophil cationic protein (ECP) and eosinophil protein X (EPX) are well e stablished as markers of eosinophil activation. We analyzed ECP and EPX con centrations in nasal lavage fluids (NALF) of 378 neonates during their firs t 4 weeks of life. Inclusion criteria were a positive history of parental a llergy and a positive skin prick test or specific IgE (RAST class greater t han or equal to2) against at least one out of a panel of common aeroallerge ns in one or both parents. Twenty-four infants with no history of parental allergy were used as controls. A volume of 2 mi of 0.9% saline was instille d into each nostril and immediately recovered by a suction device. ECP and EPX were analyzed by radioimmunoassay. In 65 samples of three consecutive l avages, EPX was detected in nine samples (13.8%) in the control group, wher eas it was detected in 197/360 samples (54.7%) in the study population. The corresponding figures for ECP were 17/65 (26.2%) in the control group and 173/365 (47.4%) in the study group. Both proteins showed a skewed distribut ion (median/5-95th percentiles for ECP: 0 mug/l [0-69.4] and EPX: 6.6 mug/l [0-73.2]). The differences between the control group and the study group w ere statistically significant, regardless of the allergic disease of the pa rents. Tn children of allergic parents, activation proteins of the eosinoph il granulocyte are released on the nasal mucosal surface in about 50% of th e studied population at the age of 4 weeks. This early onset of eosinophil activation in the nasal respiratory epithelium may reflect a genetic predis position to allergy or early exposure to allergens.