COMPARISON OF BASOPHIL HISTAMINE-RELEASE, EOSINOPHIL CATIONIC PROTEINAND NONSPECIFIC AIRWAY RESPONSIVENESS BETWEEN MITE-SENSITIVE ASTHMATIC AND NONASTHMATIC CHILDREN AND NONALLERGIC CONTROLS

To understand the relevance of allergy to the development of asthma in children, we examined basophil histamine release (HR) with Df antigen , blood eosinophil counts, serum eosinophil cationic protein (ECP) lev els, and bronchial responsiveness to methacholine (PC20) in three grou ps of children, including 36 asthmatics with high. RAST titre for Df ( group 1), 36 non-asthmatics with similarly high RAST titre for Df (gro up 2) and 21 non-asthmatics with negative RAST titre for Df (group 3). The amount of Df antigen inducing 50% HR from basophils did not vary significantly between group 1 and 2 (P>0.05), while none of the cells responded to higher concentrations of Df in group 3. The mean number o f blood eosinophils and level of serum ECP were highest in group 1, an d lowest in group 3, with group 2 being intermediate, and the differen ces were significant between all three groups (P < 0.01). The mean PC2 0 value was the lowest in group 1, intermediate in group 2, and the hi ghest in group 3, and the differences were significant between all thr ee groups (P<0.01). While correlation studies showed that PC20 values of group 2 subjects significantly correlated with their eosinophil num bers (r = -0.48, P < 0.01) and ECP levels (r = -0.49, P < 0.01), such correlations were not found in group 1 subjects. These results suggest that the degree of the eosinophilic inflammation caused by the allerg ic reaction to mites is an important factor in determining the clinica l expression of asthma in atopic subjects.