FACTORS CONTRIBUTING TO THE OCCURRENCE AND PREDICTABILITY OF BRONCHIAL HYPERRESPONSIVENESS TO METHACHOLINE IN CHILDREN

Using a stepwise logistic regression analysis, we investigated clinica l data, allergologic findings, spirometric data, and the cellular and humoral immune system in order to gain new insights into the role thes e parameters play in bronchial hyperresponsiveness to methacholine in children and to create a model for the prediction thereof. Bronchial h yperresponsiveness, which was found in 124 of 462 children (26.8%), wa s observed to have been influenced by an increased level of eosinophil s, the positivity of the skin prick test for any of the allergens test ed a decreased baseline forced expiratory volume in 1 second (FEI(1)) (percent predicted), a decreased maximum expiratory flow at 50% expira tion as a percent of forced vital capacity, and a decreased level of k appa-chain-assembled immunoglobulins. Logit analysis disclosed that th e influence of all other parameters on the occurrence of bronchial hyp erresponsiveness was of no further statistical significance. The degre e of bronchial hyperresponsiveness (provocative dose causing a 20% fal l in FEV(1)) showed a statistically significant correlation with the e osinophil count (Spearman's r = -0.198) and FEI(1) (percent predicted) (Speaman's r = 0.203). Our findings suggest that allergic sensitizati on and eosinophilic reaction in children are major factors in contribu ting to the occurrence of bronchial hyperresponsiveness to methacholin e.