ASTHMA, BRONCHIAL HYPERREACTIVITY AND MEDIATOR RELEASE IN CHILDREN WITH BIRCH POLLINOSIS - ECP AND EPX LEVELS ARE NOT RELATED TO BRONCHIAL HYPERREACTIVITY

Background Symptoms of allergic asthma are triggered by allergen expos ure inducing allergic inflammation and hyperreactivity of the bronchi. Objectives To investigate the possible relationship between clinical symptoms and signs of asthma, i.e. branchial variability as measured b y peak expiatory flow rate (PEFR), branchial hyperreactivity (BHR) and mediators of allergic inflammation. Methods Twenty-eight children wit h pollinosis, but no obvious history of asthma, were studied at three occasions, i.e. before, during and after (autumn) the birch pollen sea son. Twelve children sensitive to birch pollen were considered as the case group. Sixteen children, who were only clinically sensitive to gr ass pollen, served as controls. Subjective symptoms of asthma were rec orded by visual analogue scale, BHR was estimated by methacholine bron chial provocation tests, branchial variability PEER and circulating me diators of inflammation, i.e. eosinophil cationic protein, eosinophil protein X, myeloperoxidase and tryptase in serum. Results Bronchial hy perreactivity and by PEFR was more pronounced after than during the se ason (P < 0.01), whereas eosinophil mediators and the peak expiratory flow rate increased during the season (P < 0.05). Except for between P EER variability and BHR in the autumn (r = 0.45; P = 0.014), no correl ations were found. However, in the autumn, the majority of children we re still hyperreactive in the bronchi and showed PEFR variability but the levels of eosinophil mediators in serum had returned to normal lev els. Conclusion Signs and symptoms of asthma did not correlate with se rum levels of mediators of allergic inflammation. Bronchial hyperreact ivity and PEER variability persisted after the pollen season when sign s of bronchial inflammation had disappeared. We hypothesize that eosin ophil mediators and other markers of allergic inflammation disappear a fter the late-phase reaction, whereas BHR persists. This would explain the lack of correlation between the levels of eosinophil mediators in serum and symptoms of asthma and BHR.