concanavalin-a and Bronchial-Hyperreactivity

During the baseline period of a clinical trial comparing different dosage schedules of inhaled steroids, asthmatic children (aged 6-10 years) were expected to meet the inclusion criterion of airways hyper-responsiveness (PD(20) methacholine < 80 micro g) after withdrawal of inhaled corticosteroids for 2-8 weeks. However, many children failed to do so.. It has been shown that young wheezing children may outgrow their symptoms. We investigated if differences between children with and without airways hyper-responsiveness after withdrawal of inhaled corticosteroids were compatible with differences between transient and persistent wheezers found in other studies.. Seventy-eight children entered the study, of which 41 developed airways hyper- responsiveness after withdrawal of inhaled corticosteroids, and 37 did not. These two groups of children were compared with respect to differences in demographic, clinical, and immunological features (IL-4, IL-5, IL-10, and IFN-gamma produced by Con A stimulated peripheral mononuclear cells (PBMCs) and serum IL-4, IL-5 and soluble intercellular adhesion molecule-1 (sICAM-1)).. Hyper-responsive children had more atopic features (positive RAST, high IgE, eczema), lower levels of FEV1 and lower concentrations of sICAM-1 than non-hyper-responsive children. Apart from a borderline significantly higher IL-4 production in the hyper-responsive group, other immunologic parameters were comparable. Multivariate logistic regression analysis showed that high serum IgE, low FEV1, and low sICAM-1 levels were independently associated with the presence of airways hyper-responsiveness after stopping inhaled corticosteroids. Atopy was associated with higher concentrations of IL-4 in the hyper-responsive group.. After withdrawal of inhaled corticosteroids many children previously diagnosed with asthma did not develop airways hyper-responsiveness. We conclude that hyper-responsive children share features with persistent wheezers as found in previous studies, whereas the non-hyper- responsive children may represent transient wheezers.

Topics: Animals; Animals, Domestic; Asthma; Birth Weight; Breast Feeding; Breath Tests; Bronchial Hyperreactivity; Bronchoconstrictor Agents; Cell Adhesion Molecules; Child; Concanavalin A; Female; Glucocorticoids; Humans; Hypersensitivity, Immediate; Interferon-gamma; Interleukin-10; Interleukin-4; Interleukin-5; Leukocytes, Mononuclear; Logistic Models; Lymphocyte Activation; Male; Methacholine Chloride; Nitric Oxide; Respiratory Function Tests; Smoking; Unnecessary Procedures