Martín-Muñoz F, Moreno-Ancillo A, Pestaña J A, Contreras-Porta J, Díaz-Peña J M, Ojeda J A
Childhood Allergy Service, La Paz Children's Hospital, Madrid, Spain.
J Investig Allergol Clin Immunol. 1997 Jul-Aug;7(4):229-33.
Nonspecific bronchial hyperresponsiveness and atopy are considered risk factors in the development of asthma. Bronchial responsiveness to allergens could be the most important factor in extrinsic asthma. The trial was designed to investigate the role of specific and nonspecific bronchial responsiveness and atopy in a pure model of extrinsic asthma in children. One hundred and thirty-seven patients with pollen allergy were evaluated. Twenty children with allergy to grass pollen (Lolium perenne) alone, with symptoms only in the grass pollen season, were selected. Their score of symptoms, airway responsiveness to methacholine in and out of season, airway responsiveness to Lolium perenne out of season, and total and specific IgE were assessed. Twelve were male and eight female. Mild asthma was observed in 14, and moderate asthma in six. Age of onset of symptoms ranged from three to 13 years of age. Significant seasonal increase in airway responsiveness to methacholine was found (p = 0.002). Specific bronchial challenge test was positive in all patients. Lolium pernne PD20 ranged from 2.3 to 155.5 inhalation units. An inverse association between age of onset of symptoms and severity of asthma was shown (p = 0.001). Increase in nonspecific bronchial responsiveness was related to the appearance of symptoms during the spring, but it showed no relationship to the severity of symptoms. Severity of asthma during the spring correlated with the intensity of allergen airway responsiveness (p = 0.02). Levels of total and specific IgE were not related to the degree of specific or nonspecific airway responsiveness. Severity of extrinsic childhood asthma is determined by bronchial response to allergens. Bronchial hyperresponsiveness to methacholine during the spring can be the consequence of environmental exposure to allergens. The intensity of airway responsiveness to methacholine has no predictive value in the severity of pure extrinsic childhood asthma.
非特异性支气管高反应性和特应性被认为是哮喘发病的危险因素。支气管对过敏原的反应性可能是外源性哮喘中最重要的因素。该试验旨在研究特异性和非特异性支气管反应性以及特应性在儿童单纯外源性哮喘模型中的作用。对137例花粉过敏患者进行了评估。选择了20例仅对黑麦草花粉（多年生黑麦草）过敏且仅在黑麦草花粉季节出现症状的儿童。评估了他们的症状评分、季节内外对乙酰甲胆碱的气道反应性、季节外对多年生黑麦草的气道反应性以及总IgE和特异性IgE。其中12例为男性，8例为女性。观察到14例为轻度哮喘，6例为中度哮喘。症状出现的年龄范围为3至13岁。发现对乙酰甲胆碱的气道反应性有显著的季节性增加（p = 0.002）。所有患者的特异性支气管激发试验均为阳性。多年生黑麦草的PD20范围为2.3至155.5吸入单位。症状出现的年龄与哮喘严重程度之间呈负相关（p = 0.001）。非特异性支气管反应性的增加与春季症状的出现有关，但与症状的严重程度无关。春季哮喘的严重程度与过敏原气道反应性的强度相关（p = 0.02）。总IgE和特异性IgE水平与特异性或非特异性气道反应性的程度无关。儿童外源性哮喘的严重程度由支气管对过敏原的反应决定。春季对乙酰甲胆碱的支气管高反应性可能是环境暴露于过敏原的结果。对乙酰甲胆碱的气道反应性强度对单纯儿童外源性哮喘的严重程度没有预测价值。
