Effective allergen avoidance at high altitude reduces allergen-induced bronchial hyperresponsiveness

Am J Respir Crit Care Med. 1994 Jun;149(6):1442-6. doi: 10.1164/ajrccm.149.6.8004296.

Abstract

We studied the effects of reduced allergen exposure on bronchial hypereactivity (BHR) in two groups of asthmatic children allergic to house dust mites (HDM) living at high altitude for 9 continuous mo. In the first group the serum levels of total and HDM-specific IgE showed significant decreases after 3 mo (p < 0.001 and p < 0.02, respectively) and after 9 mo (p < 0.001). Three months after returning home the total IgE levels had increased significantly (p < 0.001). The mean percentage fall in peak expiratory flow after exercise testing improved after 3 and 9 mo (p < 0.05), but it had deteriorated after 3 mo at home (p < 0.01). The methacholine PD20-FEV1 increased after 3 mo (p = 0.001) and further after 9 mo (p < 0.001), with a decrease after the 3-mo period at sea level (p = 0.01). In the second cohort there was a significant increase in HDM PD20-FEV1 after 6 and 9 mo (p < 0.001), with a slight decrease of magnitude of the allergen-induced late reaction. Histamine PD20-FEV1 significantly increased after 6 and 9 mo at high altitude, particularly in the challenges performed after the HDM bronchial provocation (p < 0.01). Our data demonstrate that allergen avoidance in asthmatic children not only decreases nonspecific BHR but also decreases allergen sensitivity, late allergen-induced bronchial reactions, and enhancement of BHR by allergen challenge.

MeSH terms

  • Allergens* / immunology
  • Altitude*
  • Analysis of Variance
  • Animals
  • Asthma / physiopathology*
  • Bronchial Hyperreactivity / diagnosis
  • Bronchial Hyperreactivity / epidemiology
  • Bronchial Hyperreactivity / etiology*
  • Bronchial Hyperreactivity / prevention & control*
  • Bronchial Provocation Tests
  • Child
  • Cohort Studies
  • Dust*
  • Environmental Monitoring
  • Epidemiological Monitoring
  • Exercise Test
  • Forced Expiratory Volume
  • Histamine
  • Humans
  • Hypersensitivity / blood
  • Hypersensitivity / complications*
  • Hypersensitivity / diagnosis
  • Hypersensitivity / immunology
  • Hypersensitivity / prevention & control*
  • Immunoglobulin E* / blood
  • Immunoglobulin E* / immunology
  • Methacholine Chloride
  • Mites*
  • Peak Expiratory Flow Rate
  • Primary Prevention
  • Recurrence
  • Residence Characteristics
  • Residential Facilities
  • Seasons
  • Skin Tests
  • Time Factors

Substances

  • Allergens
  • Dust
  • Methacholine Chloride
  • Immunoglobulin E
  • Histamine