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

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.

High-altitude treatment in atopic and nonatopic patients with severe asthma

“…High-altitude treatment has been applied for decades in patients with asthma, especially in children and adolescents with moderate-tosevere atopic disease [6][7][8][9]. The success of this treatment has long been attributed to the absence of house dust mite allergens at altitudes .1,600 m [10].…”

Is the increase in asthma prevalence linked to increase in allergen load?

“…Hospitalizing patients in a house-dustmite-free environment resulted in an improvement in airway responsiveness and a reduction in the medication requirement of a few adults (24). Moreover, removal of house-dust-mite-sensitized children to a low-allergen environment decreased airway hyperresponsiveness and abated asthma (25,26). However, the low-allergen environment must be maintained because these children did not maintain their improvement on returning home.…”

Diversidade da exposição alergênica: implicações na obtenção da eficácia do controle ambiental

“…25 Other similar studies assessed changes of environment in which patients were moved to high altitude places where mite levels were low; in these cases, sensitized patients also improved. [26][27][28] A recent prospective study analyzed environment care measures for children at risk since birth, and demonstrated that there was no difference in sensitization to air allergens between the cared group and controls (in which no environmental measures were undertaken); there was, however, a difference in lung function between groups at age 3 years. 38 Studies that aimed to decrease allergen exposure in households reached conflicting results.…”

“…The enzyme-linked immunosorbent assay (ELISA) was used for detecting the Der p 1, Der f 1, Can f 1 and Fel d 1 allergens as described by Luczynska et al 37 modified by Sopelete et al 28 The following monoclonal antibodies (mAb) for capture were used: anti-Der p 1 (clone 5H8), anti-Der f 1 (clone 6A8), anti-Fel d 1 (clone 6F9), and anti-Can f 1 (clone 6E9); the concentration was 10 mg/ml in a carbonate-bicarbonate buffer at 0.06M and pH 9.6. Detection was done using biotinilated mAb, as follows: anti-Der p 1 and anti-Der f 1 (4C1), anti-Fel d 1 (3F4C4) and polyclonal rabbit serum anti-Can f 1 at 1:500.…”

“…Various published papers had shown that there are variable responses to allergen control measures; the study design and the response assessments, however, varied among these papers, which has generated controversies among physicians. [17][18][19][20][21][22][23][24][25][26][27][28] The purpose of this paper was to discuss the difficulty of controlling allergen exposure and to review various studies in different environments within which individuals spend their days.…”