Environmental risk factors and allergic bronchial asthma

Abstract

The prevalence of allergic respiratory diseases such as bronchial asthma has increased in recent years, especially in industrialized countries. A change in the genetic predisposition is an unlikely cause of the increase in allergic diseases because genetic changes in a population require several generations. Consequently, this increase may be explained by changes in environmental factors, including indoor and outdoor air pollution. Over the past two decades, there has been increasing interest in studies of air pollution and its effects on human health. Although the role played by outdoor pollutants in allergic sensitization of the airways has yet to be clarified, a body of evidence suggests that urbanization, with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases observed in most industrialized countries, and there is considerable evidence that asthmatic persons are at increased risk of developing asthma exacerbations with exposure to ozone, nitrogen dioxide, sulphur dioxide and inhalable particulate matter. However, it is not easy to evaluate the impact of air pollution on the timing of asthma exacerbations and on the prevalence of asthma in general. As concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory allergy and bronchial asthma. Pollinosis is frequently used to study the interrelationship between air pollution and respiratory allergy. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc) can affect both components (biological and chemical) of this interaction. By attaching to the surface of pollen grains and of plant-derived particles of paucimicronic size, pollutants could modify not only the morphology of these antigen-carrying agents but also their allergenic potential. In addition, by inducing airway inflammation, which increases airway permeability, pollutants overcome the mucosal barrier and could be able to "prime" allergen-induced responses. There are also observations that a thunderstorm occurring during pollen season can induce severe asthma attacks in pollinosis patients. After rupture by thunderstorm, pollen grains may release part of their cytoplasmic content, including inhalable, allergen-carrying paucimicronic particles.

The Adjuvant Effect of Ambient Particulate Matter Is Closely Reflected by the Particulate Oxidant Potential

“…This includes increased morbidity as a result of allergic disorders such as asthma and allergic rhinitis D'Amato et al 2005;Lippmann 2007). This is evidenced by epidemiologic studies demonstrating an association between the incidence of allergic diseases and the residential freeway proximity as well as an increase in asthma flares after a sudden surge of ambient PM levels Samet et al 2000).…”

Pollution atmosphérique et maladies respiratoires allergiques

“…L'exposition au dioxyde d'azote pourrait favoriser la sensibilisation aux allergènes inhalés. Une exposition à 0,4 ppm de dioxyde d'azote pendant 4 heures augmenterait la réponse immédiate et retardée à l'allergène chez des sujets asthmatiques [27]. pas forcément indépendants, dans la mesure où les mécanismes d'irritation ont un retentissement plus important chez les sujets présentant une maladie respiratoire sous-jacente, qu'elle soit allergique ou non.…”

“…Li et ses collaborateurs [29] [1,2]. D'autres mécanismes concernant le rôle des polluants dans l'induction des allergies respiratoires ne seront pas discutés ici : il s'agit notamment de l'irritation de la muqueuse respiratoire et l'altération de la clairance mucociliaire, qui peuvent faciliter la pénétration des allergènes inhalés dans les voies aériennes et leur présentation aux cellules du système immunitaire [27]. Les polluants atmosphériques pourraient également modifier les propriétés allergéniques des particules transportant les pneumallergènes.…”

Immune System and Environmental Xenobiotics - The Effect of Selected Mineral Fibers and Particles on the Immune Response

“…They include immune-mediated ('allergic') and non immune-mediated ('pseudoallergic') reactions. Particles and mineral fibers are recognized causes of hypersensitivy reactions provoked mostly within respiratory tract and skin (D'Amato et al, 2005;Di Giampaolo et al, 2011). A large number of drugs and an increasing number of environmental agents can result in the appearance of a number of autoantibodies or even autoimmune diseases.…”