To what extent is allergen exposure a risk factor for the development of allergic disease?

Abstract

The role of allergen exposure in the development of allergic disease has been a matter of considerable debate, and our understanding of the importance of allergens has evolved over the last 25 years. Several observational and primary prevention studies have investigated these relationships, and different studies reported inconsistent, and sometimes opposite findings. It has to be emphasized that a clear understanding of how aeroallergen exposure occurs, and accurate and reproducible measurement of exposure are essential prerequisites for understanding the role of exposure. However, our current understanding of how we get exposed to allergens is not based on solid evidence, but on a number of assumptions, and we urgently need to develop better proxy measures (or indices) of exposure. In addition, the relative importance of the timing of exposure (e.g. early compared to exposure in later life) is unknown. It is also unclear which route of exposure is the most relevant (e.g. inhaled vs. oral vs. transcutaneous). Available data suggest that the dose-response relationship between allergen exposure and allergic disease may differ between different allergens, dose ranges and exposure patterns, and these relationships may further differ between different populations and geographical areas. It is increasingly clear that childhood asthma and atopy are not single phenotypes, and it is likely that allergen exposure has different effect on distinct subgroups under the umbrella terms of 'sensitization' and 'asthma'. Susceptibility to allergen exposure, other environmental exposures and their interactions may also differ between individuals with different genetic predispositions. However, the precise nature of these complex relationships is unclear. We need a holistic approach offered by systems biology, with integration of information on the standardized and reliable measures of exposures (including allergens and other relevant exposures) with genetic and biological data to fully understand the role of allergens in the development of allergic disease.

Clinical observation of the adverse drug reactions caused by non-ionic iodinated contrast media: results from 109,255 cases who underwent enhanced CT examination in Chongqing, China

“…In addition, contact or inhalation of the allergens, including pollen in the air by people with a predisposition to allergies could also be associated with the phenomenon. 18,19 Some other phenomenon were also found in the present study. Although the phenomenon were not very common, we should also pay attention to it.…”

Asthma phenotypes and IgE responses

“…This difference is attributed to the aerodynamic properties of the carrier particles, which are highest for HDM (>10 µm) and confined in a dust reservoir in the absence of disturbance, and are largely airborne for pets allergens (<5 µm). These aerodynamic properties clearly affect the exposure of an individual, with exposure doses being much lower for HDM and thought to be unable to induce tolerance [41]. At the present time, no consensus has been reached regarding the age, dose and mechanism by which allergen exposure will induce sensitisation alone and/or associated clinical outcomes.…”

Approaches to assess IgE mediated allergy risks (sensitization and cross-reactivity) from new or modified dietary proteins

“…In theory, this exposure results in induction of tolerance, although if exposure is not high and/or frequent enough, or does not occur within an appropriate time-window it will lead to sensitization in predisposed individuals (Du Toit et al, 2015). Indeed, experience from animal models as well as some epidemiological evidence of non-food allergens shows that the dose-response for food allergens may not be linear (Custovic, 2015). Increasing the dose of allergenic protein does not necessarily increase the induction of IgE (Kroghsbo et al, 2014a).…”