New data analysis in a population study raises the hypothesis that particle size contributes to the pro-asthmatic potential of small pet animal allergens

Abstract

BackgroundThe size of inhaled particles influences where they deposit and theoretically should be important for the development of airway inflammation and responsiveness. Our aim was to assess if sensitization to smaller-sized aeroallergens relates to higher prevalence of treated asthma, increased airway responsiveness, and airway and systemic inflammation.MethodsMolecular-based IgE antibody determination was done in 467 subjects. Sensitized subjects were grouped based on the particle size of the aeroallergen: (1) Large particles only (mainly pollen); (2) Medium-sized particles (sensitized to mainly mite and mold and possibly to large particles); and 3) Small particles (sensitized to pet allergens and possibly to medium- and/or large-sized particles). Airway responsiveness to methacholine, exhaled nitric oxide (FENO), and serum eosinophil cationic protein (S-ECP) were measured. Asthma and rhinitis were questionnaire-assessed.ResultsSubjects sensitized to small particles had higher prevalence of treated asthma (35% versus 10%, P < 0.001), higher FENO50 (32 versus 17 ppb, P < 0.001), higher S-ECP (10 versus 7.5 ng/mL, P = 0.04), and increased bronchial responsiveness (dose-response slope, 5.6 versus 7.5, P < 0.001) compared with non-atopics. This was consistent after adjusting for potential confounders. Sensitization to only large or to medium and possibly also large aeroallergen particles was not related to any of these outcomes after adjustments.ConclusionsSensitization to smaller particles was associated with a higher prevalence of asthma under treatment, higher airway responsiveness, and airway and systemic inflammation. Mapping of IgE sensitization to small particles might help to detect subjects having increased airway and systemic inflammation and bronchial responsiveness, indicating increased risk of developing asthma.

IgE sensitization to food allergens and airborne allergens in relation to biomarkers of type 2 inflammation in asthma

“…In the present study, S‐ECP levels were higher in asthmatics sensitized to food allergens, but this increase was not consistent after adjustments for potential confounders. In a previous study, adults sensitized only to food allergens did not differ in S‐ECP levels compared with non‐allergic asthmatics. According to Koh et al., serum S‐ECP correlates directly with activated eosinophils in bronchial mucosa in adult asthmatics and is a more sensitive marker of asthma severity than peripheral blood eosinophil counts in acute exacerbations in children .…”

“…We have previously reported that having IgE antibodies against perennial airborne allergens was the type of IgE sensitization that had the strongest relation to asthma and FeNO . S‐ECP is also related to sensitization to cat and dog allergens . Sensitization to perennial allergens is associated with higher urinary eosinophil‐derived neurotoxin (U‐EDN) levels than sensitization to seasonal allergens .…”

Increased sensitization to several allergens over a 12‐year period in Brazilian children

“…Therefore, even people without pets at home may often be sensitized to their allergens. 9 Another robust result was the increase in sensitization to grass, both among allergic individuals and in the control group. Pollens appear as of great importance in the etiology of allergies.…”

“…the so-called "indoor lifestyle". 1,9 Based on this concept, an important growth in allergic diseases rates, especially respiratory allergies, is being reported in different studies. 5,9 Developing countries, such as Brazil, could experience these changes with a delay of a few years, which would explain the increase in the sensitization within the evaluated children.…”

Multiplex component‐based allergen microarray in recent clinical studies

“…In the same study, asthma sensitization against perennial allergens had the strongest association with asthma, FeNO levels and bronchial responsiveness, while sensitization against food allergens was independently related to FeNO. Among perennial allergens, sensitization to cat and/or dog components was more related to systemic and local eosinophilic inflammation, bronchial responsiveness and asthma needing to be treated [48]. Furthermore, cosensitization to food allergens strengthened the association with asthma prevalence and airway inflammation in pollen-sensitized individuals.…”