Allergen‐induced early and late asthmatic responses to inhaled seasonal and perennial allergens

Abstract

Different mechanisms may be involved in modulating the magnitude of the LAR, according to the type of allergen. HDM seems to induce a stronger LAR than pollens, animal allergens being intermediary in this regard.

Sputum cytology during late‐phase responses to inhalation challenge with different allergens

“…Unexpectedly, we found no association between the number of eosinophils and neutrophils that infiltrate into the airways after allergen challenge and the severity of the LAR. On the other hand, individuals with increased eosinophil and neutrophil sputum counts at baseline had a more severe LAR, consistent with results from Boulet et al These results suggest that the presence of larger numbers of granulocytes at baseline, perhaps reflecting ongoing or chronic inflammatory processes, is a risk factor for a more severe asthma exacerbation upon acute allergen exposure.…”

“…The magnitude of the LAR reflects the severity of airway inflammation induced by allergen exposure and can vary considerably between individuals. Importantly, Boulet et al found that some of this variation in the magnitude of the LAR can be explained by the allergen type used in the challenge . On the other hand, the allergen used in the inhalation challenge did not determine the absolute number of eosinophils or neutrophils measured in sputum, but these cell types were analyzed individually and sputum inflammatory subtypes were not considered.…”

Inhalation of diesel exhaust and allergen alters human bronchial epithelium DNA methylation

“…This also applies to the fact we included subjects reactive to different allergens, primarily to increase our overall sample size. Furthermore, a recent examination of allergen effect on human airways showed no such effect modification on outcomes related to ours (sputum inflammatory cells or methacholine responsiveness) 41 . Furthermore, we recognize that the changes in DNA methylation after 4 weeks could be partially reflective of inflammation related to the stress of the prior bronchoscopy (independent of the exposures), but this concern is attenuated by the expectation that bronchoscopy-related inflammation would have resolved within the 4-week interval.…”

The effect of allergen‐induced bronchoconstriction on concentration of 5‐oxo‐ETE in exhaled breath condensate of house dust mite‐allergic patients

“…Allergic asthma patients respond to a specific allergen provocation with immediate bronchoconstriction, named early asthmatic reaction (EAR). In some of them, a late asthmatic reaction (LAR) develops after 3‐8 hours causing a prolonged narrowing of the airways . The presence of a LAR is associated with infiltration of the bronchial wall by inflammatory cells .…”