Pollen-induced asthma: a specific pheno-endotype of disease?

Asthma is a heterogeneous syndrome with a significant social and economic impact. While the knowledge of pheno-endotypes has advanced in severe asthma, little attention has been paid to the phenotypes of mild-moderate asthma. Along this line, a systematic review of the current literature on pollen-induced asthma was carried out, targeting the question whether it can be considered a specific phenotype of disease, with a focus on the role of pollen and its interplay with asthma. This article reports the first part of the review, which covered background information on the multiple atmospheric and environmental factors affecting pollen concentration, the molecular bases of pollen-induced allergenicity and the pathogenic effector circuits that sustain and amplify inflammatory signals in response to allergens in sensitized subjects.