Birch pollen allergy in Europe

Abstract

Birch and other related trees of the families Betulaceae and Fagaceae (alder, hazel, oak, hornbeam, chestnut, and beech) constitute the birch homologous group. This grouping is primarily based on the extensive IgE cross-reactivity of allergen homologs to the major birch allergen Bet v 1. Birch pollen is the most dominant tree pollen in Northern and Central Europe and is a major cause of allergic rhinitis and, possibly, asthma symptoms. Over the last few decades, levels of birch pollen have risen and the period of exposure has increased due to climate changes. Subsequently, the prevalence of birch pollen sensitization has also increased. The cross-reactivity and sequential pollen seasons within the birch homologous group create a prolonged symptomatic allergy period beyond birch pollen alone. Furthermore, many plant food allergens contain homologs to Bet v 1, meaning that the majority of patients with birch pollen allergy suffer from secondary pollen food syndrome (PFS). As a result, the negative impact on health-related quality of life (HRQoL) in patients allergic to birch pollen is significant. The purpose of this manuscript was to narratively review topics of interest such as taxonomy, cross-reactivity, prevalence, clinical relevance, PFS, and HRQoL with regard to birch pollen allergy from a European perspective.

Dynamics Rationalize Proteolytic Susceptibility of the Major Birch Pollen Allergen Bet v 1

“…As described above, Bet v 1 is among the most extensively studied allergen proteins in experiment, computational models and clinical studies (Spangfort et al, 2003;Bollen et al, 2010;Berkner et al, 2014;Garrido-Arandia et al, 2014;Grutsch et al, 2014;Kitzmuller et al, 2015;Kamenik et al, 2016;Moingeon et al, 2016;Biedermann et al, 2019). With an estimated 100 million of individuals suffering from birch pollen allergy, it is also one of the clinically most relevant allergens (Hartl et al, 2004).…”

Recent developments and highlights in allergic rhinitis

“…Several studies showed that the incidence or severity of AR is closely correlated with levels of pollen allergens in ambient air in multiple countries and regions . A recent review reported that the prevalence of birch pollen sensitization increased owing to rising levels of birch pollen concentration and chance of exposure in Europe . Data from the BAMSE cohort demonstrate that exposure to molds or dampness during infancy increases the risk of asthma and rhinitis up to 16 years of age, particularly for rhinitis and persistent asthma through adolescence .…”

“…Climate change contributes to increases in chemical air pollutant and aeroallergen production and their distribution . Climate change affects vegetation, resulting in changes in the start, duration, intensity, and distribution of allergenic pollen . Biedermann et al have shown that climate change has increased the levels of birch pollen and period of exposure, with a higher prevalence of birch pollen sensitization.…”

“…34,35 A recent review reported that the prevalence of birch pollen sensitization increased owing to rising levels of birch pollen concentration and chance of exposure in Europe. 36 Data from the BAMSE cohort demonstrate that exposure to molds or dampness during infancy increases the risk of asthma and rhinitis up to 16 years of age, particularly for rhinitis and persistent asthma through adolescence. 37 Tischer et al 38 provide evidence using meta-analysis that molds or dampness exposure in early life is associated with increased risk of developing asthma in young children and AR symptoms in school-age children in eight European birth cohorts.…”

“…33,36,41,42 Climate change affects vegetation, resulting in changes in the start, duration, intensity, and distribution of allergenic pollen. 33,36,41,43,44 Biedermann et al 36 have shown that climate change has increased the levels of birch pollen and period of exposure, with a higher prevalence of birch pollen sensitization. The extremely high prevalence of pollen-induced AR in the grasslands of Northern China is associated with high seasonal pollen exposure influenced by local environmental and climate conditions.…”