Aeroallergen botany

The Clinical Relevance of Pollen Versus Fungal Spores in Allergic Diseases

Pollen and fungal spores are associated with seasonal and perennial allergies. However, most scientific literature thus far suggests that pollen allergy is more clinically relevant than fungal allergy. Several environmental and biological factors and the difficulty in producing reliable fungal extracts account for this. Biodiversity, taxonomy, and meteorology are responsible for the types and levels of pollen and fungal spores, their fragments, and the presence of free airborne allergens. Therefore, it is difficult to accurately measure both pollen and fungal allergen exposure. In addition, understanding the enzymatic nature of fungal and some pollen allergens, the presence of allergenic and nonallergenic substances that may modulate the allergic immune response, and allergen cross-reactivity are all necessary to appropriately evaluate both sensitivity and exposure. The raw materials and manufacturing processes used to prepare pollen versus fungal extracts differ, further increasing the complexity to properly determine allergic sensitivity and degrees of exposure. The pollen extracts used for diagnosis and treatment are relatively consistent, and some have been standardized. However, obtaining clinically relevant fungal extracts is more difficult. Doing so will allow for the proper selection of such extracts to more appropriately diagnose and treat both pollen- and fungal-induced allergic diseases.

Allergy to oak pollen in North America

Background: Oak pollen is an important allergen in North America. The genus Quercus (oak) belongs to the family Fagaceae under the order Fagales. Objective: The objective of this article was to narratively review the oak pollen season, clinical and epidemiologic aspects of allergy to oak pollen, oak taxonomy, and oak allergen cross-reactivity, with a focus on the North American perspective. Methods: A PubMed literature review (no limits) was conducted. Publications related to oak pollen, oak-related allergic rhinitis with or without conjunctivitis, and oak-related allergic asthma were selected for review. Results: Oak species are common throughout the United States and contribute up to 50% to overall atmospheric pollen loads. Mean peak oak pollen counts can reach >2000 grains/m³. The start of the oak pollen season generally corresponds to the seasonal shift from winter to spring based on latitude and elevation, and may begin as early as mid February. The duration of the season can last > 100 days and, in general, is longer at lower latitudes. In the United States, ∼30% of individuals with allergy are sensitized to oak. The oak pollen season correlates with increased allergic rhinitis symptom-relieving medication use and asthma-related emergency department visits or hospitalizations. Oak falls within the birch homologous group. Extensive immunologic cross-reactivity has been demonstrated between oak pollen and birch pollen allergens, and, more specifically, their major allergens Que a 1 and Bet v 1. The cross-reactivity between oak and birch has implications for allergy immunotherapy (AIT) because guidelines suggest selecting one representative allergen within a homologous group for AIT, a principle that would apply to oak. Conclusion: Allergy to oak pollen is common in North America and has a substantial clinical impact. Oak pollen allergens are cross-reactive with birch pollen allergens, which may have implications for AIT.

Impact of Tree Pollen Distribution on Allergic Diseases in Serbia: Evidence of Implementation of Allergen Immunotherapy to Betula verrucosa

Background and objectives: The relationship between air pollen quantity and the sensitization of allergic patients is crucial for both the diagnosis and treatment of allergic diseases. Weather conditions influence the distribution of allergenic pollen and increases in pollen concentration may negatively affect the health of allergic patients. The aim of this study was to analyze the implementation of allergen immunotherapy with regard to air pollen concentration. Material and Methods: Here we examined the relationship between Betula air pollen concentration and the usage of Betula verrucosa allergen immunotherapy in Serbia. Examination covered the period from 2015 to 2018. Measurement of airborne pollen concentration was performed with Lanzoni volumetric pollen traps. The evidence of the usage of sublingual allergen immunotherapy (SLIT) was gathered from patients with documented sensitization to specific pollen. Results: During this period tree pollens were represented with 58% ± 21% of all measured air pollen species, while Betula pollen represented 15% ± 8% of all tree pollens. Betula pollination peaked in April. Allergen immunotherapy to Betula verrucosa in Serbia is entirely conducted as sublingual immunotherapy and represents 47.1% ± 1.4% of issued tree pollen SLIT. The use of pollen SLIT increased by 68% from 2015 to 2018, with an even greater increase in usage recorded for Betula SLIT—80%. Conclusions: This analysis shows a clear causative relationship between pollination and the type/prevalence of applied allergen immunotherapy. Information about the flowering seasons of allergenic plants is very important for people who suffer from allergy, for clinical allergologists, as well as for governing authorities. The presented data is of practical importance to the proper timing of immunotherapy initiation and of importance for urban landscaping. The obtained data can be the starting point for the instatement of a thorough epidemiological study and the inclusion of Serbia on the pollen map of Europe.

Pollen used to produce allergen extracts

OBJECTIVE

To review the use of pollen for the production of allergen extracts to diagnose and treat allergic diseases, examine the associated regulations, and highlight candidate areas for improvement.

DATA SOURCES

A PubMed search was performed using focused keywords combined with a review of regulatory documents and industry guidelines.

STUDY SELECTIONS

The information obtained through literature, documents, and industry was scrutinized and used with personal experience and expertise to write this article.

RESULTS

Both genetic and environmental factors affect the allergenic composition of pollen because it is a biologically active pharmaceutical ingredient obtained from nature. The potential effect of airborne contaminants in pollen requires major attention but can be properly addressed through careful collection practices, combined with a proper interpretation of the data on purity obtained for each pollen lot. The regulations associated with pollen used to manufacture allergen extracts in the United States and Europe and the numbers of pollen allergen extracts commercially available in both areas of the world differ. A critical parameter to select the appropriate extracts for diagnosis and allergen immunotherapy is to understand the phenomenon of cross-reactivity among pollen families, genera, and species.

CONCLUSION

Physicians should be aware of the factors responsible for the qualitative and quantitative composition of pollen allergen extracts and the associated regulations to produce suitable extracts to diagnose and treat allergic diseases. Collaboration and cooperation among allergen manufacturing companies and regulatory agencies are necessary.