Variation of the group 5 grass pollen allergen content of airborne pollen in relation to geographic location and time in season

The grass pollen season 2014 in Vienna: A pilot study combining phenology, aerobiology and symptom data

“…Although group 1 and group 5 allergens are considered as major allergens within the Poaceae family, show high cross-reactivity rates within their allergenic groups and explain pollen sensitization (Andersson and Lidholm, 2003), patients can also be sensitized to minor allergens (Schmid-Grendelmeier, 2010). There are also differences in allergen content of the ambient air (Phl p 5), grass pollen concentrations and symptom loads on a European scale (Bastl et al, 2016;Buters et al, 2015). Moreover, recent studies highlight the unique biochemical profiles for each different grass species (Bullimore et al, 2012) and varying amounts of major allergen content (Moingeon et al, 2008).…”

Defining pollen exposure times for clinical trials of allergen immunotherapy for pollen‐induced rhinoconjunctivitis – an EAACI position paper

“…Finally, one has to bear in mind that the average measurement error with a Hirst-type trap amounts to 25% (variability increasing with lower pollen concentrations) (16,33,48). Thresholds of allergen exposure triggering an allergic reaction are typically in a relatively low range of the measured concentrations (between 0 and 100 pollen/m 3 ).…”

“…Under specific meteorological conditions, for example, high humidity, allergens can bind to particles smaller than pollen and under certain conditions be released from pollen (16,56). In addition, the question of the variability of airborne concentrations of the major allergens, for example Bet v 1 (57), Ole e 1 (17) or Phl p 5 (16), is not yet fully understood and there is no data concerning concentrations of the minor allergens of birch, olive or grass pollen.…”

“…If this novel analysis creates better discrimination of the effects of AIT compared with placebo, it may be suitable as an additional secondary/exploratory endpoint that takes into account some of the limits of pollen data: that is, reproducibility, distance to trap, dead zones, different trap performances, and differences between pollen concentrations and major allergen release (16). However, it should be clearly emphasized that at present such a post hoc analysis is not accepted by regulatory bodies such as the EMA and this approach cannot replace the whole season and peak season based on the analysis of pollen/m 3 (4).…”

“…In the absence of standardized definitions direct comparisons between different RCTs on the efficacy of AIT with pollen extracts and meta-analysis of such trials must be suboptimal due to inevitable heterogeneity. In addition, allergen exposure is reported as pollen/m 3 , and recent literature suggests a likely discrepancy between pollen/m 3 and the actual magnitude of release of allergenic proteins from the pollen (15)(16)(17). The EAACI Immunotherapy and the EAACI Aerobiology and Pollution Interest Groups have conducted a Task Force (TF) on 'Definition of clinical-relevant thresholds of allergenexposure for analysis of outcomes in AIT'.…”