A regulation-oriented approach for allergenicity categorization of plants

Abstract

Plant species have different degrees of allergenicity. Existing systems categorizing plants according their allergenicity were reviewed to find a method that could serve as the basis for the regulation of green areas. The categorization of plants by their allergenicity serves different purposes: informing allergic patients, warning consumers in horticultural stands, or evaluating urban green areas. The regulation of allergenic plants in trade and their use in urban greening is a new, emerging application of allergenic categorization. Our review showed that the existing systems cannot be used for this purpose, because they cannot fulfill the main requirements of regulation: the methods were often not described, and this affected reproducibility and there was a lack of evidence on allergenicity. To overcome these issues, a new, evidence-based categorization (CARE-S) was developed using genetically determined factors of plants: immunogenicity, morphology, and pollen production. 529 plant taxa were categorized, mostly those common in urban areas in the Pannonian Biogeographical Region. The new system can be applied in other biogeographic areas and on new plant varieties by an online calculator tool. An adaptation strategy of CARE-S in regulations is also proposed. Additional benefits of CARE-S: 1: promoting the development of low-allergenic cultivars, 2: identifying overlooked allergens, recommending their use in clinical tests, 3: calling attention to plant taxa which need more research in allergology or botany; 4: providing a legal tool to prevent the introduction and dispersal of (new) allergenic plants. As a further step the authors suggest developing another tool, epidemiological allergenicity, derivated from CARE-S, aiming to characterize the geographically-determined effects of plants on human populations.