ABSTRACT
Pollen originating from weeds is one of the most important sources of allergenic proteins. The term weed is not a botanical classification but is used to describe a highly heterogeneous group of plants lacking appreciable economic or esthetic value. Presently, 47 weed pollen allergens are listed in the official International Union of Immunological Societies (IUIS) allergen nomenclature database with Ambrosia (ragweed), Artemisia (mugwort), Parietaria (pellitory), Chenopodium (chenopod), Salsola (Russian thistle), Plantago (plantain), and Mercurialis (annual mercury) representing the most clinically relevant species. The major allergens thereof belong to the family of pectate lyases, defensin-like, Ole e 1–like, and nonspecific lipid transfer proteins. Profilins and polcalcins are cross-reactive weed pollen pan-allergens. Pollen food syndromes with association to weed pollen allergy were mainly described for allergens found in the Asteraceae family.
Skin prick testing with allergen extracts allows clinicians to identify sensitivity to given pollen. However, extract-based allergy diagnosis of weed pollen is often difficult due to multisensitization of patients, overlapping flowering seasons, and similar allergen profiles. Besides skin prick testing, a molecule-based allergy diagnostic test for clinical use in a single or multiplex format quantifying the IgE binding to several weed pollen allergens is available. Clinical trials with allergenic extracts utilized both subcutaneous and sublingual immunotherapy application routes. Novel allergen derivatives based on ragweed Amb a 1, mugwort Art v 1, and pellitory Par j 1 and Par j 2 are being developed for safer and more effective forms of specific immunotherapy.
