Marker allergens of weed pollen – basic considerations and diagnostic benefits in the clinical routine

Abstract

The term weed is referring to plants used as culinary herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pollen of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen allergies. Presently, 35 weed pollen allergens have been identified. The most relevant belong to the protein families of pectate lyases, defensin-like proteins, non-specific lipid transfer proteins, and Ole e 1-like proteins. The sensitization frequency depends on geographic regions and might affect more than 50 % of pollen allergic patients in distinct regions. Due to overlapping flowering seasons, similar habitats, polysensitizations and cross-reactive (pan)-allergens, it is difficult to diagnose genuine weed pollen sensitization using pollen extracts. Marker allergens for component-resolved diagnostics are available for the important weed pollen. These are Amb a 1 (ragweed), Art v 1 (mugwort), Pla l 1 (English plantain) and Par j 2 (pellitory). Molecule-based approaches can be used to identify the primary sensitizer and thus enable selection of the appropriate weed pollen extracts for allergen immunotherapy.

EAACI Molecular Allergology User's Guide

“…The term weed does not constitute a botanical family, but rather refers to diverse plants used as culinary herbs, medicinal plants that are ecologically adaptive and invasive segetal plants. Pollen of weeds mediating IgE‐related allergic reactions are found in monocot (Poaceae) and dicot (Asteraceae, Urticaceae, Plantaginaceae, Euphorbiaceae, and Amaranthaceae) plant families . This section will focus on dicot weeds.…”

Do <b><i>Plantago lanceolata</i></b> Skin Prick Test-Positive Patients Display IgE to Genuine Plantain Pollen Allergens? Investigation of Pollen Allergic Patients from the North-East of France

“…Plantago lanceolata (English plantain) represents the most important allergen source among weeds from the Plantaginaceae family [1][2][3]. Plantain pollen is usually not included in routine allergy diagnosis, and its clinical relevance may thus be underestimated in some regions [1,4].…”

“…Plantain pollen is usually not included in routine allergy diagnosis, and its clinical relevance may thus be underestimated in some regions [1,4]. English plantain typically flowers between April and September and shows an overlapping pollination season with grasses [2,5,6]. It grows mainly in temperate climate zones and is native in the north-east of France [5,[7][8][9][10].…”

Distinct epitope structures of defensin‐like proteins linked to proline‐rich regions give rise to differences in their allergenic activity

“…[4][5][6] Extract-based allergy diagnosis of weed pollen is frequently challenging due to (i) polysensitization of patients, (ii) overlapping flowering periods, and (iii) similar allergen profiles. 7,8 Although molecule-based approaches can be exploited for diagnosis, solely Amb a 1, Art v 1, and Art v 3 are currently available for routine allergy diagnosis of Asteraceae pollen allergy. 2 Several studies showed that sensitization profiles to distinct allergens from the same weed are highly diverse in different geographic regions.…”

“…2 Several studies showed that sensitization profiles to distinct allergens from the same weed are highly diverse in different geographic regions. 4,7,9,10 Even molecules from the same protein family like lipid transfer proteins (LTP) or pectate lyases can show different sensitization potencies, and in this context, allergenic defensin-like proteins linked to a polyproline-rich region are interesting molecules. Those defensinpolyproline-linked proteins are exclusively found in pollen of the Asteraceae family, while defensin-like proteins alone are prevalent in higher plants and were recently also described as allergens in legumes.…”