Overview of allergenic molecules
Currently, more than one thousand allergens from various allergenic sources have been described. Most of these molecules, that are relevant for AIT decisions, belong to a limited number of protein families and have been extensively revised4,20,21. More than 40 % of the relevant plant allergens belong to six protein families: 2S albumins ,non-specific lipid transfer proteins (nsLTP)), legumins, vicilins , profilins and pathogenesis-related (PR)-10 proteins22. In contrast, there are other families with only a few but very relevant members, as they include major pollen allergens such as expansins, polcalcins, pectate lyases and defensin-like proteins. Concerning animal allergen families, four of them (cysteine proteases, lipocalins, tropomyosins and parvalbumins), account for over 70% of the relevant allergens (Table 1) 23. A separate category is formed by the allergens from hymenoptera venom (Table 2).